US2188361A - Apparatus for converting currents - Google Patents

Apparatus for converting currents Download PDF

Info

Publication number
US2188361A
US2188361A US16742237A US2188361A US 2188361 A US2188361 A US 2188361A US 16742237 A US16742237 A US 16742237A US 2188361 A US2188361 A US 2188361A
Authority
US
United States
Prior art keywords
current
switching
contacts
reactor
auxiliary
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
Inventor
Koppelmann Floris
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Siemens Schuckertwerke AG
Siemens AG
Original Assignee
Siemens AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Siemens AG filed Critical Siemens AG
Application granted granted Critical
Publication of US2188361A publication Critical patent/US2188361A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/20—Contact mechanisms of dynamic converters
    • H02M1/26—Contact mechanisms of dynamic converters incorporating cam-operated contacts

Definitions

  • the present invention relates to an apparatus for converting single phase or polyphase alternating current into direct current or vice versa, or single phase or polyphase alternating current into alternating current of another frequency by means 01' periodically operated mechanical contacts.
  • Such an apparatus is described in the copending application Serial No. 114,965, filed on December 9, 1936.
  • An apparatus of the abovementioned character differs from the known apparatus of similar type by the use of means for simultaneously influencing the current and the voltage across the switching gap of each phase. These means consist of a current distorting impedance connected in series with the switching gap, and of a current path connected in parallel relation to the make and break contacts.
  • the purpose of the simultaneous influencing of the current and voltage is to suppress the arcing when opening the make and breakcontacts by automatically causing the current to assume substantially the zero value shortly before the beginning of the opening of the contacts and to maintain the zero value for -a certain interval while the contacts are opened, whereas the current interrupted at the make and break contacts is at least partly maintained through the parallel path in such a manner that the voltage drop of the circuit to be interrupted is applied at first substantially to the impedances connected in series to the make and break contacts and that a great average operating current and a high average operating voltage, are not any more stressed at the moment at which the contacts are broken than in the caseof a weak current system in which currents of the order of magnitude of 1 ampere or less flow or in which an operating voltage of the order of 10 volts or less is present.
  • a particularly advantageous means for attaining the above-mentioned automatic distortion of the current is a so-called switching reactor which is series-connected to the make and break contacts.
  • a switching reactor is also described in the above-mentioned copending application Serial No. 114,965. It consists oi an inductance coil whose iron core consists of a particularly high-graded ferromagnetic iron alloy of extreme permeability and of extremely great saturation induction, which iron is suddenly saturated with increasing current upon exceeding a predetermined current value, as is manifested by a relatively sharp saturation bend of its magnetization curve.
  • the number of turns of the coil is so chosen that the coil is unsaturated only at very small instantaneous values of the current in the neighborhood of the zero value and is saturated already upon exceeding an instantaneous value of the current of the order of one thousandth or of one ten-thousandth of the normal average operating current.
  • the resistance of such a reactor is very small in the saturated state. It permits, therefore, in the state of saturation the passage of the normal operating current during the greatest portion of each period during which the current flows without appreciably impeding thiscurrent.
  • the contacts may be broken without there occurring any arcing, if as a result of a suitable dimensioning of the current path parallel to the contacts care is taken to increase the restriking voltage only slowly.
  • the resistance of the parallel path must be so rated that it amounts only to a fraction of the resistance or the reactor in the unsaturated state;
  • the total voltage of the circuit distributes itself in proportion to the said resistances over the switching gap and the reactor, provided that all other resistances may be neglected.
  • the total voltage of the circuit is therefore almost exclusively applied to the reactor in the unsaturated state.
  • the latter may be biased additionally opposite to .the direction of the operating current to be transmitted in such a manner that the desaturation of the reactor occurs already while the operating current varies according to the descending portion of its current curve and still has a positive instantaneous value, i. e., before the operating current passes through its zero value.
  • the additional magneticbias may be efiected with the aid of direct current or by an alternating current which has the same frequency as the alternating current to be converted and whose position of .phase is adjustable with the aid of an induction regulator or the like in such a manner that the magnetic bias has at the desired moment before the breaking of the contacts the desired direction opposite to the direction of the operating current.
  • the present invention relates to improvements of converting apparatus of the above-outlined type, and especially refers to the switching-in operation of the contacts. The nature of these improvements will be apparent from the following considerations.
  • the above-mentioned means for simultaneously influencing the current and the voltage may under certain circumstances cause relatively large currents to occur when switching in the make and break contacts. These large currents may be due to the fact that the switching reactor--which when being switched out is unsaturated and has a very high resistance-may under certain conditions be just in the state of saturation when being switched in and therefore have a very small resistance. A further reason for the occurrence of large currents at the switching in moment is that the condensers connected in parallel relation to the make and break contacts are discharged when switching in.
  • the main object of the present invention consists in preventing the creation of large currents or current surges at the closing moment of the contacts when switching in the circuit breakers.
  • a further object of the invention consists in reducing the voltage existing across the switching gap immediately before the closing moment of the contacts in such a manner that a sparking cannot take place before the closure of the contacts.
  • an additional reactor is employed in connection with every circuit breaker to which a switching reactor is connected in series.
  • This additional reactor hereinafter referred to as switching-in reactor is so arranged that it lies shortly before and when switching in the circuit breaker in a circuit which includes in series the make and break contacts, the condenser of the parallel path and the switching-in reactor.
  • the switching-in reactor has also an auxiliary exciting winding by means of which it is so biased with direct current or alternating current that it is magnetically saturated when switching out i. e., the switching-in reactor has a low resistance for the current flowing therethrough when switching out, whereas it is unsaturated when switching in so that it has a high resistance for the current flowingtherethrough at the switching-in moment.
  • FIG. 1 shows a three-phase converting apparatus, the fundamental total connection according to the above-mentioned copending application Serial No. 114,965 being shown schematically while the switching apparatus is illustrated more in detail.
  • Figs. 2 to 4 show three different forms of the invention in which for the sake of simplicity only that portion of one phase is indicated which manifests the inventive improvements, whereas the mechanical portion of the converting apparatus is shown schematically.
  • the part circuits shown may be employed in a single phase system or may be according to Fig. 1 combined to arrangements of any number of phases.
  • Fig. 4a shows a modified detail of Fig. 4.
  • Fig. 5 shows in detail the contact device of the arrangement according to Fig. 4 on an enlarged scale.
  • the arrangement according to Fig. 1 consists of four main groups of parts, namely the power source I which supplies the converting apparatus with three-phase alternating current through an intermediate transformer; the switching device 2 which is equipped with an adjustable synchronous drive; the device 3 for influencing the voltage and the devices 4 for influencing the current.
  • the secondary winding is star-connected.
  • the neutral point is connected to the current consuming device 2" through a conductor.
  • From the free terminals of the windings I2I, I22, I23 extend the main conductors to the switching reactors 304, 3, 324 which are wound on the magnet cores 305, 3I5, 325.
  • the cores are provided with auxiliary exciting windings 3I'I, 3I8, 3I9 which are biased by a direct-current source (battery) I9I.
  • a rheostat 360 which permits adjusting the magnitude of the biasing current to the desired value depending upon the operatirg conditions. Furthermore, in the direct-current circuit is inserted a reactance coil 36l which prevents the pulsations of current which might be caused by the inductive coupling of the biasing coil with the main coils of the Tl of the secondary windings I2I, I22, I23.
  • each of the make and break contacts I4I. I42, I43 which are arranged in pairs. The latter are placed on the intermediate plate I20 of an insulating frame I90. Each stationary contact pair cooperates with a movable contact I5I, I52, I53 which in the closed position bridges the make and break contacts and is under the influence of a spring I1I, I12, I13 respectively which in turn presses against a cross bar I30 of insulating material.
  • the main current circuit extends from the second contact of each contact pair to a common conductor I45 which forms the other pole of the current consuming device 2I0 and in which is inserted a smoothening inductance coil II4.
  • the movable bridge contacts I5I, I52, I53 perform in operation an upward movement which is brought about by tappets IGI, I62, I63 consisting of insulating material.
  • the latter are under the influence of a spring I1I, I12, I13 respectively and are operated by cams I8I, I82, I03 which are firmly mounted on a shaft I08 and angularly displaced by 120 with respect to one another.
  • the shaft I08 is mounted in the frame I90 and is driven by the synchronous motor I06 through an intermediate coupling I01.
  • the synchronous motor is connected to the secondary winding 226 of an induction regulator whose primary side is connected to the output terminals
  • the induction regulator 'serves to vary the phase position of the rotating field of the driving motor I06; in this manner the moments at which the contacts are closed and opened are so adjusted that the opening of the contacts always occurs during the above explained weak current intervals in the neighborhood of the zero value of the current to be interrupted.
  • auxiliary circuit breakers 90 operating with current collectors (brushes) 95 which are held by supports 99 secured to the intermediate plate I20. The purpose and the op eration of the last-mentioned auxiliary circuit breakers are hereinafter described in connection with Fig. 4.
  • I26 a control of the current and the voltage may also be attained within wide limits (of. the above-mentioned copending application Serial No. 122,232),
  • 304 denotes the switching reactor with the magnet core 305 and the auxiliary biasing winding 3I1 which is connected to the directcurrent source I3I through the rheostat 360 and the reactor 35L
  • the main conductor extends from the switching reactor 304 through circuit breaker 2 to the conductor I45 leading to the current consuming device 2I0 (not shown in Fig. 2).
  • an impedance arrangement II5. This arrangement consists of a condenser l and a low-ohmic resistor I5.
  • the parallel path is further inserted an auxiliary switching reactor 504 which need only be rated for a small current, since the currents flowing through the parallel path amount to a fraction of the main current or only flow for a very short time.
  • the magnet core 505 of the reactor 504 is also provided with a biasing winding denoted by the numeral 5H and connected to a battery '92 through a rheostat 560 and a reactor 56I.
  • the direction of current of the magnetic bias is so adjusted as to exert a magnetic action in the same direction as the current flowing into the condenser I5 when opening the contacts.
  • the magnitude of the exciting current is so adjusted that the core 505 of the switching-in coil is just saturated if no current flows in the main winding 504.
  • auxiliary switching-in reactor 504a with the core 505a and the biasing winding 5I1a is provided in Fig. 2.
  • the biasing windings BH and 5I1a are connected in series.
  • This arrangement may be advantageously employed not only in the manner as shown in the embodiment of Fig. 2 but also represents a valuable improvement in all switching devices of any arrangement, such as is, for instance, the case with rectifiers and inverters of difierent types, highly sensitive regulators and relays to which a condenser is connected in parallel relation for facilitating the switching out operations.
  • an auxiliary switching reactor 504 is not arranged in the parallel path but directly in series with the circuit breaker 2.
  • the iron core 605 of this auxiliary switching reactor is provided with two auxiliary exciting windings H1 and M10.
  • the exciting winding BI1 is fed by the battery I03 through a rheostat 650 and a reactor 65L
  • the exciting winding 6I1a is connected to an altermating-current source I95. The latter must have the same frequency as the alternating current taken from the main transformer.
  • the exciting winding 6I1a may, for instance, be directly connectedif desired, through an auxiliary induction regulator 664 serving to accurately adjust the proper position of phase-to one of the secondary windings of the feeding main transformer itself which has the suitable position of phase for this purpose.
  • auxiliary exciting circuit lies a rheostat 853 and another auxiliary switching reactor 104 with an iron'core 105.
  • This auxiliary switching reactor 104 need only be rated for a very small current.
  • Its iron core 105 has an additional exciting winding H1 which is fed from a battery I84 through a resistor I60 and a reactance coil IN.
  • the current flowing in the exciting winding BI! is so adjusted that the core 605 is biased in the opposite direction as by the main current.
  • the magnitude of this exciting current is so adjusted with the aid of the rheostat 660 that the state of saturation is nearly attained by the biaseifected by winding 6H alone. If the main current begins to flow shortly after the contacts have been closed the switching reactor 604 has a very high resistance and consequently maintains the current at a low value until the state of saturation is attained when the current flows in the opposite direction.
  • the exciting winding 6lla is not eiIective during this interval, for the magnitude and direction of the biasing current in the winding 1 l1 and the magnitude and phase position of the alternating current taken from the power source I85 are so chosen that the core 105 is unsaturated shortly before the closure of the contacts 2 so that the auxiliary switching reactor I04 has a very high resistance and the current flowing therein and therefore in the winding lil'la is practically zero. However, as soon as the contacts are closed the core 105 attains the state of saturation. In this manner the resistance of the switching coil 104 drops to a very low value. The switching reactor 104 permits therefore substantially without any hindrance the passage of the alternating current taken from the power source I95.
  • the magnitude and the position of phase of this alternating current is so chosen that it exerts a magnetic effect. on the core 605 in the same direction as the main current in the switching reactor 604.
  • the switching reactor 604 is therefore rendered ineffective by the alternating current during the period of the flow of current proper and during the time the main'contacts 2 are being separated.
  • a special parallel path is provided as shown in the embodiment according to Fig. 3 in which is inserted a low-ohmic resistor 624 and which is controlled byan auxiliary contact device 620.
  • This auxiliary contact device consists of two stationary contacts 6 and a revolving part 65I which is driven in synchronism with the driving shaft for the main contact device and is so adjusted that it closesa parallel circuit shortly before the main contacts close.
  • the auxiliary contact device 620 Since the auxiliary contact device 620 has only to carry a very small current momentarily and since a good contact is not essential insofar as also in the case of a relatively bad contact the resistance of the parallel path is always so small as to be neglected with respect to the resistance of the auxiliary switching reactor 4 which is at the same time in an unsaturated state, a slight consumption of the auxiliary contact device 620 may be put up without impairing the normal operation of the converter.
  • the auxiliary contact may be made of a,material which is particularly resistant to arcing; for instance of tungsten. For the above-mentioned reasons it the main contacts.
  • the total voltage distributes itself over the contact device 2 'and the auxiliary switching reactor 604 according to the ratio of the resistance of the parallel path in which the resistor 624 and the auxiliary switching device 620 are inserted, to the resistance of the auxiliary switching reactor 604 which is in an unsaturated state. Since the resistance of the parallel path amounts only to a fraction of the resistance of the unsaturated auxiliary reactor the voltage across the main contacts shortly before their closure is so small as to be neglected. An arcing will therefore not occur at the main contacts.
  • auxiliary switching reactor 604 is connected in series with the interrupting device 2 and both are bridged by the parallel path through the resistance combination I I5 consisting of an ohmic resistor l5 and a condenser IS.
  • the iron core 605 of the auxiliary switching reactor 604 carries an auxiliary winding 6" for effecting a magnetic bias. Winding 6
  • the magnetic bias is soadjusted that shortly before the engagement of the contacts l4l, Mia and IN the core 605 of the auxiliary switching reactor is in a nearly saturated state opposite to the direction of the main current which begins to flow through the auxiliary switching reactor 604 after the closure of the contacts.
  • This main current therefore maintains practically the zero value until it has reversed the magnetization of the iron core and until the state of saturation is attained in the other direction. Only in this case themain current may flow through reactor 604 without hindrance.
  • a further parallel path is directly parallel connected to the contacts I and I a, the resistance of this parallel path being small compared to the resistance of the auxiliary switching coil 604 which is at this moment in an unsaturated .state.
  • the parallel path consists of a discharge tube 820 whose grid "I is connected through a high-ohmic resistor 82! to an auxiliary contact 24!, the closure of which leads.
  • the .grid MI is biased by a battery I81 through a high-ohmic resistance 823.
  • the cathode is heated by a heating battery I98.
  • a protective resistor 824 is connected in series with the discharge tube 820.
  • a condenser MS with a parallel-connected resistor 824 may be series-connected to the discharge tube.
  • Another switching reactor 804 may be arranged in the lead to the discharge tube in order to protect the tube against a danger ous over-current.
  • the iron core 805 of the reactor 804 is provided with an additional biasing winding 8
  • auxiliary switching reactor 804, 805 is highly saturated and permits the current to flow in normal operation through the discharge tube 820 without exceeding the saturation point In cases where considerably greater currents may occur which would stress and destroy the discharge tube the auxiliary switching reactor 804, 805 comes within the working range below the saturation so that such dangerous currents are prevented by the high inductive resistance of the unsaturated auxiliary switching reactor 804.
  • a condenser 8I5 with a parallel-connected ohmic resistance 824 is arranged in series with the auxiliary switching reactor 804 the condenser protects also the discharge tube even if themagnetization of the auxiliary switching coil 804, 805 has attained the saturation point in the opposite direction after reversal by the interfering current.
  • the auxiliary reactor 804, 805, therefore, may be dimensioned smaller, as if the condenser 8I5 and the parallel resistor 824 were not available.
  • a resistor 808 having a high resistance may be parallel-connected to the auxiliary switching reactor 804 in order to facilitate the equalization of the magnetic energy when reversing the magnetism thereof.
  • the grid bias of the discharge tube 820 is adjusted to such a high value that the flow of current therethrough is prevented so long as the auxiliary contact 24I is not in engagement 7 with the movable contact I5I.
  • the latter is connected to the stationary contact I4Ia by a flexible auxiliary conductor.
  • the discharge tube 820 allows therefore a current to flow therethrough. Consequently, the voltage at the main contacts HI and I4Ia drops substantially to a value equal to the sum of the ignition voltage of the discharge tube 820 and of the voltage drop in the protective devices M5, 824, 804 and 808.
  • This residual voltage across the contacts amounts only to a fraction of the total voltage which is substantially applied to the auxiliary switching reactor 604 being just unsaturated at this moment. Owing to the small residual voltage across the switching gap an arcing cannot occur across the contacts MI and I5I.
  • FIG. 5 An advantageous arrangement of the leading auxiliary contact 24I is illustrated in Fig. 5 in which the contact device shown in Fig. 4 is illustrated on an enlarged scale.
  • the contact device consists as shown in Fig. 1 of the stationary contacts I4I, I4Ia secured to the insulating plate I20.
  • the movable contact I5I is under the influence of the spring I'II which presses against a second insulating plate I30.
  • the drive is brought about by'the tappet IBI.
  • the terminals for the leads are denoted by the numeral 245.
  • the stationary contact MM is provided with a bore 242 in which moves the pin contact 2.
  • the contact pin has a collar 246 and may be moved within a piston-shaped sleeve 243.
  • the movement within this sleeve is limited by a stop 259 and an inner nut 240 which is adjustable by means of a fine thread 241.
  • the collar 246 is pressed against the adjusting nut 248 by a spring 249.
  • the piston-shaped sleeve 243 is movably arranged within a second sleeve 244 which is secured to the insulating plate I by means of an angle iron.254.
  • the outer sleeve 244 is closed at both ends by covers 252 and 253 consisting of insulating material and being each provided with a bore.
  • the bore of the cover 253 serves as'a guide for the contact pin 24I.
  • a weak spring 25I which tends to press the sleeve 242 in the upward direction.
  • the movement is, however, damped by the air above the sleeve 243 and is limited by the engagement of the collar 245 of the contact pin 2 with the stop 259 upon the closure of the contacts.
  • the piston-shaped sleeve 243 may therefore move in the upward direction during the operating period only gradually by the same amount as the upper end of the auxiliary contact 24I wears off with time.
  • the contact pin 2 is automatically readjusted during the operating period by such an amount that its upper end projects beyond the contact surface of the stationary contact I4
  • the length of this portion of the pin may be so adjusted with the aid of the adjusting nut 248 that the time interval which elapses between the engagement of the auxiliary contact 2 and the movable contact I5I and that of the movable contact I5! and the stationary main contact 14!, has the desired value. This value is maintained constant during the operation owing to the automatic adjustment by the spring 25I.
  • a conductor 25'! extends through the bore of the lower cover 252 from the contact pin 24I to the terminal-258.
  • Another auxiliary conductor 251a extends from the movable contact I5I to the stationary contact I4Ia. Both auxiliary conductors carry only the current flowing in the grid circuit of the discharge tube 820 and are therefore very thin.
  • a device by which the auxiliary switching reactor 604 is' short-circuited during the period of flow of current proper consists of a contact device driven in synchronism with the shaft and of the brushes which are connected to the ends of the reactor 604 through conductors.
  • the contact device 90 consists of two segments 9
  • the short-circuit of the switching reactor is therefore not suddenly eliminated but a resistance is at first gradually inserted in the bridging short-circuit connection. In this manner the interruption of the short-circuit connection is rendered as sparkless as possible.
  • auxiliary switching reactor 604 instead of connecting the short-circuit conductor of the brushes 95 directly to the ends of the auxiliary switching reactor 604 the latter may be provided according to Fig. 4a with an additional short-circuit winding 606 having a slight leakage to which the bridging contact device 90, 95 is connected.
  • the revolving contact device 90 is mounted on the same shaft I08 as the driving cams for the contact device.
  • the supports 99 for the brushes 95 are secured to the plate I20 of the insulating frame I90.
  • An arrangement for converting alternating current into direct current or vice versa, or alternating current of one frequency into alternating current of another frequency comprising a switching device having mechanically operated make and break contacts, means for simultaneously influencing thecurrent and voltage across the switching gap, said means comprising a switching reactor series-connected with said make andbreak contacts and designed to abruptly increase its impedance at small instantaneous values of the current in the neighborhood of its zero value, and a voltage-biasing impedance path parallel-connected to said make and break contacts for reducing the operating voltage recurring between said contacts, in combination with a variable auxiliary inductance designed to have a high resistance when switching in said'make and break contacts, said inductance being seriesconnected in a circuit including said make and break contacts and said parallel path.
  • a current converting arrangement comprising a switching device having mechanically operated make and break contacts, means for simultaneously influencing the current and voltage across the switching gap, said means comprising an inductance coil series-connected with said contacts and having a magnetic core designed to become abruptly unsaturated at current intensities near the zero value and of a current path including capacitors arranged in parallel to said make and break contacts for reducing the operating voltage recurring between said contacts, in combination with an auxiliary switching-in reactor connected in series with the make and break contacts in the circuit including said contacts and said parallel path, said switching-in reactor having a magnet core designed to be unsaturated only at small instantaneous current values in the neighborhood of the zero value and to become saturated upon the instantaneous current exceeding a given value which amounts to a fraction of the mean current carried by said switching-in reactor in the state of saturation.
  • a current converting arrangement comprising a switching device having mechanically operated make and break contacts, means for simultaneously influencing the current and voltage across the switching gap, said means comprising a current-biasing reactor series-connected to said make and break contacts and a voltage-biasing current path parallel-connected to said make and break contacts for reducing the operating voltage recurring between said contacts, in combination with an auxiliary switching-in reactor connected in series with said make and break contacts in the circuit including said make and break contacts and said parallel path, said switching-in reactor having a magnet core designed to become abruptly unsaturated upon the lowering of the instantaneous current intensity to values in the neighborhood of the zero value, a biasing winding arranged on the core of said switching-in reactor, and a biasing circuit connected to said winding, said circuit including an auxiliary current source and variable means for controlling the magnetic bias effected by said winding.
  • a current converting arrangement comprising a switching device having mechanically operated make and break contacts,'means for simultaneously influencing the current and voltage across the switching gap, said means comprising a current-biasing reactor series-connected to said make and break contacts and designed to periodically increase its reactance at low current intensities, and a voltage-biasing current path parparallel path, said switching-in reactor having a magnet core designed to become abruptly unsaturated upon the lowering of the instantaneous current intensity to values in the neighborhood of the zero value, a biasing winding disposed on the core of said switching-in reactor, a biasing circuit connected to said winding, an alternating current source having the frequency of the current to be interrupted by said contacts, said source being connected in said biasing circuit, and means in said circuit for controlling the phase position of the biasing current with respect to the phase position of said current to be interrupted.
  • a current converting arrangement comprising a switching device having mechanically operated make and break contacts, means for simultaneously influencing the current and voltage across the switching gap, said means comprising 4 a current-biasing reactor series-connected to said make and break contacts and designed to periodically increase its reactance at low current intensities, and avoltage-biasing current path parallel-connected to said make and break contacts for reducing the operating voltage recurring between said contacts, in combination with an auxiliary switching-in reactor connected in series with said make and break contacts in the circuit including said make 'and break contacts and said parallel path, said switching-in reactor having a magnet core designed to become abruptly unsaturated upon the lowering of the instantaneous current intensity to values in the neighborhood of the zero value, a biasing winding arranged on the core of said switching-in reactor, and an energizing circuit connected to said winding, said circuit being so adjusted that said switching-in reactor is in the state of saturation upon the opening of said break and make contacts.
  • a switching reactor having an inductance winding seriesconnected with said device so as to be traversed by the alternating current to be'controlled by said device and a magnet core designed to be uncore
  • a second switching reactor having a main winding connected with said auxiliary biasing winding of said first reactor and a magnet core also designed to be unsaturated at said small instantaneous current intensities and saturated upon exceeding a predetermined intensity amounting to a fraction of the normal mean operating current flowing through said main winding of said second reactor, a biasing winding disposed on the core of said second reactor, and an energizing circuit connected with said latter biasing winding, said energizing circuit being adjusted to cause said second reactor to have in a iven interval within each cycle of said alternatn current an increased inductive resistance so that in said interval the auxiliary biasing current controlling said first reactor has a minimum value.
  • a current converting arrangement comprising a switching device having mechanically operated make and break contacts, means for simultaneously influencing the current and voltage across the switching gap, said means comprising a self-saturating switching reactor seriesconnected to said make and break contacts for decreasing the current intensities in the neighborhood of the passage of the current through its zero value and voltage-biasing means connected in parallel to said make and break contacts and being provided with a variable auxiliary impedance designed to have an increased impedance value when switching in said make and break contacts, and an auxiliary contact device for bridging said auxiliary impedance during a given interval within each current cycle, said interval including at least the'period of the opening oi said contacts.
  • a current converting arrangement comprising a switching device having mechanically operated make and break contacts, means for simultaneously influencing the current and voltage across the switching gap, said means comprising a self-saturating switching reactor series-connected to said make and break contacts for decreasing the current intensities in the neighborhood of the passage of the current through its zero value and voltage-biasing means connected in parallel to said make and break contacts and being provided with a variable auxiliary impedance designed to have an increased impedance value when switching in said make and break contacts, an auxiliary contact device for br dging said auxiliary impedance, and means for operating said auxiliary contact device.
  • a current converting arrangement comprising a switching device having mechanically operated make and break contacts, means for simultaneously influencing the current and voltage across the switching gap, said means comprising a self-saturating switching reactor series-connected to said make and break contacts for decreasing the current intensities in the neighborhood of the passage of the current through its zero value and voltage-biasing means connected in parallel to said make and break contacts and being provided with an auxiliary switching reactor designed to have an increased resistance when switching in said make and break contacts, said auxiliary reactor having a magnet core and an additional biasing winding arranged on said core so as to have a slight leakage, and an auxiliary contact device for bridging said additional winding during the opening of said make and break contacts.
  • a current converting arrangement comprising a switching device having mechanically operated make and break contacts, means for simultaneously influencing the current and voltage across the switching gap, said means comprising a self-saturating switching reactor series-connected to said make and break contacts for decreasing the' current intensities in the neighborhood of the passage of the current through its zero value and voltage-biasing means connected in parallel to said make and break contacts and being provided with a variable auxiliary impedance designed to have an increased impedance value when switching in said make and break contacts, a parallel path containing current-limiting impedances. said path being arranged in parallel to said make and break contacts in order to reduce the voltage prevailing across the switching gap between said contacts, and means for connecting said parallel path with said make and break contacts shortly before their closure.
  • a current converting arrangement comprising a switching device having mechanically operated make and break contacts, means for simultaneously influencing the current and voltage across the switching gap, said means comprising a self-saturating switching reactor series-connected to said make and break contacts for decreasing the current intensities in the neighborhood of the passage of the current through its zero value and voltage-biasing means connected in parallel to said make and break contacts and being provided with a variable auxiliary impedance designed to have an increased impedance value when switching in said make and break contacts, a parallel path containing current-limiting impedances, said path being arranged in parallel to said make and break contacts in order to reduce the voltage prevailing across the switching gap between said contacts, an auxiliary contact device for closing said parallel path shortly before the closure of said make and break contacts, and means for operating said auxiliary contact device in synchronism with said switching device.
  • a converting arrangement comprising a switching device having mechanically operated contacts.
  • means for simultaneously influencing the current and voltage across the switching gap consisting of a current-biasing selfsaturating switching reactor series-connected to said contacts and of a voltage-biasing path parallel-connected to said contacts, said means being further provided with a variable auxiliary impedance having a high impedance value when closing said contacts, a second parallel path including current-limiting devices and being directly parallel-connected to the make and break contacts in order to reduce the voltage prevailing across the switching gap between said contacts, said second parallel path containing a grid controlled discharge tube, an auxiliary current source connected in the grid circuit of said tube for supplying a blocking voltage to said grid, an auxiliary contact device connected with said grid circuit so as to diminish when operated said grid voltage in order to allow a current flow through said tube, and means for operating said auxiliary contact device in synchronism with said switching device so as to be actuated shortly before the closure of the contacts of said switching device.
  • a converting arrangement comprising a switching device having mechanically operated make and break contacts, means for simultaneously influencing the current and voltage across the switching gap, said means consisting of a self-saturating switching reactor series-connected to the make and break contacts and of a voltage-biasing path parallel-connected to said make and break contacts, and being provided with a variable auxiliary impedance having a high impedance value when closing the make and break contacts, an automatic device for bridging said make and break contacts shortly before their closure through a second parallel path including current-limiting impedances and being directly parallel-connected to said make and break contacts in order to reduce the voltage prevailing across the switching gap.
  • said bridging device comprising a grid controlled discharge tube, an ohmic resistance series-connected with said tube for protecting said tube against overload in case of disturbances, and means for controlling the grid voltage of said tube in dependency upon the operation of said make and break contacts.
  • a converting arrangement comprising a switching device having mechanically operated make and break contacts, means for simultaneously influencing the current and voltage across the switching gap, said means consisting of a self-saturating switching reactor series-connected to said make and break contacts and of a cur- (iii rent path parallel-connected to the make and break contacts, and being provided with a variable auxiliary impedance having a high impedance value when closing said make and break contacts, a device for bridging said make and break contacts shortly before their closure through a second parallel path including ourrent-limiting devices and being directly parallelconnected to said make and break contacts in order to reduce the voltage prevailing across the switching gap, said bridging device comprising a grid controlled discharge tube, a parallel-connection disposed in series with said tube and including a condenser and an ohmic resistor for protecting said tube against overload in case of disturbances, and means for controlling said tube in dependency upon the operation of said make and break contacts.
  • a converting arrangement comprising a switching device having mechanically operated make and break contacts, means for simultaneously influencing the current and voltage across the switching gap, said means consisting of a self-saturating switching reactor series-connected to said make and break contacts and of a current path parallel-connected to said make and break contacts, and being provided with an auxiliary switchingein reactor having a high resistance when closing said make and break contacts, a device for bridging said make and break contacts shortly before their closure through a second parallel path including current-limiting devices and being directly parallel-connected to said make and break contacts in order to reduce the voltage prevailing across the switching gap, a grid controlled discharge tube arranged in said second parallel path, an auxiliary switching reactor having a main winding series-connected with said tube and a magnet core designed to become unsaturated at low current intensities near the zero value, a biasing winding on said core, and an energizing circuit connected with said biasing winding, said energizing current being adapted to supply said biasing winding with a current acting in opposition to the current flowing through
  • a converting arrangement comprising a switching device having mechanically operated main contacts, means for simultaneously influencing the current and voltage across the switch ing gap, said means consisting of a self-saturating switching reactor series-connected to said contacts and of a current path parallel-connected to said contacts, and being provided with a variable auxiliary impedance having a high impedance value when closing said contacts, an impedance arrangement disposed in parallel to said contacts and designed to bridge the switching gap shortly before each closure of said contacts, an auxiliary contact device for controlling said bridging arrangement, said contact device consisting of a contact pin movably disposed in a bore of a stationary contact of said main contacts so as to protrude from the contact surface of said stationary main contact in order to cooperate with the movable countercontact of said stationary main contact, spring means for holding said pin in said protruding position, and an adjustable stop for securing said position.
  • A' converting arrangement comprising a switching device having mechanically operated main contacts, means for simultaneously influencing the current and voltage across the switching gap, said means consisting of a self-saturating switching reactor'series-connected to said contacts and of a current path parallel-connected to 5 said contacts, and being provided with a variable auxiliary impedance having a high impedance value when closing said contacts, an impedance arrangement disposed in parallel to said contacts and designed to bridge the switching gap shortly before each closure of said contacts, an auxiliary contact device for controlling said bridging arrangement, said auxiliary contact device having a pin movably arranged in a bore of a stationary main contact so as to protrude from said contact in order to cooperate with the movable countercontact of said stationary main contact, a pistonshaped sleeve movably disposed on said pin and connected with said pin by a spring and an adjustable stop arrangement for limiting the rein-- tive movements between said sleeve and said pin, a stationary air cylinder surrounding said sleeve and designed for dampening
  • voltage-biasing means connected in parallel to said device for reducing the increase of the operating voltage recurring at the opening moment across said device, an inductance coil connected in a circuit including in series said device and said means, said coil being provided with a core of ferromagnetic material having a high permeability and a magnetization curve with a sharp saturation bend, a biasing winding disposed on said core, and an energizing circuit connected with said winding and adapted to cause a desaturating bias of said core shortly before the closing moment of said device, thereby abruptly increasing the inductance of said coil.
  • a contact device for opening and closing an alternating current circuit in a given time relation to the cycle of said current, said device being adjusted to effect said opening at a moment in the neighborhood of the zero value of said current, in combination, means connected with said circuit for distorting the curve of said current so as to producea weak current interval including said opening'rnoment, voltage-biasing means connected in parallel to said device for reducing the increase of the operating voltage recurring at the opening moment across said device, an inductance coil connected in a circuit including in series said device and said means, said coil being provided with a core of ferromagnetic material having a high permeability and a so magnetization curve with a sharp saturation bend, a biasing winding disposed on said core, and an energizing circuit connected with said winding and adapted to cause a desaturating bias of said core shortly before the closing moment of 05 said device, thereby abruptly increasing the inductance of said coil.
  • a contactdevice for periodically opening and closing an alternating current circuit in synchronism with the cycle of said current said 7 device being adjusted to efl'ect said opening at a moment in the neighborhood of the zero value of said current, in combination, a periodically variable impedance connected in said circuit and designed to increase its impedance value during an interval including said opening moment, a reactive impedance path connected in parallel to the gap of said contact device for decreasing the voltage across said gap during the opening operation, an inductance coil series-connected in the circuit including said gap and said parallel path, said coil being provided with a core of ferromagnetic material having a high permeability and a magnetization curve with a sharp satin ation bend, a biasing winding disposed on said core, and a biasing circuit connected with said winding and adapted to control the state of magnetization of said core and thereby the inductance of said coil shortly before the contact closing moment of said device in order to counteract the sparking tendency caused by said parallel path during the closing operation of said device.
  • a device for opening and closing an alternating current circuit in a given time relation to the cycle of said current said device being adjusted to eifect said opening at a moment in the neighborhood of the zero value of said current, in combination, means connected with said circuit for distorting the curve of said current so as to produce a weak current interval including said opening moment, a capacitive path connected in parallel to said device for decreasing the voltage across said device during the opening operation, an inductance coil series-connected in the circuit including in series said device and said parallel path, said coil being provided with a core of ferromagnetic material having a high permeability and a magnetization curve with a sharp saturation bend, a biasing winding disposed on said core, and a biasing circuit connected with said winding and adapted to control the state of magnetization 01' said core and thereby the inductance of said coil shortly before the closing moment of said device in order to impede the capacitive discharge current of said path during the closing operation of said device.
  • said coil being provided with a core of ferromagnetic material having a high permea bility and a magnetization curve with a sharp saturation bend, a biasing winding disposed on said core, and a biasing circuit connected with said winding, and adapted to control the state of magnetization of said core and thereby the inductance of said coil shortly before the closing moment of said device in order to impede the capacitive discharge current of said path during the closing operation of said device.
  • a contact device for opening and closing an alternating current circuit in a given time relation to the cycle of said current, said device being adjusted to eiiect said opening at a mo ment in the neighborhood of the zero value of said current, in combination, means connected with said circuit for distorting the curve of said current so as to produce a weak current interval including said opening moment, a reactive path connected in parallel to the gap of said contact device for decreasing the voltage across said gap during the opening operation of said device, a variable impedance series-connected in the circuit including said gap and said parallel path, controlling means for causing said variable impedance to vary its impedance value shortly before the contact closure of said device so as to counteract the sparking tendency caused by said parallel path at the closing moment of said device.
  • a current converting arrangement comprising a switching device having periodically operating make and break contacts, a saturable reactor series connected to said contacts for periodically producing a weak current interval at low current intensities, means for controlling said reactor to effect said weak current interval in a desired time relation to the operation of said switching device, a second saturable reactor having one pole connected with one of said contacts and the other pole connected with the other contact of said switching device so as to form part of a parallel circuit with respect to the switching gap between said contacts, and means for controlling said second reactor to cause said reactor to increase its reactance shortly before the closing moment of said contacts.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Driving Mechanisms And Operating Circuits Of Arc-Extinguishing High-Tension Switches (AREA)

Description

Jan. 30, 1940. F. KOPPELMANN 2,188,361
APPARATUS FOR CONVERTING CURRENTS Original Filed Oct. 5, 1937 2 Sheets-Sheet l Jan. 30, 1940. F. KOPPELMANN APPARATUS FOR CONVERTING CURRENTS Original Filed. Oct. 5, 1937 2 Sheets-Sheet 2 Patented Jan. 30, 1940 UNITED STATES PATENT OFFICE Floris Koppelmann, Berlin-Siemensstadt, Germany, aaaignor to Siemena-Schuckertwerke Aktiengeselischait,
Berlin-Siemensstadt,
Ger-
y, a corporation oi Germany Application October 5, 1937, Serial No. 167,422. Renewed May 2, 1939. In Germany October 5, 1936 i 24 Claims.
The present invention relates to an apparatus for converting single phase or polyphase alternating current into direct current or vice versa, or single phase or polyphase alternating current into alternating current of another frequency by means 01' periodically operated mechanical contacts. Such an apparatus is described in the copending application Serial No. 114,965, filed on December 9, 1936. An apparatus of the abovementioned character differs from the known apparatus of similar type by the use of means for simultaneously influencing the current and the voltage across the switching gap of each phase. These means consist of a current distorting impedance connected in series with the switching gap, and of a current path connected in parallel relation to the make and break contacts. Some particularly advantageous types of said means will be hereinafter described, and others which may also be used in connection with the present invention form the subject matter of the following copending applications: Serial No. 122,232, filed on January 25, 1937; Serial No. 129,987, filed on March 10, 1937; Serial No. 128,185, filed on February 27, 1937; Serial No. 125,363, filed on February 12, 1937; Serial No. 133,758, filed on March 30, 1937.
The purpose of the simultaneous influencing of the current and voltage is to suppress the arcing when opening the make and breakcontacts by automatically causing the current to assume substantially the zero value shortly before the beginning of the opening of the contacts and to maintain the zero value for -a certain interval while the contacts are opened, whereas the current interrupted at the make and break contacts is at least partly maintained through the parallel path in such a manner that the voltage drop of the circuit to be interrupted is applied at first substantially to the impedances connected in series to the make and break contacts and that a great average operating current and a high average operating voltage, are not any more stressed at the moment at which the contacts are broken than in the caseof a weak current system in which currents of the order of magnitude of 1 ampere or less flow or in which an operating voltage of the order of 10 volts or less is present.
A particularly advantageous means for attaining the above-mentioned automatic distortion of the current is a so-called switching reactor which is series-connected to the make and break contacts. Such a switching reactor is also described in the above-mentioned copending application Serial No. 114,965. It consists oi an inductance coil whose iron core consists of a particularly high-graded ferromagnetic iron alloy of extreme permeability and of extremely great saturation induction, which iron is suddenly saturated with increasing current upon exceeding a predetermined current value, as is manifested by a relatively sharp saturation bend of its magnetization curve. The number of turns of the coil is so chosen that the coil is unsaturated only at very small instantaneous values of the current in the neighborhood of the zero value and is saturated already upon exceeding an instantaneous value of the current of the order of one thousandth or of one ten-thousandth of the normal average operating current. The resistance of such a reactor is very small in the saturated state. It permits, therefore, in the state of saturation the passage of the normal operating current during the greatest portion of each period during which the current flows without appreciably impeding thiscurrent. However, as soon as the reactor, owing to the decrease of the current below a predetermined value, is' suddenly desaturated while the current according to the descending portion of its curve approaches the zero value, the resistance of the reactor assumes almost instantaneously a very high value which is several thousand times greater than the resistance in the saturated state. Consequently, the current flowing through the reactor during the period .of the desaturation is greatly impeded and there occurs a weak current interval during which the current intensity has ,a negligible value, i. e., is practically zero. The reactor must be so dimensioned that this interval is of the order of a millisecond. During this time the contacts may be broken without there occurring any arcing, if as a result of a suitable dimensioning of the current path parallel to the contacts care is taken to increase the restriking voltage only slowly. The resistance of the parallel path must be so rated that it amounts only to a fraction of the resistance or the reactor in the unsaturated state;
' the contacts.
then the total voltage of the circuit distributes itself in proportion to the said resistances over the switching gap and the reactor, provided that all other resistances may be neglected. The total voltage of the circuit is therefore almost exclusively applied to the reactor in the unsaturated state.
By an auxiliary winding on the magnet core of the reactor, the latter may be biased additionally opposite to .the direction of the operating current to be transmitted in such a manner that the desaturation of the reactor occurs already while the operating current varies according to the descending portion of its current curve and still has a positive instantaneous value, i. e., before the operating current passes through its zero value. The additional magneticbias may be efiected with the aid of direct current or by an alternating current which has the same frequency as the alternating current to be converted and whose position of .phase is adjustable with the aid of an induction regulator or the like in such a manner that the magnetic bias has at the desired moment before the breaking of the contacts the desired direction opposite to the direction of the operating current.
The present invention relates to improvements of converting apparatus of the above-outlined type, and especially refers to the switching-in operation of the contacts. The nature of these improvements will be apparent from the following considerations.
The above-mentioned means for simultaneously influencing the current and the voltage may under certain circumstances cause relatively large currents to occur when switching in the make and break contacts. These large currents may be due to the fact that the switching reactor--which when being switched out is unsaturated and has a very high resistance-may under certain conditions be just in the state of saturation when being switched in and therefore have a very small resistance. A further reason for the occurrence of large currents at the switching in moment is that the condensers connected in parallel relation to the make and break contacts are discharged when switching in. Furthermore, relatively high voltages may occur across the switching gap shortly before the engagement of Consequently, an arc may be produced when switching in, which carries immediately a current of relatively high intensity, whereby the contacts may be damaged and become useless after a relatively short operating period. Such damages are the more likely, if the contacts are made of good conducting metals, such as silver, copper or the alloys thereof for the purpose of reducing the voltage losses during the period of the current fiow. In series with the parallel-connected condensers, high-ohmic resistors could be connected by which the discharge current of the condensers is maintained small. The resistance of such resistors would, however, be so great in this case that the restriking voltage when switching out may not be sufficiently reduced and consequently the danger of an arcing now would be increased when switching out.
The main object of the present invention consists in preventing the creation of large currents or current surges at the closing moment of the contacts when switching in the circuit breakers.
A further object of the invention consists in reducing the voltage existing across the switching gap immediately before the closing moment of the contacts in such a manner that a sparking cannot take place before the closure of the contacts.
According to the invention an additional reactor is employed in connection with every circuit breaker to which a switching reactor is connected in series. This additional reactorhereinafter referred to as switching-in reactor is so arranged that it lies shortly before and when switching in the circuit breaker in a circuit which includes in series the make and break contacts, the condenser of the parallel path and the switching-in reactor. The switching-in reactor has also an auxiliary exciting winding by means of which it is so biased with direct current or alternating current that it is magnetically saturated when switching out i. e., the switching-in reactor has a low resistance for the current flowing therethrough when switching out, whereas it is unsaturated when switching in so that it has a high resistance for the current flowingtherethrough at the switching-in moment.
For a better understanding of the present invention reference may be made to the accompanying drawings in which Fig. 1 shows a three-phase converting apparatus, the fundamental total connection according to the above-mentioned copending application Serial No. 114,965 being shown schematically while the switching apparatus is illustrated more in detail.
Figs. 2 to 4 show three different forms of the invention in which for the sake of simplicity only that portion of one phase is indicated which manifests the inventive improvements, whereas the mechanical portion of the converting apparatus is shown schematically. The part circuits shown may be employed in a single phase system or may be according to Fig. 1 combined to arrangements of any number of phases.
Fig. 4a shows a modified detail of Fig. 4.
Fig. 5 shows in detail the contact device of the arrangement according to Fig. 4 on an enlarged scale.
The arrangement according to Fig. 1 consists of four main groups of parts, namely the power source I which supplies the converting apparatus with three-phase alternating current through an intermediate transformer; the switching device 2 which is equipped with an adjustable synchronous drive; the device 3 for influencing the voltage and the devices 4 for influencing the current.
To the supply circuit fed by the power source I are connected the input terminals IIII, I02, I03 of the primary windings III, H2, N3 of a transformer whose secondary windings are designated by the numerals I2l, I22, I23. The secondary winding is star-connected. The neutral point is connected to the current consuming device 2") through a conductor. From the free terminals of the windings I2I, I22, I23 extend the main conductors to the switching reactors 304, 3, 324 which are wound on the magnet cores 305, 3I5, 325. The cores are provided with auxiliary exciting windings 3I'I, 3I8, 3I9 which are biased by a direct-current source (battery) I9I. In the biasing circuit is inserted a rheostat 360 which permits adjusting the magnitude of the biasing current to the desired value depending upon the operatirg conditions. Furthermore, in the direct-current circuit is inserted a reactance coil 36l which prevents the pulsations of current which might be caused by the inductive coupling of the biasing coil with the main coils of the Tl of the secondary windings I2I, I22, I23.
switching coils from reaching the direct-current source.
From the switching coils extend main conductors to each of the make and break contacts I4I. I42, I43 which are arranged in pairs. The latter are placed on the intermediate plate I20 of an insulating frame I90. Each stationary contact pair cooperates with a movable contact I5I, I52, I53 which in the closed position bridges the make and break contacts and is under the influence of a spring I1I, I12, I13 respectively which in turn presses against a cross bar I30 of insulating material. The main current circuit extends from the second contact of each contact pair to a common conductor I45 which forms the other pole of the current consuming device 2I0 and in which is inserted a smoothening inductance coil II4.
To the make and break contacts are parallelconnected the current paths II5, I25, I35 respectively which may consist of ohmic or inductive or of capacitive resistor units or of any combination of such resistor units and which under certain conditions may be provided with the additional devices hereinafter described in connection with Figs. 2 to 4.
The movable bridge contacts I5I, I52, I53 perform in operation an upward movement which is brought about by tappets IGI, I62, I63 consisting of insulating material. The latter are under the influence of a spring I1I, I12, I13 respectively and are operated by cams I8I, I82, I03 which are firmly mounted on a shaft I08 and angularly displaced by 120 with respect to one another. The shaft I08 is mounted in the frame I90 and is driven by the synchronous motor I06 through an intermediate coupling I01. The synchronous motor is connected to the secondary winding 226 of an induction regulator whose primary side is connected to the output terminals The induction regulator'serves to vary the phase position of the rotating field of the driving motor I06; in this manner the moments at which the contacts are closed and opened are so adjusted that the opening of the contacts always occurs during the above explained weak current intervals in the neighborhood of the zero value of the current to be interrupted. On the shaft I08 are further arranged auxiliary circuit breakers 90 operating with current collectors (brushes) 95 which are held by supports 99 secured to the intermediate plate I20. The purpose and the op eration of the last-mentioned auxiliary circuit breakers are hereinafter described in connection with Fig. 4. By the simultaneous adjustment of the biasing current with the aid of the rheostat 300 and of the moments at which the contacts are opened and closed with the aid of the induction regulator 6, I26 a control of the current and the voltage may also be attained within wide limits (of. the above-mentioned copending application Serial No. 122,232),
In Fig. 2, 304 denotes the switching reactor with the magnet core 305 and the auxiliary biasing winding 3I1 which is connected to the directcurrent source I3I through the rheostat 360 and the reactor 35L The main conductor extends from the switching reactor 304 through circuit breaker 2 to the conductor I45 leading to the current consuming device 2I0 (not shown in Fig. 2).
In parallel relation to the make and break contacts lies as above mentioned an impedance arrangement II5. This arrangement consists of a condenser l and a low-ohmic resistor I5. In
the parallel path is further inserted an auxiliary switching reactor 504 which need only be rated for a small current, since the currents flowing through the parallel path amount to a fraction of the main current or only flow for a very short time. The magnet core 505 of the reactor 504 is also provided with a biasing winding denoted by the numeral 5H and connected to a battery '92 through a rheostat 560 and a reactor 56I. The direction of current of the magnetic bias is so adjusted as to exert a magnetic action in the same direction as the current flowing into the condenser I5 when opening the contacts. The magnitude of the exciting current is so adjusted that the core 505 of the switching-in coil is just saturated if no current flows in the main winding 504. The discharge current created when closing the contacts flows in the opposite direction through reactor 504 and counteracts the dlrect current magnetic bias. Consequently, the reactor becomes unsaturated shortly before the moment at which the contacts of breaker 2 are opened and assumes therefore a high resistance. The high inductive resistance prevents the capacitive discharge current from increasing until the contacts are firmly closed. In order to maintain the inductance of the reactor in the saturated state; i. e., the air inductance of its winding as small as possible very high-graded iron of very high permeability is preferably employed for the core 505 'of this auxiliary switching-in reactor as well as for the core 305 of the main switching reactor in order to reduce the number of turns to a minimum. As stated above with relation to the main switching reactor, such ferromagnetic material of extremely high permeability is employed, the characteristic of which has a sharp saturation bend.
Since for purely geometrical reasons it is difficult to attain a value below a predetermined limit value for the air inductance of the auxiliary switching-in reactor it is advisable to connect two or, if desired, also various of such switchingin reactors in parallel relation with one another in such cases where a very small air inductance, i. e., a very small resistance is required for the current flowing in the charging direction. To this end, a second auxiliary switching reactor 504a with the core 505a and the biasing winding 5I1a is provided in Fig. 2. The biasing windings BH and 5I1a are connected in series.
This arrangement may be advantageously employed not only in the manner as shown in the embodiment of Fig. 2 but also represents a valuable improvement in all switching devices of any arrangement, such as is, for instance, the case with rectifiers and inverters of difierent types, highly sensitive regulators and relays to which a condenser is connected in parallel relation for facilitating the switching out operations.
In the embodiment shown in Fig. 3 an auxiliary switching reactor 504 is not arranged in the parallel path but directly in series with the circuit breaker 2. The iron core 605 of this auxiliary switching reactor is provided with two auxiliary exciting windings H1 and M10. The exciting winding BI1 is fed by the battery I03 through a rheostat 650 and a reactor 65L The exciting winding 6I1a, is connected to an altermating-current source I95. The latter must have the same frequency as the alternating current taken from the main transformer. The exciting winding 6I1a may, for instance, be directly connectedif desired, through an auxiliary induction regulator 664 serving to accurately adjust the proper position of phase-to one of the secondary windings of the feeding main transformer itself which has the suitable position of phase for this purpose. Furthermore, in the auxiliary exciting circuit lies a rheostat 853 and another auxiliary switching reactor 104 with an iron'core 105. This auxiliary switching reactor 104 need only be rated for a very small current. Its iron core 105 has an additional exciting winding H1 which is fed from a battery I84 through a resistor I60 and a reactance coil IN.
The current flowing in the exciting winding BI! is so adjusted that the core 605 is biased in the opposite direction as by the main current. The magnitude of this exciting current is so adjusted with the aid of the rheostat 660 that the state of saturation is nearly attained by the biaseifected by winding 6H alone. If the main current begins to flow shortly after the contacts have been closed the switching reactor 604 has a very high resistance and consequently maintains the current at a low value until the state of saturation is attained when the current flows in the opposite direction. The exciting winding 6lla is not eiIective during this interval, for the magnitude and direction of the biasing current in the winding 1 l1 and the magnitude and phase position of the alternating current taken from the power source I85 are so chosen that the core 105 is unsaturated shortly before the closure of the contacts 2 so that the auxiliary switching reactor I04 has a very high resistance and the current flowing therein and therefore in the winding lil'la is practically zero. However, as soon as the contacts are closed the core 105 attains the state of saturation. In this manner the resistance of the switching coil 104 drops to a very low value. The switching reactor 104 permits therefore substantially without any hindrance the passage of the alternating current taken from the power source I95. The magnitude and the position of phase of this alternating current is so chosen that it exerts a magnetic effect. on the core 605 in the same direction as the main current in the switching reactor 604. The switching reactor 604 is therefore rendered ineffective by the alternating current during the period of the flow of current proper and during the time the main'contacts 2 are being separated.
In order to reduce also the voltage across the make and break contacts when switching in, a special parallel path is provided as shown in the embodiment according to Fig. 3 in which is inserted a low-ohmic resistor 624 and which is controlled byan auxiliary contact device 620. This auxiliary contact device consists of two stationary contacts 6 and a revolving part 65I which is driven in synchronism with the driving shaft for the main contact device and is so adjusted that it closesa parallel circuit shortly before the main contacts close. Since the auxiliary contact device 620 has only to carry a very small current momentarily and since a good contact is not essential insofar as also in the case of a relatively bad contact the resistance of the parallel path is always so small as to be neglected with respect to the resistance of the auxiliary switching reactor 4 which is at the same time in an unsaturated state, a slight consumption of the auxiliary contact device 620 may be put up without impairing the normal operation of the converter. Furthermore, the auxiliary contact may be made of a,material which is particularly resistant to arcing; for instance of tungsten. For the above-mentioned reasons it the main contacts.
As soon as the parallel path is closed by the auxiliary contact device 620, the total voltage distributes itself over the contact device 2 'and the auxiliary switching reactor 604 according to the ratio of the resistance of the parallel path in which the resistor 624 and the auxiliary switching device 620 are inserted, to the resistance of the auxiliary switching reactor 604 which is in an unsaturated state. Since the resistance of the parallel path amounts only to a fraction of the resistance of the unsaturated auxiliary reactor the voltage across the main contacts shortly before their closure is so small as to be neglected. An arcing will therefore not occur at the main contacts.
Also in the embodiment shown in Fig. 4 the auxiliary switching reactor 604 is connected in series with the interrupting device 2 and both are bridged by the parallel path through the resistance combination I I5 consisting of an ohmic resistor l5 and a condenser IS. The iron core 605 of the auxiliary switching reactor 604 carries an auxiliary winding 6" for effecting a magnetic bias. Winding 6|! is energized by the power source l83 through a reactor 66l and a rheostat 660. The magnetic bias is soadjusted that shortly before the engagement of the contacts l4l, Mia and IN the core 605 of the auxiliary switching reactor is in a nearly saturated state opposite to the direction of the main current which begins to flow through the auxiliary switching reactor 604 after the closure of the contacts. This main current therefore maintains practically the zero value until it has reversed the magnetization of the iron core and until the state of saturation is attained in the other direction. Only in this case themain current may flow through reactor 604 without hindrance. In order to maintain also the voltage between the contacts at a low value shortly before the engagement of the contacts, a further parallel path is directly parallel connected to the contacts I and I a, the resistance of this parallel path being small compared to the resistance of the auxiliary switching coil 604 which is at this moment in an unsaturated .state. The parallel path consists of a discharge tube 820 whose grid "I is connected through a high-ohmic resistor 82! to an auxiliary contact 24!, the closure of which leads. The .grid MI is biased by a battery I81 through a high-ohmic resistance 823. The cathode is heated by a heating battery I98. A protective resistor 824 is connected in series with the discharge tube 820. Instead of the resistance 824 also a condenser MS with a parallel-connected resistor 824 may be series-connected to the discharge tube. Another switching reactor 804 may be arranged in the lead to the discharge tube in order to protect the tube against a danger ous over-current. The iron core 805 of the reactor 804 is provided with an additional biasing winding 8|! which is energized by the direct current source l86 through a reactor "I and a rheostat 860. The magnetic bias is effected in a direction opposite to the direction of the current flowing normally through the discharge,
tube. The magnitude of the biasing current is so adjusted that the auxiliary switching reactor 804, 805 is highly saturated and permits the current to flow in normal operation through the discharge tube 820 without exceeding the saturation point In cases where considerably greater currents may occur which would stress and destroy the discharge tube the auxiliary switching reactor 804, 805 comes within the working range below the saturation so that such dangerous currents are prevented by the high inductive resistance of the unsaturated auxiliary switching reactor 804. If as above mentioned a condenser 8I5 with a parallel-connected ohmic resistance 824 is arranged in series with the auxiliary switching reactor 804 the condenser protects also the discharge tube even if themagnetization of the auxiliary switching coil 804, 805 has attained the saturation point in the opposite direction after reversal by the interfering current. The auxiliary reactor 804, 805, therefore, may be dimensioned smaller, as if the condenser 8I5 and the parallel resistor 824 were not available.
A resistor 808 having a high resistance may be parallel-connected to the auxiliary switching reactor 804 in order to facilitate the equalization of the magnetic energy when reversing the magnetism thereof.
The grid bias of the discharge tube 820 is adjusted to such a high value that the flow of current therethrough is prevented so long as the auxiliary contact 24I is not in engagement 7 with the movable contact I5I. The latter is connected to the stationary contact I4Ia by a flexible auxiliary conductor. As soon as it engages the preliminary contact 2 the grid inverse voltage will be reduced. The discharge tube 820 allows therefore a current to flow therethrough. Consequently, the voltage at the main contacts HI and I4Ia drops substantially to a value equal to the sum of the ignition voltage of the discharge tube 820 and of the voltage drop in the protective devices M5, 824, 804 and 808. This residual voltage across the contacts amounts only to a fraction of the total voltage which is substantially applied to the auxiliary switching reactor 604 being just unsaturated at this moment. Owing to the small residual voltage across the switching gap an arcing cannot occur across the contacts MI and I5I.
An advantageous arrangement of the leading auxiliary contact 24I is illustrated in Fig. 5 in which the contact device shown in Fig. 4 is illustrated on an enlarged scale. The contact device consists as shown in Fig. 1 of the stationary contacts I4I, I4Ia secured to the insulating plate I20. The movable contact I5I is under the influence of the spring I'II which presses against a second insulating plate I30. The drive is brought about by'the tappet IBI. The terminals for the leads are denoted by the numeral 245. The stationary contact MM is provided with a bore 242 in which moves the pin contact 2. The contact pin has a collar 246 and may be moved within a piston-shaped sleeve 243. The movement within this sleeve is limited by a stop 259 and an inner nut 240 which is adjustable by means of a fine thread 241. The collar 246 is pressed against the adjusting nut 248 by a spring 249. Upon the downward movement of the tappet I6I and the movable contact I5I the pin contact 24I is pressed down against the force of the spring 249. The piston-shaped sleeve 243 is movably arranged within a second sleeve 244 which is secured to the insulating plate I by means of an angle iron.254. The outer sleeve 244 is closed at both ends by covers 252 and 253 consisting of insulating material and being each provided with a bore. The bore of the cover 253 serves as'a guide for the contact pin 24I. Between the lower cover 252 and the piston-shaped sleeve 242 is arranged a weak spring 25I which tends to press the sleeve 242 in the upward direction. The movement is, however, damped by the air above the sleeve 243 and is limited by the engagement of the collar 245 of the contact pin 2 with the stop 259 upon the closure of the contacts. The piston-shaped sleeve 243 may therefore move in the upward direction during the operating period only gradually by the same amount as the upper end of the auxiliary contact 24I wears off with time. In this manner the contact pin 2 is automatically readjusted during the operating period by such an amount that its upper end projects beyond the contact surface of the stationary contact I4|m always the same length when opening the contacts. The length of this portion of the pin may be so adjusted with the aid of the adjusting nut 248 that the time interval which elapses between the engagement of the auxiliary contact 2 and the movable contact I5I and that of the movable contact I5! and the stationary main contact 14!, has the desired value. This value is maintained constant during the operation owing to the automatic adjustment by the spring 25I.
A conductor 25'! extends through the bore of the lower cover 252 from the contact pin 24I to the terminal-258. Another auxiliary conductor 251a extends from the movable contact I5I to the stationary contact I4Ia. Both auxiliary conductors carry only the current flowing in the grid circuit of the discharge tube 820 and are therefore very thin.
Furthermore, in Fig. 4 is provided a device by which the auxiliary switching reactor 604 is' short-circuited during the period of flow of current proper. This device consists of a contact device driven in synchronism with the shaft and of the brushes which are connected to the ends of the reactor 604 through conductors. The contact device 90 consists of two segments 9| which are directly connected to each other. Adjacent to each of these segments are arranged two short segments in the direction of rotation which are connected to the bridging segments 9| through the resistors 96 and 91. The short-circuit of the switching reactor is therefore not suddenly eliminated but a resistance is at first gradually inserted in the bridging short-circuit connection. In this manner the interruption of the short-circuit connection is rendered as sparkless as possible. Instead of connecting the short-circuit conductor of the brushes 95 directly to the ends of the auxiliary switching reactor 604 the latter may be provided according to Fig. 4a with an additional short-circuit winding 606 having a slight leakage to which the bridging contact device 90, 95 is connected.
As shown in Fig. l the revolving contact device 90 is mounted on the same shaft I08 as the driving cams for the contact device. The supports 99 for the brushes 95 are secured to the plate I20 of the insulating frame I90.
The invention may be embodied in other forms than those shown and described without departing from the scope of the invention.
What is claimed is:
1. An arrangement for converting alternating current into direct current or vice versa, or alternating current of one frequency into alternating current of another frequency, comprising a switching device having mechanically operated make and break contacts, means for simultaneously influencing thecurrent and voltage across the switching gap, said means comprising a switching reactor series-connected with said make andbreak contacts and designed to abruptly increase its impedance at small instantaneous values of the current in the neighborhood of its zero value, and a voltage-biasing impedance path parallel-connected to said make and break contacts for reducing the operating voltage recurring between said contacts, in combination with a variable auxiliary inductance designed to have a high resistance when switching in said'make and break contacts, said inductance being seriesconnected in a circuit including said make and break contacts and said parallel path.
- 2. A current converting arrangement comprising a switching device having mechanically operated make and break contacts, means for simultaneously influencing the current and voltage across the switching gap, said means comprising an inductance coil series-connected with said contacts and having a magnetic core designed to become abruptly unsaturated at current intensities near the zero value and of a current path including capacitors arranged in parallel to said make and break contacts for reducing the operating voltage recurring between said contacts, in combination with an auxiliary switching-in reactor connected in series with the make and break contacts in the circuit including said contacts and said parallel path, said switching-in reactor having a magnet core designed to be unsaturated only at small instantaneous current values in the neighborhood of the zero value and to become saturated upon the instantaneous current exceeding a given value which amounts to a fraction of the mean current carried by said switching-in reactor in the state of saturation.
3. A current converting arrangement comprising a switching device having mechanically operated make and break contacts, means for simultaneously influencing the current and voltage across the switching gap, said means comprising a current-biasing reactor series-connected to said make and break contacts and a voltage-biasing current path parallel-connected to said make and break contacts for reducing the operating voltage recurring between said contacts, in combination with an auxiliary switching-in reactor connected in series with said make and break contacts in the circuit including said make and break contacts and said parallel path, said switching-in reactor having a magnet core designed to become abruptly unsaturated upon the lowering of the instantaneous current intensity to values in the neighborhood of the zero value, a biasing winding arranged on the core of said switching-in reactor, and a biasing circuit connected to said winding, said circuit including an auxiliary current source and variable means for controlling the magnetic bias effected by said winding.
4. A current converting arrangement comprising a switching device having mechanically operated make and break contacts,'means for simultaneously influencing the current and voltage across the switching gap, said means comprising a current-biasing reactor series-connected to said make and break contacts and designed to periodically increase its reactance at low current intensities, and a voltage-biasing current path parparallel path, said switching-in reactor having a magnet core designed to become abruptly unsaturated upon the lowering of the instantaneous current intensity to values in the neighborhood of the zero value, a biasing winding disposed on the core of said switching-in reactor, a biasing circuit connected to said winding, an alternating current source having the frequency of the current to be interrupted by said contacts, said source being connected in said biasing circuit, and means in said circuit for controlling the phase position of the biasing current with respect to the phase position of said current to be interrupted.
5. A current converting arrangement comprising a switching device having mechanically operated make and break contacts, means for simultaneously influencing the current and voltage across the switching gap, said means comprising 4 a current-biasing reactor series-connected to said make and break contacts and designed to periodically increase its reactance at low current intensities, and avoltage-biasing current path parallel-connected to said make and break contacts for reducing the operating voltage recurring between said contacts, in combination with an auxiliary switching-in reactor connected in series with said make and break contacts in the circuit including said make 'and break contacts and said parallel path, said switching-in reactor having a magnet core designed to become abruptly unsaturated upon the lowering of the instantaneous current intensity to values in the neighborhood of the zero value, a biasing winding arranged on the core of said switching-in reactor, and an energizing circuit connected to said winding, said circuit being so adjusted that said switching-in reactor is in the state of saturation upon the opening of said break and make contacts.
6. In combination with a device for closing and opening an alternating current circuit, a switching reactor having an inductance winding seriesconnected with said device so as to be traversed by the alternating current to be'controlled by said device and a magnet core designed to be uncore, a second switching reactor having a main winding connected with said auxiliary biasing winding of said first reactor and a magnet core also designed to be unsaturated at said small instantaneous current intensities and saturated upon exceeding a predetermined intensity amounting to a fraction of the normal mean operating current flowing through said main winding of said second reactor, a biasing winding disposed on the core of said second reactor, and an energizing circuit connected with said latter biasing winding, said energizing circuit being adjusted to cause said second reactor to have in a iven interval within each cycle of said alternatn current an increased inductive resistance so that in said interval the auxiliary biasing current controlling said first reactor has a minimum value.
'7. A current converting arrangement comprising a switching device having mechanically operated make and break contacts, means for simultaneously influencing the current and voltage across the switching gap, said means comprising a self-saturating switching reactor seriesconnected to said make and break contacts for decreasing the current intensities in the neighborhood of the passage of the current through its zero value and voltage-biasing means connected in parallel to said make and break contacts and being provided with a variable auxiliary impedance designed to have an increased impedance value when switching in said make and break contacts, and an auxiliary contact device for bridging said auxiliary impedance during a given interval within each current cycle, said interval including at least the'period of the opening oi said contacts.
8. A current converting arrangement comprising a switching device having mechanically operated make and break contacts, means for simultaneously influencing the current and voltage across the switching gap, said means comprising a self-saturating switching reactor series-connected to said make and break contacts for decreasing the current intensities in the neighborhood of the passage of the current through its zero value and voltage-biasing means connected in parallel to said make and break contacts and being provided with a variable auxiliary impedance designed to have an increased impedance value when switching in said make and break contacts, an auxiliary contact device for br dging said auxiliary impedance, and means for operating said auxiliary contact device.
9. A current converting arrangement comprising a switching device having mechanically operated make and break contacts, means for simultaneously influencing the current and voltage across the switching gap, said means comprising a self-saturating switching reactor series-connected to said make and break contacts for decreasing the current intensities in the neighborhood of the passage of the current through its zero value and voltage-biasing means connected in parallel to said make and break contacts and being provided with an auxiliary switching reactor designed to have an increased resistance when switching in said make and break contacts, said auxiliary reactor having a magnet core and an additional biasing winding arranged on said core so as to have a slight leakage, and an auxiliary contact device for bridging said additional winding during the opening of said make and break contacts.
10. A current converting arrangement comprising a switching device having mechanically operated make and break contacts, means for simultaneously influencing the current and voltage across the switching gap, said means comprising a self-saturating switching reactor series-connected to said make and break contacts for decreasing the' current intensities in the neighborhood of the passage of the current through its zero value and voltage-biasing means connected in parallel to said make and break contacts and being provided with a variable auxiliary impedance designed to have an increased impedance value when switching in said make and break contacts, a parallel path containing current-limiting impedances. said path being arranged in parallel to said make and break contacts in order to reduce the voltage prevailing across the switching gap between said contacts, and means for connecting said parallel path with said make and break contacts shortly before their closure.
11. A current converting arrangement comprising a switching device having mechanically operated make and break contacts, means for simultaneously influencing the current and voltage across the switching gap, said means comprising a self-saturating switching reactor series-connected to said make and break contacts for decreasing the current intensities in the neighborhood of the passage of the current through its zero value and voltage-biasing means connected in parallel to said make and break contacts and being provided with a variable auxiliary impedance designed to have an increased impedance value when switching in said make and break contacts, a parallel path containing current-limiting impedances, said path being arranged in parallel to said make and break contacts in order to reduce the voltage prevailing across the switching gap between said contacts, an auxiliary contact device for closing said parallel path shortly before the closure of said make and break contacts, and means for operating said auxiliary contact device in synchronism with said switching device.
12. A converting arrangement comprising a switching device having mechanically operated contacts. means for simultaneously influencing the current and voltage across the switching gap, said means consisting of a current-biasing selfsaturating switching reactor series-connected to said contacts and of a voltage-biasing path parallel-connected to said contacts, said means being further provided with a variable auxiliary impedance having a high impedance value when closing said contacts, a second parallel path including current-limiting devices and being directly parallel-connected to the make and break contacts in order to reduce the voltage prevailing across the switching gap between said contacts, said second parallel path containing a grid controlled discharge tube, an auxiliary current source connected in the grid circuit of said tube for supplying a blocking voltage to said grid, an auxiliary contact device connected with said grid circuit so as to diminish when operated said grid voltage in order to allow a current flow through said tube, and means for operating said auxiliary contact device in synchronism with said switching device so as to be actuated shortly before the closure of the contacts of said switching device.
13. A converting arrangement comprising a switching device having mechanically operated make and break contacts, means for simultaneously influencing the current and voltage across the switching gap, said means consisting of a self-saturating switching reactor series-connected to the make and break contacts and of a voltage-biasing path parallel-connected to said make and break contacts, and being provided with a variable auxiliary impedance having a high impedance value when closing the make and break contacts, an automatic device for bridging said make and break contacts shortly before their closure through a second parallel path including current-limiting impedances and being directly parallel-connected to said make and break contacts in order to reduce the voltage prevailing across the switching gap. said bridging device comprising a grid controlled discharge tube, an ohmic resistance series-connected with said tube for protecting said tube against overload in case of disturbances, and means for controlling the grid voltage of said tube in dependency upon the operation of said make and break contacts.
14. A converting arrangement comprising a switching device having mechanically operated make and break contacts, means for simultaneously influencing the current and voltage across the switching gap, said means consisting of a self-saturating switching reactor series-connected to said make and break contacts and of a cur- (iii rent path parallel-connected to the make and break contacts, and being provided with a variable auxiliary impedance having a high impedance value when closing said make and break contacts, a device for bridging said make and break contacts shortly before their closure through a second parallel path including ourrent-limiting devices and being directly parallelconnected to said make and break contacts in order to reduce the voltage prevailing across the switching gap, said bridging device comprising a grid controlled discharge tube, a parallel-connection disposed in series with said tube and including a condenser and an ohmic resistor for protecting said tube against overload in case of disturbances, and means for controlling said tube in dependency upon the operation of said make and break contacts.
15. A converting arrangement comprising a switching device having mechanically operated make and break contacts, means for simultaneously influencing the current and voltage across the switching gap, said means consisting of a self-saturating switching reactor series-connected to said make and break contacts and of a current path parallel-connected to said make and break contacts, and being provided with an auxiliary switchingein reactor having a high resistance when closing said make and break contacts, a device for bridging said make and break contacts shortly before their closure through a second parallel path including current-limiting devices and being directly parallel-connected to said make and break contacts in order to reduce the voltage prevailing across the switching gap, a grid controlled discharge tube arranged in said second parallel path, an auxiliary switching reactor having a main winding series-connected with said tube and a magnet core designed to become unsaturated at low current intensities near the zero value, a biasing winding on said core, and an energizing circuit connected with said biasing winding, said energizing current being adapted to supply said biasing winding with a current acting in opposition to the current flowing through said tube and magnetizing said core to such an extent beyond itssaturation point that said current flowing through said tube during normal operation does not cause said. magnetization to drop below said saturation point.
16. A converting arrangement comprising a switching device having mechanically operated main contacts, means for simultaneously influencing the current and voltage across the switch ing gap, said means consisting of a self-saturating switching reactor series-connected to said contacts and of a current path parallel-connected to said contacts, and being provided with a variable auxiliary impedance having a high impedance value when closing said contacts, an impedance arrangement disposed in parallel to said contacts and designed to bridge the switching gap shortly before each closure of said contacts, an auxiliary contact device for controlling said bridging arrangement, said contact device consisting of a contact pin movably disposed in a bore of a stationary contact of said main contacts so as to protrude from the contact surface of said stationary main contact in order to cooperate with the movable countercontact of said stationary main contact, spring means for holding said pin in said protruding position, and an adjustable stop for securing said position.
17. A' converting arrangement comprising a switching device having mechanically operated main contacts, means for simultaneously influencing the current and voltage across the switching gap, said means consisting of a self-saturating switching reactor'series-connected to said contacts and of a current path parallel-connected to 5 said contacts, and being provided with a variable auxiliary impedance having a high impedance value when closing said contacts, an impedance arrangement disposed in parallel to said contacts and designed to bridge the switching gap shortly before each closure of said contacts, an auxiliary contact device for controlling said bridging arrangement, said auxiliary contact device having a pin movably arranged in a bore of a stationary main contact so as to protrude from said contact in order to cooperate with the movable countercontact of said stationary main contact, a pistonshaped sleeve movably disposed on said pin and connected with said pin by a spring and an adjustable stop arrangement for limiting the rein-- tive movements between said sleeve and said pin, a stationary air cylinder surrounding said sleeve and designed for dampening the movements of said sleeve, and a spring disposed between said cylinder and said sleeve for holding said sleeve and said pin in operative position.
18. With a device for opening and closing an alternating current circuit at a moment of predetermined phase position with respect to the cycle of said current, in combination, voltage-biasing means connected in parallel to said device for reducing the increase of the operating voltage recurring at the opening moment across said device, an inductance coil connected in a circuit including in series said device and said means, said coil being provided with a core of ferromagnetic material having a high permeability and a magnetization curve with a sharp saturation bend, a biasing winding disposed on said core, and an energizing circuit connected with said winding and adapted to cause a desaturating bias of said core shortly before the closing moment of said device, thereby abruptly increasing the inductance of said coil.
19. With a contact device for opening and closing an alternating current circuit in a given time relation to the cycle of said current, said device being adjusted to effect said opening at a moment in the neighborhood of the zero value of said current, in combination, means connected with said circuit for distorting the curve of said current so as to producea weak current interval including said opening'rnoment, voltage-biasing means connected in parallel to said device for reducing the increase of the operating voltage recurring at the opening moment across said device, an inductance coil connected in a circuit including in series said device and said means, said coil being provided with a core of ferromagnetic material having a high permeability and a so magnetization curve with a sharp saturation bend, a biasing winding disposed on said core, and an energizing circuit connected with said winding and adapted to cause a desaturating bias of said core shortly before the closing moment of 05 said device, thereby abruptly increasing the inductance of said coil.
20. With a contactdevice for periodically opening and closing an alternating current circuit in synchronism with the cycle of said current, said 7 device being adjusted to efl'ect said opening at a moment in the neighborhood of the zero value of said current, in combination, a periodically variable impedance connected in said circuit and designed to increase its impedance value during an interval including said opening moment, a reactive impedance path connected in parallel to the gap of said contact device for decreasing the voltage across said gap during the opening operation, an inductance coil series-connected in the circuit including said gap and said parallel path, said coil being provided with a core of ferromagnetic material having a high permeability and a magnetization curve with a sharp satin ation bend, a biasing winding disposed on said core, and a biasing circuit connected with said winding and adapted to control the state of magnetization of said core and thereby the inductance of said coil shortly before the contact closing moment of said device in order to counteract the sparking tendency caused by said parallel path during the closing operation of said device.
21. With a device for opening and closing an alternating current circuit in a given time relation to the cycle of said current, said device being adjusted to eifect said opening at a moment in the neighborhood of the zero value of said current, in combination, means connected with said circuit for distorting the curve of said current so as to produce a weak current interval including said opening moment, a capacitive path connected in parallel to said device for decreasing the voltage across said device during the opening operation, an inductance coil series-connected in the circuit including in series said device and said parallel path, said coil being provided with a core of ferromagnetic material having a high permeability and a magnetization curve with a sharp saturation bend, a biasing winding disposed on said core, and a biasing circuit connected with said winding and adapted to control the state of magnetization 01' said core and thereby the inductance of said coil shortly before the closing moment of said device in order to impede the capacitive discharge current of said path during the closing operation of said device.
22. With a device for opening and closing an allel path, said coil being provided with a core of ferromagnetic material having a high permea bility and a magnetization curve with a sharp saturation bend, a biasing winding disposed on said core, and a biasing circuit connected with said winding, and adapted to control the state of magnetization of said core and thereby the inductance of said coil shortly before the closing moment of said device in order to impede the capacitive discharge current of said path during the closing operation of said device.
23. With a contact device for opening and closing an alternating current circuit in a given time relation to the cycle of said current, said device being adjusted to eiiect said opening at a mo ment in the neighborhood of the zero value of said current, in combination, means connected with said circuit for distorting the curve of said current so as to produce a weak current interval including said opening moment, a reactive path connected in parallel to the gap of said contact device for decreasing the voltage across said gap during the opening operation of said device, a variable impedance series-connected in the circuit including said gap and said parallel path, controlling means for causing said variable impedance to vary its impedance value shortly before the contact closure of said device so as to counteract the sparking tendency caused by said parallel path at the closing moment of said device.
24. A current converting arrangement comprising a switching device having periodically operating make and break contacts, a saturable reactor series connected to said contacts for periodically producing a weak current interval at low current intensities, means for controlling said reactor to effect said weak current interval in a desired time relation to the operation of said switching device, a second saturable reactor having one pole connected with one of said contacts and the other pole connected with the other contact of said switching device so as to form part of a parallel circuit with respect to the switching gap between said contacts, and means for controlling said second reactor to cause said reactor to increase its reactance shortly before the closing moment of said contacts.
FLORIS KOPPELM'ANN.
US16742237 1936-10-05 1937-10-05 Apparatus for converting currents Expired - Lifetime US2188361A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2188361X 1936-10-05

Publications (1)

Publication Number Publication Date
US2188361A true US2188361A (en) 1940-01-30

Family

ID=7989221

Family Applications (1)

Application Number Title Priority Date Filing Date
US16742237 Expired - Lifetime US2188361A (en) 1936-10-05 1937-10-05 Apparatus for converting currents

Country Status (1)

Country Link
US (1) US2188361A (en)

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2466864A (en) * 1943-06-22 1949-04-12 Bbc Brown Boveri & Cie Mechanical converter
US2493403A (en) * 1948-01-27 1950-01-03 Klaus L Hansen Synchronous rectifier and inverter
US2557739A (en) * 1945-04-25 1951-06-19 Bbc Brown Boveri & Cie Apparatus for controlling the timing of periodically actuated switches of mechanicalcurrent converters
US2595024A (en) * 1948-01-19 1952-04-29 Products & Licensing Corp Contact arc suppression
US2622234A (en) * 1949-01-20 1952-12-16 Bbc Brown Boveri & Cie Mechanical current converter with apparatus for monitoring the synchronously actuated switches
US2650305A (en) * 1945-01-31 1953-08-25 Products & Licensing Corp Converter and other electrical apparatus with rotary commutators
US2651750A (en) * 1950-02-21 1953-09-08 Licentia Gmbh Mechanical rectifier
US2654063A (en) * 1948-06-05 1953-09-29 Arthur M Cohen Synchronously operated regulator
US2693569A (en) * 1951-02-21 1954-11-02 Ite Circuit Breaker Ltd Commutating reactor
US2854616A (en) * 1954-11-15 1958-09-30 Siemens Ag Flux reversal circuits for mechanical rectifiers
US2859401A (en) * 1955-02-04 1958-11-04 Siemens Ag Flux reversal circuits for rectifiers
US2880386A (en) * 1954-11-17 1959-03-31 Siemens Ag Flux reversal circuit for rectifiers
US2880387A (en) * 1954-11-30 1959-03-31 Siemens Ag Flux reversal circuit for rectifiers
US2895101A (en) * 1956-05-24 1959-07-14 Bbc Brown Boveri & Cie Voltage regulation arrangement for contact converters

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2466864A (en) * 1943-06-22 1949-04-12 Bbc Brown Boveri & Cie Mechanical converter
US2650305A (en) * 1945-01-31 1953-08-25 Products & Licensing Corp Converter and other electrical apparatus with rotary commutators
US2557739A (en) * 1945-04-25 1951-06-19 Bbc Brown Boveri & Cie Apparatus for controlling the timing of periodically actuated switches of mechanicalcurrent converters
US2595024A (en) * 1948-01-19 1952-04-29 Products & Licensing Corp Contact arc suppression
US2493403A (en) * 1948-01-27 1950-01-03 Klaus L Hansen Synchronous rectifier and inverter
US2654063A (en) * 1948-06-05 1953-09-29 Arthur M Cohen Synchronously operated regulator
US2622234A (en) * 1949-01-20 1952-12-16 Bbc Brown Boveri & Cie Mechanical current converter with apparatus for monitoring the synchronously actuated switches
US2651750A (en) * 1950-02-21 1953-09-08 Licentia Gmbh Mechanical rectifier
US2693569A (en) * 1951-02-21 1954-11-02 Ite Circuit Breaker Ltd Commutating reactor
US2854616A (en) * 1954-11-15 1958-09-30 Siemens Ag Flux reversal circuits for mechanical rectifiers
US2880386A (en) * 1954-11-17 1959-03-31 Siemens Ag Flux reversal circuit for rectifiers
US2880387A (en) * 1954-11-30 1959-03-31 Siemens Ag Flux reversal circuit for rectifiers
US2859401A (en) * 1955-02-04 1958-11-04 Siemens Ag Flux reversal circuits for rectifiers
US2895101A (en) * 1956-05-24 1959-07-14 Bbc Brown Boveri & Cie Voltage regulation arrangement for contact converters

Similar Documents

Publication Publication Date Title
US2188361A (en) Apparatus for converting currents
US2849659A (en) Direct-current and alternatingcurrent circuit interrupters
US1966077A (en) Surge absorbing apparatus
US2843763A (en) Apparatus for the switching of electric power circuits without contacts
US2351975A (en) Apparatus for interrupting alternating currents
US2375609A (en) Arrangement for protecting circuit breakers
US2276784A (en) Converter and rectifier
US3829736A (en) Reactive energy static compensator to protect thyristor rectifiers
US2619628A (en) Converter with electromagnetic switches
US2499394A (en) Electric contact apparatus
US2151753A (en) Circuit arrangement for protecting electric discharge apparatus systems
US2568140A (en) Synchronous switching apparatus for electric circuits
US3124740A (en) Stage
US3260894A (en) Protective means for circuit interrupting devices
US2372134A (en) Protective relay system
US2584535A (en) System for reducing contact arcing in synchronous switching apparatus
US2201829A (en) Protective apparatus
US2547614A (en) Saturable reactor arc prevention circuit
US2195818A (en) Apparatus for converting currents
US1696177A (en) System of distribution
US2756380A (en) Electromagnetic switch
US2693569A (en) Commutating reactor
US1817526A (en) Protective system
US1480857A (en) Electric-arc-welding system
US1919980A (en) Control of electric circuits