US1597865A - Alternating-current system of distribution - Google Patents

Description

Aug. 31 1926.

G. E. PALMER ALTERNATING CURRENT SYSTEM 0'? DIST'HTBUTION M lynx! u u v A Sheets-Sheet 1 Original Filed July 6, 1920 IN l/E/V TOR G E PA L MU? Y WW A TTOR/VE Aug. 31, 1926.

G. E. PALMER ALTERNATING CURRENT SYSTEM OF DISTRIBUTION Original Filed July 6 1920 Patented 31, 1926 UNITED STATES PATENT OFFICE,

GRANVILLE E. ramanmor CAMBRIDGE, MASSACHUSETTS, 'ASSIGNQR, 'BY YMESNE Assmnmnnrs, TO wns'rmonousn anaem c & MANUFACTURING COMPANY, A 003- POIQATION OF PENNSYLVANIA J I I i I ALTERNATING- CURRENT SYSTEM OF DISTBJBU'I'IOIT.

Application fllcd July 6, 1920, Serial No. 394,116. Renewed March 12, 1926.

'My invention relates to improvements in alternating current systems of distribution and has for its object to provide a network system supplied by a plurality of step-down U transformers which derive theirprimary potentials from the same source or from separate sources and have their secondaries connected in multiple-to the network, which system as-a whole shall be reasonably proin which, when conditions are normal, the secondary connections wlll be restored auto-,

tected against damage and danger duev to short-circuit in a transformer primary supplying current to the network, and in which any supplying transformer can be, cut out and its primary and secondary supply mains, from its primary source and to the network respectively, interrupted upon the opening of a single switch on the primary side and matically upon the completion of the primary circuit.

In direct current circuits the use of a general network into which energy is fed from a plurality of stations has for many years been very general and the ability to feed this network from these several stations'has been of great importance, since one or more of the several sources can be cut oil at times of light load, such, for instance, as during the early morning hours, whereupon the other stations will supply the current needed. In the direct current systems shortcircuits are much less dangerous than in alternating current systems, .In fact in direct current systems it is customary to burn off troubles such as accidental short-circuits or grounds, the low voltage and high amperage making this a practical way of over-- -coming such difliculties; Not only is the cutting 'oflof any one of several direct -'current generating stations a comparatively simple matter, but the voltage at the switch produce death if a workman completes the circuit between opposite poles and it isnot practicable to burn off short circuits or grounds on the primary side because the highpotential might result in damage to a. v

great length of conducting cable as Well as tendlng to burn out the transformer conhaving a network fed by a plurality of transformers, a primary. is interrupted with-- out having the secondary disconnected, energy from the network flows in a reverse direction through the secondary winding not 00 necting the primary that is in trouble to the K network. Furthermore, when, in a system no satisfactory solution of the problem has I been made on account of thedifliculties hereinabove referred to and the complexity of the relations of transformers and the peculiarities of their action. ,v

The object of my invention, in addition to solving the :main problem hereinabove referred to, is further to provide forthe automatic interruption of any transformer secondaryfwhen its primary is interrupted, or short-circuited and further to provide means for automatically re-establishing the connectionsbetween the secondary and the network when conditions have become normaland the primary circuithas been completed. a

The following is a description of an embodiment of my invention, reference being had to the accompanying drawings in which Fig. 1 shows diagrammatically a systemembodying my invention, there being a distributing network 'supp'lled by two transformers each of which is independently controlled by means 'embodying my invention; Figs. 2, 3 and 4 show the details of a switch forming'part of my invention and particularly adapted for use in systems embodying it in all its particulars,

Fig. Qgbeing a front' elevation of the switch, while Fig. 3 is a side elevation of the same partly in section, the switch being in open position, and

Fig. 4 is a similar View, somewhat diagrammatic, showing the switch in closed position.

Referring more particularly to the drawings, 1 and 2 are distributing mains of a network which may be a two-wire system, or there may be a third main 3, as shown in the drawing, so as to form the well known threewire system. IVhere a three-wire system is used, this third main is usually grounded as at 4. 5 and 6 are secondary leads from the secondaries 7 of step-down transformers 8 in feeder circuits arranged in multiple to feed to the network. In accordance with well known practice in three-wire systems, these secondaries may be grounded at their central points 9. 10 are the primary coils of these transformers connected by primary leads 11, 12, respectively, to the high potential mains 13, 13, which may, if desired, be entirely separate from one anotherexccpt that they supply transformers connected to a common network. The primary leads are each provided with an overload circuit breaker, as shown at 14, which is actuated by the coils 15, in series with the respective primary coils, if the current becomestoo great, as for instance on account of a short-circuit, or can be actuated by hand. here the transformers are supplied by independent generators G, G in separate power houses, the circuit breakers 14 should be adjacent to the respective power houses.

In my present embodiment I provide as a means for opening and closing the secondary leads of each transformer, a main switch some of the features of which are described and claimed in Patent No. 1431,9436, issued to Ernest G. Johnson, Oct. 17, 1922, to which switch, however, I have added certain features which adapt it for use in the present embodiment. This main switch consists of terminals 112 and 113 and the co-operating movable laminated brush contact members 16, 17. The faces of the stationary contacts 112 and 113,- with which the portions 16 and 17 engage, are arranged at an angle of approximately 45, the ends of the members 16 and 17 likewise forming a right angle so as to make proper contact with said faces. The brush contacts 16 and 17 are secured to but are insulated from a crossbar 18 secured to an arm or lever 20 movable about a pivot or shaft 19. The movable switch members are moved into and out of-contacting relation with the station-' ary members 12 and 13 as the arm 20 is swung in one direction or the other a out its axis. The arm 20 is moved to closed position by a main solenoid magnet 24, the armature or plunger of which is pivoted to the arm 20 by a pin 26. The arm 20 is moved to open position by one or more springs 22 coiled about the shaft 19 and engaging with the arm or lever and a suitable abutment. The solenoid 24 is placed in a branch circuit, for which current is supplied from the transformer secondary, the circuit of which is between points a and b and through a certain relay and pallet switch hereafter referred to. For closing 'the branch circuits in the solenoid 24, soleplete magnetic circuit when an alternating current of predetermined potential is passed through the solenoid coils. Each of said members 28 and 29 has arm or plungers extending into the solenoid coils and which are brought into contact to form a complete magnetic circuit when the solenoid coils are excited by a current of desired potential. V hen such a current is passing through the solenoid, the two-part armature floats, the upper member 29 being free to rise, and produces no hum or chatter. The crossbar of the armature member 28 is provided with a lateral projection 30 upon which a movable contact member 31 (properly insulated therefrom) is mounted so as to make contact with and complete the electric circuit through two stationary spring contact members arranged in the branch circuit in which the main solenoid 24 is located. Assuming that the branch circuit of the solenoid 24 is otherwise closed, it will be understood that when the solenoids 27 are energized to cause the contact member 31 to be moved to active position, the main solcnoid 24 is energized to move the arm 20 from open to closed position, as shown in Fig. 4. thereby moving the main switch members 16 and 17 to close the main circuit through the stationary contacts 112 and 113. The stationary contacts 113 are connected to the terminals of the transformer secondary while the stationary contacts 112 are connected by suitable leads to the conductors 1 and 2 of the network.

In order to break the branch circuit through the solenoid 24 as soon as it has performed its switch closing function, a supplemental pallet or contact-or switch is employed. This mechanism comprises a contactor 33 adapted to be brought into electrical contact with two stationary contact members 34-34, which are respectively connected in series with the solenoid 24 so as to open and close the shunt circuit in which that solenoid is located. The mov able member, 33 is operated by an arm pivoted upon the shaft 19. This arm, which'is indicated at 35, is provided with a pivoted extension 37 hung thereto by a pin 36. -,A

'coil spring 38 is interposed'between'the exof the lever 35.

reach this position the tension and the arm so as to permit one to yield relatively to the other and to permit a certain flexibility of play of the contactor 33. A coil spring 39 between the lever 35 and shoulder on the arm tends to throw the arm and the contactor 33 downward so that the latter will engage. contacts 40. The arm 20, which is bifurcated on its lower end, is provided with a bridge or crossbar 41, one end of which is adapted to engage the lever 35 as the arm 20 moves from its closed position in Fig. 4 to its open position in Fig.3 and to swing said lever about its pivot so as to bring the member 33 into circuit closing position in engagement with the contacts 34. hen the said lever has reached this position,it is held there by a hook-latch 42. This latch is spring tensioned by a coil spring 43 to normally swing 'to the right in Figs. 3 and 4 so as to engage a finger 44 projecting from the pivoted end The hub of the latch 42 is pivoted upon a cross-shaft 45. The latch is so located in reference to the arm 20 that as the latter reaches its closed position'the crossbar 41 thereon will, exert a camming action on the latch 42 to swing it outwardly. and cause it to release the lever 35, whereupon the spring 39 will then force the lever 35 downwardly. The described construction and arrangement of parts are for the purpose of insuring that the contactor 33 is, when the main switch is open, in electrical contact with the contact members 34 of the branch circuit 24 and remains there until the lever 20 has almost reached its closed position, and so that as the arm 20 and the .promptly so as to-carry the conta ctor 33 away from the contacts 34, breaking the circuit through the solenoid 24, and by engaging the contacts 40 establish a portion of another circuit .to be hereinafter referred to.

As I have previously stated, the main switch members and the arm 20 are moved to closed position by the solenoid 24 acting upon the; plunger 25,and I have also explained that as soon as they approximately branch circuit through said solenoid is broken. To"hold the main switch members in their closed p0 sition, a lock is employed which is automatically operated by thesolenoid 24 or its equivalent to lock the lever 20 in closed,po-

sition and which is automatically released age.

when the current through the solenoids 27 fails or reaches a predetermined low volt- This locking mechanism comprises a bell-crank lever indicated. as a whole at 46 and having arms 47 and 48, as shown in Figs. 3 and 4. The arm 48 is formed of soft iron (laminated if desired), so as to constitute a second armature for the solenoid magnet 24. It extends downwardly across the end of the coil and is placed in a slot 49 in the plunger 25. The arm 47 projects across the upper end of the arm 20 and is bifurcated or yoke-shaped so as to form a fork between the arms of which there is a pin 50 and a roller 51. In the end of the arm 20 there is a. spring-pressed beveled dog 52 which, when the arm 20 is in closed position, is adapted to engage the roller 51 on the arm 47 and thus hold the arm 20 and the main'switch membersin closed position.

The bell-crank lever 46 is fulerume'd-upon a' pivot 53, which is so located that when the' moved and the arm 47 is swung down to its locking-position soas to engage the 'dog 52 and lock the arm 20 and the main switch members in their closed positions. It will thus be seen. that a mechanical l'ockis provided for the main switch which, by its mechanical action, 'holds the main switch closed but which is magnetically moved from its inactive or-non-operative position to its active or operative locking position just prior to the closing of the main switch. The lock is released upon failure of current through the solenoid 27 or when the potential falls below a certain value. To this end the bell- Erank' 46 has an arm 54 which projects to the right in Fig. 4 and which is adapted to be engaged by a member 55 depending from the armature 28 of the solenoids 27. This member 55 is 'shown in the form of a screw;

so that it may beadjusted longitudinally and" it is screwed into the projection 30.

The parts are so located that when the armature 28 is released by to solenoids 27, the member 55 in dropping will strike the arm 54 a hammer, blow and lift the locking bar 47 so as to release the dog 52 and permit the arm 20 to be moved to its open position, thereby opening the main switch members.

In my embodiment, I not only make use of the members 4040 as terminals of a branch circuit but upon the horizontal portion of the base of the switch provide circuit terminals 56 57, the former of which carries a contact-making plunger 58 retracted by a spring 59 and having an insulated head 60. The arm 20 is also provided with an extension 61, which, when the arm 20 is in open position, engages the head so as to force the plunger 58 into engagement with the contact 57, thus establishing a circuit between the terminals 56 57 for purposes hereinafter described.

In the present embodiment of my invention I also employ an'induction relay which is a well known type of apparatus used on alternating current circuits for controlling branch circuits under certain speciries with the solenoid coils 27. For my purposes I employ an induction relay in which the circuit between the terminals 205 is normally closed, this being accomplished by the use of a spring 206, a suitable stop being provided for limiting the movement of the contact 200. Contact brushes 205 are employed so as to produce a slowly opening relay;

for controlling the contacts 32-32, 34-34,

40-40 and 56-57, as above described, 'con-.

necting the main switch line terminals 113-113 with the load terminals of the secondary 7 and the load terminals 112112 with the mains 1 and 2 and interposing between each terminals 112-112 and its corresponding main a portion of the primary winding of a transformer, as shown at 207. The secondary is indicated at 208. This secondary is in series with the coils 204 of the induction relay and in this particular embodiment'with a coil 209 which constitutes the secondary coil of a transformer whose primary is indicated at 210. One end of the primary 210 is connected to the secondary leads at e and itsother end is connected through the conductor f to the same secondary lead between the primary winding 7 and the switch terminal 113 in the same lead. This other end of the primary 210 is also connected through a fuse g to oneof the contacts 34. Contacts 40v and 56 are directly connected to one another and are in series with the shunt coil 203 of the induction relaywhile the other contact 40 is connected to the left-hand secondary lead;

between the contact 112 and the main 1;? The contact 56 is connected through the fuse;

in the reverse direction to normal.

In embodying my invention in the presentform I use the main switch, having means 9 with the point I) and also through the coil 210 with the point e. The electromotive .forces produced in the circuit of the coil 204 by'the action of the coils 207 and 208 and the coils 209 and 210 and the currents resulting therefrom are such that the currents in flowing through the coils 204will, in conjunction with the current in the coil 203, produce a torque in the disk 201 which will overcome the spring 206 when energy flows in the reverse direction from the network to the secondary coil 7.

When the system is in normal operation the parts are in the position indicated on the left-hand side of Fig. 1, the circuit breaker 14 being closed, the path between the contacts 3232 being closed by the contact 31 for the reason that the circuit through the coils 2727 is closed by reason of the engagement of the contact 200 of the induction relay with the brushes 205, the path between the contacts 3434 being open, the path between the contacts 40-40 being closed and the path between the contacts 56 and 57 I being open.

When conditions are normal, the secondary 7 will be supplying energy to the line. If, however, the circuit breaker 14 should be opened the secondary 7 will thereupon receive energy from the network, which energy will flow through the secondary leads This reverse energy passing through the trans formers primaries 207207 will introduce reverse energy in the secondary 208, which will reverse the direction of the rotating field produced by the coils 203 and 204 and therefore reverse the rotation -of-the induction meter, causing the disk 201 to turn clockwise against the action of the spring 206 so as to withdraw the contact 200 from the brushes 205. This will open the circuit through the solenoid coils 27, permitting the armature 28 to drop so as to cause the member 55in falling to strike the projection 54 and cause the arm 47 to release the detent 52 on the arm 20, opening the circuit through the secondary leads. The opening of the circuit breaker 14 thus results in disconnecting the primary winding from the source and the secondary winding from the network.

' The primary 210 is in shunt across the terminals 112-113'in the same secondary lead so that when the main switch is open reverse energy, continues 'to flow through the primary 210 on account of the grounds 4 and 9. This coil 210 is so wound that it too induces reverse current in its secondary 209' so that reverse energy continues to flow through-the relay coils 204 even after the main switch is opened so as to interrupt most of the current through the coils 207. A reverse torque upon the disk 201 is therefore maintained andthe contact 200 is kept spring 206.

If now,

on the terminals 112 will become the same as potential on the" terminals 113 and no current will flow through the primary coil 210, with the result that the torque in the induction relay will fail and the spring 206 will cause the contact 200 to engage the contact brushes .205 and thus re-establish the circuit through the solenoid coils 27, which will result in the liftin of the armature 28, the closing of the clrcuit between the contacts 32 and the re-establishment of the circuit through the solenoid 24, the contacs tor 33 havin upon the opening of the switch moved away from the contacts 4040 into-engagement with the contacts 34- -34, as shown in theright-hand portion of Fig. 1, and the contact 58, by connecting the contacts 56 and 57 upon the o ening of the main switch, having re-establis ed a cir-f cuit through the shunt coil 203, which was. broken by the movement of the contactor 33 away from thecontacts 40.

Inna somewhat similar manner, if the primary or the secondary of the transformer 8 should be short-circuited, so as to cause reverse energy to flow through the coils 207-207, the induction relay would operate to disconnect the brushes 205 so as' to deenergize the solenoid coils 2727 andopen It will be further seen that this invention whenever the. primary is fuses.

the transformer is comparatively simple,

the main switch. This would disconnect the transformer secondaries from the network, whereupon .the main switch 'would be maintained in open, position until normal conditions were restored, and thereupon be automatically closed upon the closing or the primary so as to again place the transformer in circuit with the network.

From the foregoing it will be seen that by means of this invention any supply transformer, by the opening of asingle switch in its primary can be entirely disconnected from its source and also from a secondary network, and that 'upon the closing of a single switch in its primary the original connections with the source and with the 1 network will be automatically re-estab-vv mary, so as todo away with any losses due to magnetizing currents in the transformers during the intervals of non-use.

by means of short-circuited the secondary is automatically disconnected from the network so as to prevent thenetwork from feeding backward into the transformer and producing a dangerous otential upon the primary termlnals whi e the short-circuit is being re things being otherwise normal, the circuit breaker 14 is closed the potential" paired, and that after the short-circuit is: repaired the closing of the primary circuit will'automatically result inthe re-establishment of the connections between the second: ary and the network. 7 I

It is further to be noted'that inasmuch as the circuit through thesolenoids 2727 is a normall closed circuit the system is self-superviseh so that if the circuit controllin the magnet, whose action is de pende upon to open the main switch, is for any reason broken or out of order that fact would become immediately evident b the (penin of such main switch, whic woul not he the case if the circuit of the controlling magnet were normally open.

The use or a'coil 207 in each of the leads connected to the mains 1 and 2 of the threewire system is important since, if either ofthe leads should be interrupted, a reversal in the other lead will actuate the induction relay; When a. transformer is disconnected from its-source it 'is always disconnected from J the net work, When it is ready to be re- 90 connected, the parts are in the position 'shown' in the right-hand portion of Fig. 1,

the contacts 3434 being bridged and the and; therefore no reverse energy flows through the series coils 204' of the induci tion relay, The spring 206 thereupon causes the contact 200 to move and engage the brushes 205 so asto'close the circuit through, the solenoids 27. This acts to cause the contact 31 to bridge thecontacts 32, which closes the circuit through the solenoid 24, which acts to throw the arm 20 so as to cause the members 16 and 17 to engage the contacts 112 and 113 and close-the secondary circuit. This immediately shunts the, coil 210 so that current no longer flows therethrough, but current flows through the coils 207 introducing current in the coil 208 in '11. a normal direction, which acts in conjunction with the spring 206 to maintain the contact 200 in closedpo'sition.

The most important feature of my in- I vention consists in its automatically looking 1!. out for short-circuit conditions which con-- ditions in direct current network systems sity of special apparatus to control the -al-' feed from other sources, would be possibly equal to or greater than the high primary potential, none of which conditions are present in direct current systems. The n'e-v cessity of special apparatus also results from the difficulty of throwing into circuit an alternating current generating source which has been disconnected, since if the current from the incoming source is not -.of the proper potential or properly in phase with the current of the net work, when switches are thrown to connect a transformer in circuit there is great danger of serious accident. V'Vith my system, however, on account of the automatic action of the means for closing the secondary leads, the secondary will not be connected to the network if the primary is not properly in phase or the primary potential too low. My invention therefore guards against the cutting in of a transformer if either the phase or the potential are not such as to make such action safe.

As the main switch opens the flow of energy through the series transformer coil 207 is interrupted but a new circuit is established through a path 7 across the open switch blade through the primary'21O of a phasing transformer, which supplies its energy to its secondary 209 and to the lower element 20 1 of the relay to hold the relay contact 200 in open position, the upper element of the relay 203 also obtaining its potentia-l, being energized by the difference of I primary, sufiicient potential existing across the open switch between one pair of terminals 112, 113, the connections to the potential coil having been changed from a multiple connection across ,the leads connected to the network by the opening of the path between the contacts 40 and the closingof the path between the contacts 5657. The contacts 40-40 are disconnected before the contacts 5657 are closed by the plunger 58. When the primary is s ort-cirouited orthe current fails in the potential will be present across the open switch to energize the coils of the induction relay, as above described, so as to keep its contact open, the current flowing through the "conductor 7 through half of the winding of the secondary 7 of the main transformer to ground, and through the ground to the neutral of the network,

The 00115 210 and 203 are of such small capacity that the current passing through them and the coil 7 produces no substantial potentials at the terminals of the" primary 8 when the switches 14 and 16', 17 are open.

When the'primary and secondary windings are insulated from one another, the secondary of the auxiliary transformer preferably is in series with the other secondary so that the current induced in the coil 209 flows in series through the secondary 208,

making it unnecessary to provide means for cutting out the secondary 209 under normal conditions, as would be the case if the secondaries'208 and 209 were in parallel.

As will be evident to those skilled in the art, my invention permits of various modifications without departing from the spirit thereof or the scope of the appended claims.

WhatI claim is 1. In an alternating current system of dis tribution, the combination of a network of conductors, a plurality of transformers normally supplying energy thereto in multiple, a circuit breaker in the secondary leads of each transformer respectively, each of said circuit breakers when closed normally tending to move to open position, a controlling 0011 for each circuit breaker, means controlled by said coil for controlling the movements of its circuit breaker so that it opens when said coil is de-energized and closes when said coil is'energized, and a relay for each circuit breaker connected to the system and acting to de-energize said coil so as to open its circuit breaker when the energy in the corresponding transformer feeders reverses and to energize said coil 50 as to close its circuit breaker when the potential and phase relations across 'the open terminals of its circuit breaker become approximately 1 normal.

2. In an alternating current system of distribution, the combination of a network of conductors, a plurality of step-down trans formers supplying energy thereto in multiple, a circuit-breaker in the secondary leads of each of said transformers, each of said circuit breakers when closed normally tending to move to open position, and having a solenoid which when energized closes said circuit breaker and a second solenoid which when energized closes the circuit through said closing solenoid when the circuit breaker is open and when de-energized trips said circuit breaker so that it opens, and means connected to said leads and electrically con-'. trolled therefrom for de-energizing sald sec- 0nd solenoid when the energy in said leads is .reversed and energizing it when potential conditions are normal.

3. In an alternating current system'of distribution, the combination of a network .of conductors, a plurality of step-down transformers supplying energy thereto. in multiple, a circuit breaker in each of the secondary leads of said transformers, each of said circuit breakers normally tending to move to open position and having a solenoid which w enenergized closes said circuit breaker and a second solenoid which when energized closes the circuit throu h said closing solenoid when the circuit reaker is open and when de-energized trips said circuit breaker so that it opens, and means connected to said leads and electrically controlled therefrom for de-energizing said second solenoid when the direction of energy in said leads is reversed with respect to normal and maintaining said second solenoid de-energized when the circuit breaker is open and a substantial difference in otential exists across the disconnected terminals thereof and for energizing said soenoid when potential con ditions are normal.

4. In an alternating current systemoi distribution, the combination of a network of conductors, a plurality of step-down transformers supplying energy thereto in multiple, a circuit breaker in each of the, secondar leads of said transformers, a solenoid embo ying means that when said solenoid is energizedv effect the closing and when deenergizedthe opening of said curcuit break er, .an induction relay normally tending to close the circuit through said so'enoid, and

meanscontrolled by said circuit breaker for producing 1n said induction relay a closing torque where the conditions are normal and an opening torque when the energy in the secj ondary leads is reversed with respect to-normal, holding saidinduction relay open when I the contacts of said circuit breaker'is open and a substantial diflerence of potential exists between the breaker that are connected together when the breaker is closed and perm tting said induction relay to close when the potential conditions of the line and load terminals of said circuit breaker are substantially equal. I l

5. In an alternating current system of distribution,,the combination of a network of conductors, a plurality of step-downtrans- T formers supplying ener thereto in mul ti-ple, a circuit breaker in each of the secondary leads of. said transformers, said circuit-breaker 'normally tendin v to move to fo'pen positlon, a solenold whic when enersaid circuit V reaker is open, an indu'ction gized closes said circuit breaker, a second solenoid which when energizedcloses the circuit throu h said closing solenoid -when relay normally tending to close the circuit throu h said second solenoid, and means con-.-

trolle by said circuit breaker for produc- "ing in said induction relay a closing torque when the potential -cond1tions" are normal and an opening torque when the energy in the secondary leads is reversed withrespect to normal.

6. In an alternating current system'of dis tributiom the combination ota' network of conductors, a plurality of step-down transformers supplying energy ,ther'eto i'n 'mul tiple, a circuit breaker in each of the secondary leads of said transformers, said cir- .cuit breaker normally tending to move to open position, a solenoid which when energized closes said circuit breaker, asecond solenoid which when energized closes the circuit through said closing solenoid when said circuit breaker is open, an induction relay normally tending to close the circuit through said second solenoid, and means controlled by said circuit breaker for produc ing in said induction relay a closing torque when the potential conditions are normal and an opening torque when the energy in the secondary leads is reversed with respect.

to normal, and holding said induction relay open when said circuit breaker is' open and the potential at the terminals of the secondary is substantially different from the potential at the terminals connected to the net Work. A

7; In an alternating current system of distribution, the combination of a network of conductors, a plurality of step-down transformers supplying energy thereto in multi'le, acircuit breaker in each of the cuit through said second solenoid, and means controlled by said circuit breaker for producing in said induction relay a closing torque when the'c'onditions are normal and an opening torque when the energy in the secondary leads is reversed, holding said induction relay open when said circuit breaker is open and a substantial difference of potential exists between'the contacts of the breaker that are connected together when the breaker is closed, and permitting said llO induction relay to, close when a said circuit breakeris open and the potential conditions at its terminals-are substantially equal.

conductors, a plurality of step-down transformers supplying energy thereto in multiple a circuit breaker in ,each'of thelsecondleads of, said transformer, said circuit :8. In an alternating current system of dis tribution, the combination of a network ofbreaker normally tending to move to open position, a solenoid which when energized closes-said circuit breaker, a second. sqlenoid which when energlzed closes" the circult through,said-closingsolenoid, when said circuit breaker isopen. an induction relay norvmally tending to close-the circuit through said'second solenoid, means controlled by said circuit breaker for producing in .said

induction relay 9, closing torque when the conditions are normal and an opening torque when the energy in the secondary leads is reversed, holding said induction relay open when said circuit breaker is open and the potential at the terminals of the secondary is substantially different from the potential at the terminals connected to the network, and permitting said induction relay to close when said circuit breaker is open and the potential conditions at its terminals are substantially equal, means for opening the circuit through the closing solenoid when said circuit breaker is closed, and meansfor mechanically holding said circuit breaker closed, said means being released by the armature of said second solenoid when deenergized.

9. In an alternating current system of distribution having a network and a plurality of transformers connected to the same in multiple through independent feeders and normally supplying energ 7 thereto, the combination of a plurality of elec tro-magnetically controlled circuit breakers in said feeders respectively between each of said transformers and said network, each circuit breaker comprising an electromagnetic device and means controlled thereby acting to open said'circuit breaker when its said electro-magnetic device is de-energized and to close the same when said electro-magnetic device is energized, with means associated with each electro-magnetic device respectlvely and responsive to a reverse of normal energy fiow for automatically de-energizing said .electro-magnetic device when the energy flow of said corresponding transformer is reversed from normal, and responsive to the dliference of potential between correspondng terminals of its circuit breaker when said circuit breaker is open to automatically energize said electro-magnetic device when conditions are such that no reverse energy would be supplied to said feeder from the network if said circuit breaker were closed.

10. In an alternating current system of distribution, the combination of a network of conductors adapted to distribute energy to a connected load, a plurality of transformers, means for supplying alternating current to their primaries, a plurality of feeder circuits connecting said transformers to said conductors in multiple, a circuit breaker in each feeder circuit comprising an electromagnetic closing device acting, when energized, to close said circuit breaker, and a second electro-magnetic device acting, when energized, to energize said closing electromagnetic device' and, when de-energized, to open said circuit breaker, and a relay responsive to a reversal of the normal energy flow in said feeder circuit to de-energize said second electric-magnetic device, and responslve to potential and hase conditions between open terminals of said circuit breaker of feeder circuits arranged in multiple for feeding energy to said working .circuit, a transformer in each feeder circuit, a switch in the primary circuit of each transformer, and means in the secondary circuit of each transformer acting automatically, when said secondary circuit is open, to close said secondary circuit when the working circuit is energized, only when the switch in its transformer primary circuit is closed, the potentials in said secondary and said working circuit are substantially in phase, and the potential of said secondary circuit is at least substantially as high as that of said working circuit.

12. In an alternating current system of distribution, a working circuit, a plurality of feeder circuits arranged in multiple for feeding energy to said working circuit, a transformer in each feeder circuit, a switch in the primary circuit of each transformer, and means in the secondary circuit of each transformer acting automatically, when said secondary circuit is open, to close said secondary circuit when the working circuit is energized, only when the switch in :its transformer primary circuit is closed, the potentials in said secondary and said working circuit are substantially in phase, and the potential of said secondary circuit is at least substantially as high as that of said working circuit, and acting to open said secondary circuit when the potential or phase relations or both between said feeder circuit and working circuit are such as to permit energy flow from said working to said feeder circuit, with said secondary circuit closed.

13. In an alternating current system of distribution, a working circuit, a plurality offeeder circuits arranged to feed energy in multiple to said working circuit, a main switch in each feeder circuit, a circuit break or controlling each feeder circuit, and mechanism in each feeder circuit for automatically closing the corresponding main switch, when open, when its circuit breaker is closed, the phase conditions in the feeder and working circuits are substantially similar, and the potential of said feeder circuit is at least substantially as high as that of said working circuit, and for opening said main switch when said circuitbrcaker is open or when energy flows in the reverse direction from said working circuit to sald feeder circuit.

14. In'an alternating current system of distribution, a working circuit, a plurality of feeder circuits arranged in multiple for feeding energy to said working circuit, a switch in each feeder circuit, and mechanism interlocked with the switch and subjected to potential across the line and load terminals of each switch acting automatically, when said switch is open, to close said switch only when the potential of said line terminal is at least substantiallyas high as that of said load terminal.

15. In an alternating current system of distribution, a working circuit, a plurality of feeder circuits arranged in multiple for feeding energy to said working circuit, a switch in each feeder circuit, and mechanism subjected to potential across the line and load terminals of each switch acting automatically, when said switch is open, to close said switch only when the potential at said line terminal isat least substantially as highas that of the load terminal of the open switch, and responsive to direction of energy flow between the workin circuit and feeder, to open said switch on 50w from said working circuit to said feeder.

16. In an alternating-current system of distribution, a working circuit, a feeder circuit, for supplying energy to said working circuit, a switch for said feeder circuit, con-' trolling means for said switch comprising a voltage failure releasing mechanism and electro-r'esponsive means for controlling said releasing mechanism under conditions of energy reversal in saidswitch andfor preventing the're-energization of the releasing mechanism while an undesirable phase relationship or voltage, difference exists between the working circuit and the feeder circuit. a a v 17. In an alternating-current system ofdistribution, means for supplying alternating current, a working circuit, a plurality of feeder controlled thereby are such'that said feeder circuits arranged in multiple to feed from said supply means to said working circuit, a switch for controlling each feeder circuit, and means acting to close and maintain closed each of said switches only when the potential and phase conditions of the feeder may feed energy to said working circuit. I

18. In an alternating-current system of distribution, a working circuit,"a plurality offeecler circuits for supplying energy to said working circuit-,a transformer in each feeder circuit adjacent said working circuit, a switch in each feeder circuit adjacent each transformerand means for always closing said switches when the conditions in'the feeder circuit controlled thereby are such that energy will not flow in the reverse direction from the working circuit to the feeder circuit after the switch is closed.

19. In an alternating' current system of distribution, aworking circuit,aplurality of feeder circuits for supplying energy ,to said working circuit, a'transformer in each feeder circuit adjacent said working circuit, a 6! switch 1n each feeder circuit adjacent each switches when the conditions in the feeder circuit controlled thereby are such that energy will not flow in the reverse direction from the working circuit to the feeder circuit after the switch is closed.

20. In an alternating-current system of distributing, a working circuit, a plurality of feeder circuits arranged in multiple for feeding energy to said working circuit, an automatic switch in each feeder circuit, an electro-respons ive device comprising a pluralityvof cooperating coils for controlling each switch and means for altering the relations of said coils to the circuit when the switch operates to permit the electro-responsive device to control both the opening and the reclosure of said switch, said coils being so arranged that the device ope-ratesin accordance with the, direction of the flow of energy in the feeder circuit when the switch is closed and in accordance with the relative potentials of the feeder and working circuit when the switch is open.

distribution, a working circuit, a plurality of feeder circuits in parallel for supplying energy to said working circuit, a switch in each feeder circuit adjacent said working circuit and means operative to close each of said switches when the associated feedercircuit is energized irrespective of the ener-' gized or de-energized condition of the workmg circuit. 1

22. In an alternatm -current system of distribution, 'a working circuit, a plurality ergy flow therethrough and for-reclosing the same when the working circuit is de-energized or energized to a potential not greaterthan that of-the feeder circuit.

23. The combination with a transformer having a high-Voltage supply circuit and a low-voltage secondary circuit connected thereto, of a switchin each of said circuits,

means for operating both of said switches upon the occurrence of a fault in the suply circuit or transformer and means where y the switch in the-secondary circuit is au-,

' tomatically reclosed upon the-energization of said supply circuit to a predetermined degree. 1 v

24. The combination with an alternatingcurrent supply circuit and a load circuit connected thereto, of a '"switch between said circuits, means for opening the switch upon the occurrence of a fault and synchronizing means for reclosing the switch upon the occurrence of substantially equal in-phase potentials on opposite sides thereof.

25. In alternating-current system of distribution, means for supplying alternating current, a working circuit, a switch between the supply means and the working circuit and means acting to close and maintain closed said switch only when the electrical conditions of the system are such that the of feeder circuits arranged in multiple to feed from said supply means to said working circuit, a plurality of switches controlling the flow of energy in said feeder circuits, means for opening and closing each switch and means dependent upon the direction of the flow of energy through the switch for controlling said opening means when the switch is closed and dependent upon the relative potentials of the feeder and working circuits for controlling the closing means when the switch is 0 en. a

28. In an alternatlng-current system of distribution, a source of current, a load circuit, a switch between said source and said load circuit, an electroresponsive device comprising a plurality of coils for controlling said switch "and means associated with the switch whereby one of said coils is energized in accordance with a function of the current traversing the switch when closed and in accordance with a function of the potential across the switch when open.

29. The combination with a switch and a constantly-energized controlling device therefor, of means dependent upon the position of the switch for so altering the cnergi zation of the controlling device that the switch is opened by the controlling device upon the occurrence of predetermined ahnormal circuit conditions and is reclosed by the controlling device when normal conditions obtain.

30. The combination with a switch and a controlling device therefor, of a contact device associated with the switch to be operated when the switch operates and disposed in the circuit of the controlling device and means including the contact device for rendering the controlling device operative to open the switch upon the occurrence of predetermined abnormal circuit conditions and to close the switch when normal conditions obtain.

GRANVILLE E. PALMER.

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