US1654949A

US1654949A - Current-regulating arrangement for rectifiers

Info

Publication number: US1654949A
Authority: US
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1923-01-05
Filing date: 1923-12-21
Publication date: 1928-01-03
Anticipated expiration: 1945-01-03
Also published as: FR574515A; DE415910C; GB209426A

Description

Jan. 3, 1928.

P. M. G. TQuLoN CURRENT REGULATING ARRANGEMENT FOR RBCTIFIERS FlecLDec. 21. 1923 5 Sheets-Sheet l Jan. 3, 1928. f

P. M. G. TOULQN CURRENT REGULATING ARRANGEHENT Fon REcTIFIERs Filed Deo. 21./1923 i Sheets-Sheet 2 Jan. 3, 192s. 1,654,949

P. M. G. TOULON 1 CURRENTREGULATING ARRANGEMENT FOR RECTIFIERS Patented Jan. 3, 1928. y

UNITED STATES l 1,654,949 PATENT oFFIcE.

PIERRE MARIE GABRIEL TOULON, OF PARIS, FRANCE, ASSIGNOR, BY IIESNE ASSIGN- MENTS, TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

CURRENT-REGULATING ARRANGEMENT FOR RECTII'ZIERS.

Application led December 2 1, 1923, Serial No. 682,093, and in Germany January 4, 1923.'

My invention relates to current rectifiers wherein the current passing through the same will produce an aro between an incandescent cathode (iilament placed in a raren fied gas such as neon or argon) and raised to incandescent by the passave of a current, or a bath of liquid metal I(for example a bath of mercury with cathodic spot maintained by a small auxiliary arc), and one or In more anodes. It has for its object to permit of regulating and continuously varying the rectified current.

In three-electrode vacuum tubes one may pass between the filament and the plate a l5 current whose value is regulated by varying the potential of the grid. By analogy, it has been proposed for arc apparatus of the above-mentioned type, to place in thepath of the arc a cooled grid whose potential can 2U be varied in order to influence the current passing through the rectifier; it has been further proposed to place around the apparatus the conducting body whose potential is varied in order to act upon the current in an electrostatic manner and to regulate its value. The apparatus which can be thus devised may be employed for example as converting apparatus, amplifiers, or genera-- tors of current of high or low frequency, according to the knowny dispositions. In these vapor electric apparatus, the electrostatic action can advance or retard the formation of the arc. But when the arc is once formed between the cathode and an anode, it is impossible to extinguish it by means of said electro-static action. It is a sort of mishit regulation. It will follow that with the devices hitherto in use, one cannot completely varyat will in a progressive manner the value of the current supplied by an anode. In particular, when the apparatus is supplied from a source of alternating current and operates as in a rectifier or an amplify-.1'-

ing device, it becomes impossible to obtain the desired voltage and current in the work circuit.

This drawback does not occur with the three-electrode tubes and it is in fact recognized that by varying the potential of the grid one can modify in a continuous manner the value of the current between the filament to the plate. But on the other -hand the three-electrode .tubes will not render the same services as the vapor electric or are 5 apparatus, for they can only supply a relatively small current, even for large-Sized bulbs, wlule the fall of tension in the em ty space between filament and plate is consi l erable, andthe efficiency is low.

My said invention has for its object, by obviatmg the above-mentioned drawback, to render feasible for the arc apparatus fed by alternating current nearly all the arrangements .and most of 'the applications which were hltherto restricted to the three-electrode tubes.

u The invention consists in providing an lnner or outer conducting body acting electrostatically upon the electric charges adjacent one of electrodes of apparatus not with ,a potential, as heretofore, either constant or else, if alternating, in phase with potential of correspondlng electrode or showing with same a constant phase difference, but on the y contrary with an alternating potential showing with potential of corresponding electrode a phase difference which can be varied at will, so that the arc cannot be formed during a determined fraction of the half period in which the corresponding anode is positive. The invention is obviously applicable to a plurality of electrodes at the same time. The phase difference may be regulated so that the arc of any given anode shall only remain active, in each period, between two instants which can be determined at will, and it thus becomes feasible to var in a progressive manner the current supp ied by the anode, as well as the potential difference of the rectified current. The said device offers the means for obtaining not only an amplifier whose characteristic curve does not possess the abrupt bend which results from vthe known arrangements, but further, by a suitable disposition, a voltage regulator or transformer, a starting rheostat, a frequencyreducing transformer and a phase compensator, as will be made evident in the several applications of the saine which vare disclosed hereunder by way of example.

The variable phase-difference between the potential of an anode and that of the inner or outer body which acts electrostatically thereon is obtained by any suitable means, and chiefly by the use of windings properly disposed in a polyphase revolving eld analogous to what prevails for synchronous or non-synchronous motors or by means of resistances, self-induction or capacities, according to known devices.

By way of example I have described hereunder and illustrated in the appended drawing various applications of the invention.

Fig. 1 relates to an apparatus having a single anode. The arrangement indicated may be used to advantage as an amplifier or a voltage regulator. The phase displacement of this tension is effected by means of a variable self-induction. 0

Fig. 2 is a diagram showing the variations of potential and current in relation to the time, in the anode-of the above-mentioned apparatus, and the phenomena can be thus explained.

Fig. 3 relates to the use of a two-anode bulb. y

Fig. 4 relates to the case of an apparatus having a great number of anodes supplied from a polyphase source; this device is chiefly advantageous in providing a frequency changing apparatus or a phase compensator.

Fig. 5 is a diagram relating to Fig. 4, showing the tension and current in each anode, whereby the phenomena can be explained.

Fig. 6 relates to the case in which various cathodes are mounted in t-he bulb, whereby the directionof the current can be reversed at will.

Among the arrangements which the invention affords, the dispositions which are set forth hereunder are only intended to represent a few of the most interesting devices, and obviously I may provide many others which are of a different nature while at the same time conforming to the spirit of the invention. Y

As shown in Fig. 1, the bulb l1 contains a mercury cathode 2 upon which a cathodic spot is maintained by means of an auxiliary electrode 3 supplied from a continuous

current source

4, 4 through an adjustable resistence 5. The mercury anode 6 is connected to an alternating current line 8, 8 (whose source 8 is between 8 and 8) through the work circuit 7 comprising the apparatus A. A coating 9 which surrounds the anode 6 and exercises an electrostatic action upon the elect-ric charges is connected to the cathode through the resistance 10, and to the other terminal of the alternating current line 8 through the primary of a small transformer 11 whose self-induction may be varied by progressively short-circuiting the secondary upon a small variable resistance 12. The transformer 11 ina be replaced by a variable self-induction coil. The bulb is preferably cooled by immersing it in an insulating liquid13 such as oil. An analogous arrangement can be used with an arcappa` ratus comprising a cooled grid placed in the path of the are.

s The current necessary to vary the potential of the coating 9 is extremely small with reference to the current in the external circuit 7, so that the resistance 10 and the selfinduct-ion l1 can be made very high without inconvenience. Since the current therein has very small value, they may have a greatly reduced size. Further, the tension of the secondary circuit of the transformer 11 can be suitably chosen to enable an economical construction of the rheostat 12 which has on the other hand the advantage of being electrically insulated from t e rest of the device.

The operation is as follows. The cathode is made active and is maintained in operation by the electrode 3. The curve 14, Fig. 2, shows the potential difference between the cathode 2 and the anode 6 in relation to the time. The lower curve 20 shows the value which the alternating current would attain if it' could pass without interruption through the appaiataus whose resistance is constant. Curve 15 represents the potential difference between the cathode 2 and the coating 9. The phase diierence between the two sinusoids 14 and 15, i. e. the distance 16-17, can be continuously modified by acting upon the rheostat 12. As long as the potential lof the coating 9 with reference to the cathode 2 is below a certain value reprel sented b the horizontal line 18, the arc can` not be formed between the anode and the cathode. When this potential 18 is attained at 18', the are will be formed, and the potential diiference between anode and cathode (curve 14) has a value 19 which is low and is substantially constant (about 11 volts for a mercury are); this potential difference is represented by the horizontal line 19. At the same time the value 2O of the current in the anode (lower curve)y which was practically nil at 20 will rise abruptly to a rather high value 20 depending -upon the phase difference and the self-induction of the circuit. In Fig. 2 it is supposed that the work circuit has no self-induction, so that after the lighting of the the arc takes place, the current will vary according to a

sinusoid

20, 20 until the supply tension (curve 14) at the point 19 becomes less than the tension 19 which must prevail between the electrodes for the maintenace of the arc, and hence they arc will be extinguished. 'Ihe same effects will occur at eachI alteration.

Fig. 3 shows an arrangement with tivo anodes. The supply transformer 21 having a middle neutral point supplies the external work circuit 22. This circuit is connected to the cathode 23 whose cathodic spot is maintained by the auxiliary anode 24. The

anodes

25, 26 are supplied by the transformer andare connected to its two ends 21', 21". The

coatings

27, 28, connected at 21 to the neutral point of the transformer 21, will have an electrostatic action upon the free electric charges and Will retardl the lighting. Their lou . that for certain tubes and with an excessive pressure of the mercury vapor, it will be impossible to regulate the current supplied, and that the are will not become extinguished. This drawback can usually be obviated by mounting additional coatings such as 33, 34 along the walls, and said coatings will be connected to the neutral point at 2 1 (connection shown in full lines) or to the cathode at 23 (connection in dotted lines) or further, the coating 33 can be raised to a potential having a negative phase-diiference with re-vv spect to the anode, for instance by connecting it to 26, and a like effect `can be obtained for the coating 34 by connecting it to 25. By properly choosing the phases of the potentials and of the coatings, and also the shape of the tube, it will be almost always feasible to find the critical region in which the unstable condition of the arc will allow the regulating of the current produced, in accordance with the invention.

Fig. 4 relates to the use of a polyphase converting device having six anodes,. The secondary of the 6-phase transformer 35 supplies the six

anodes

36, 37, 38, 39, 40, 41 each of which is provided with a rcoating such as 42 (the coating may be replaced by a grid) having an electrostatic action upon the electric charges. The cathode 43, which is maintained by means of the auxiliary electrode 44, is connected to the neutral point of the main line through the medium of the work circuit 45 a-ccording to one of the known arrangements for mercury vapor converting devices. Further, by the use of various ends brought out, or additional windings on the polyphase transformer, one can produce in a n'iagnetic circuit ofv small size 46 a rotating ticld analogous to those produced in motors, for instance by the use of the

coils

47, 48, 49. The phase of the tension of any one of the coatings surrounding the anodes, such as 42, can be varied by changing the position of itssupply coil in relation tc the other

stationary coils

47, 48, 49 producing the rotating field. The six coils Y (such as 50) which supply the six coatings 42 may be mounted with a single movable core so as to constitute windings which are analogous to the armature sections of a I of the core.

dynamo.l One can thus produce gradual variations in the current by slightly rotating the movable core in the revolving field. By actuating the said core in a continuous manner at al given speed, a pulsating current of variable vfrequency will be produced in the work circuit., thus forming a frequency changing device. The arrangement can be colnpleted by the use of various apparatus analogous to the one above described, whereby a polyphase system will be obtained; for instance by the use of three apparata I may constitute a three-phase system operating at the new frequency. The said movable core which has thereon the windings 30 and whose variations ot' position change the potential of the coatings 42, may comprise all the windings at once by a suitable disposition of the several coils, as may be readily conceived.

Further the said revolving field arrangement for the device controlling the coatings employing the

coils

47, 48, 49, may be provided with all the improvements which are known in the case of multiple windings for dynamos or stators having a certain number of poles, and it is subject to a considerable range of variations.

The problem of constituting, in accordance with the invention, a phase compensator or various devices for increasing the power factor, .may be solved in a very simple manner by a suitable choice of the potentials of the coatings. It will suiiice to select this potential in such manner that the output of each anode shall be in advance upon the maximum tension of the supply transformer.

According to the invention, apparatus may be constructed for the automatic comloo pensation of the drop in voltage on the lines y of a main supply circuit. As I have already shown, it is feasible to vary at will and in a continuous manner the voltage or the current in the circuit supplied by the said apparatus, by changing the value of a self-induction or of a resistance suitably connected to the coating (or grid) or acting 'directly thereupon. Itis evident that this variation can be controlled by the displacement of a movable coil of a galvanometer which serves as a voltmeter or an ameter. It is also known that the value of the self-induction of a coil with iron core will vary with the saturation This saturation varies with the magnetizingcurrent acting upon the core. It will. be an easy matter to obtain cause and el'ect relations between such phenomena by means of suitable arrangements of apparatus and circuits. For instance 'I may automatically increase the line voltage inv l relation to the output, andl obtain what is often designated as compounding, by ena-` ploying the line current itselflto saturate the core of the self-inductionfcoil by the proper disposition of "windings thereon. This self-induction coil will regulate the line voltage by acting upon the coatings (or grid) by an arrangement of circuits and devices as above indicated.

The operation of the converting apparatus indicated in Fig. 4 as a voltage regulator or starting rheostat is shown diagrammatically in Fig. 5, which represents at the upper part the six sinusoids of the G-phase circuit, these being displaced in phase. The lower sinusoid 5l represents the potential difference between the neutral point and one of the anodes. The toothed curve 52 (full lines) at the top, represent the value of the current produced. The curve with flat parts 53 (full lines) at the bottom, represents the potential difference between an anode and the cathode. The curve 54.- represents the potential difference between the cathode and the coatings.

The operation of the device will be readily understood with reference to the explanations given for the apparatus Fig. 2.

As long as the potential of 54 (dil'eren'fe between the cathode and coating) is below a certain critical value 54, the anode (such as 3l) cannot be lighted. But when the said value is attained, the anode becomes lighted and it will remain lighted until the succeeding electrode can be lighted in turn due to the value of the potential of its coating. Fig. 6 shows a special arrangement applicable to the case in which the converting device comprises a plurality of cathodes, two for instance, enabling the reversal of the current in the bulb at will at any given moment, and also the regulation of the value of this current. Eachoi the

cathodes

55, 56 are maintained by two

auxiliary electrodes

57, 58 supplied by small independent continuous current sources. The

coatings

59, 60 allow of preventing the formation of the-arc in one or the other direction. For this purpose the coating 59 is connected to the cathode 56 through a winding 62 producing a. certain E. M. F. which is variable in current and in phase. In like manner, 6() is connected to 55 through a winding 61 which produces a certain E. M. F. variable in current and in phase. The

coils

61 and 62 can be moved in the revolving field 63. In these conditions, if the apparatus is supplied by a source of alternating current, I may vary at will the direction and value of the current in the bulb, by a suitable choice of the value and phase of the tensions upon the coatings. For this reason, the latter disposition will be preferable to that of the converting devices in common use, from t-he fact that each electrode can be operated as a cathode or an anode as desired, and this will enable the use of a great variety of combinations of a valuable nature.

What I claim is:

l. The combination of an alternating current circuit, a load circuit, a continuously excited vapor electric device provided with a cathode and anode connected between said circuits and with an electrode arranged to control the current transmitted between said cathode and anode, and means arranged to vary t-he phase relation between the potentials of said electrode and said alternating current circuit.

2. The combination of an alternating current circuit, a load circuit, a continuously excited vapor electric device provided with a cathode and anode connected between said circuits and with an electrode arranged to control the current transmitted between said cathode and anode, and a phase control device connected between said cathode and said electrode.

3. The combination of a current supply circuit, a load circuit, a continuously excited vapor electric device provided with a cathode and an anode connected between said circuits and with an electrode arranged to control the current transmitted between said cathode and anode, means for applying an alternating potential to said electrode, and means interconnected with said electrode for varying the phase of said potential.

4. The method of controlling the transmission of power between different electrical circuits through a continuously excited vapor electric device provided with an electrode for controlling the transmission of current between its cathode and anode, which comprises varying the phase relation loe-y tween the potential of said electrode and the potential of one of said circuits to vary the magnitude of said power.

5. The combination of a trical circuits, a continuously excited vapor electric device connected between said cirs cuits, a control circuit for said device, and phase control meansconnected in said controlcircuit for varying the magnitude of the power transmitted between said circuits.

6. The method of controlling the voltage of a direct current circuit supplied with current through a vapor electric device provided with a cathode and an anode and with an electrode arranged to control the current transmitted between said cathode and anode, which comprises applying an alternating current potential to said control electrode, and varying the phase of said potential.

7. The method of controlling the relation between the electrical conditions of direct and alternating current circuits interconnected through a continuously excited vapor electric device provided with a cathode and an anode connected between said circuits and with a control electrode, which comprises energizing said control electrode at the same frequency as said alternating' current circuit, and varying the phase relation between the potentials of said electrode and, said alternating current Circuit,

plurality of elec- 8. In a rectifier containing al1-atmosphere of a. voltage applied to said anode, and of rareed gas or vapor, thecombination means whereby said voltage is utilized to of an anode and a constantly energized cath-` control the phase of the voltage of said con- 10 ode arranged to produce an aro through said trol electrode. atmosphere, an outer control electrode ar- In Witness whereof I have hereunto set ranged to prevent ignition of said are during my hand.

a predetermined fraction of the half cycle TOULON, PIERRE MARIE GABRIEL. l