US1560284A - Pole-changer switching circuit - Google Patents

Description

Nov. 3,1925- J. F. MEYERS POLE CHANGER SWITCHING CIRCUIT Filed- Oct. 1. 192;

ME? I Patented Nov. 3, 1925.

UNITED STATES PATENT OFFICE.

JOHN F. MEYERS, OF CHICAGO, ILLINOIS, ASSIGNOR TO KELLOGG SWITCHBOARD AND SUPPLY COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

POLE-CHANGER SWITCHING CIRCUIT.

Application filed October 1, 1923. Serial No. 685,798.

To ("N 1071071), if may concern.

Be it known that I, Jenn F. Mnrnns, a citizen of the United States of America, residing in Chicago, county of Cook, and State of Illinois, have invented certain new and useful Improvements in Pole-Changer Switching Circuits, of which the following is a specification.

My invention relates to switching circuits and has to do more particularly with circuits in which duplicate sets of apparatus are employed and in which means are provided for automatically switching from one set of apparatus to another. In telephone systems of the class in which pole changers are used for delivering ringing current, duplicate pole clnlnger sets are employed, one of which may be termed the primary pole changer and the other pole changer may be termed the emergency pole changer. It sometimes happens that the primary pole changer becomes disabled and stops for various reasons such as mechanical trouble, or circuit trouble thus making it necessary to employ the emergency pole changer. In order to connect this emergency changer, the operator presses a button which is located on the switchboard and under her control, or a switch which is located on the powerboard. This means of connecting and disconnecting the pole changers is objectional because of loss of time and the interruption of ringing current, it being done manually. To overcome'these objectional features, I provide a switching cir-.

cuit which automatically switches from one pole changer to the other.

A. feature of my invention is the provision of a key which when moved to one position, places the primary pole changer in operative circuit and when moved to its other position the primary pole changer is cut off and places the emergency pole changer in operative circuit so that the primary pole changer may be used for a period of time and when desirable this primary pole changer may be shut oil by opening its associated key contacts, and the moving of the key to its other position will connect the emergency pole changer in operative circuit for any desired length of time. I

Another feature of my invention is the provision of means whereby should the primary pole changer which is #onnccted in pole circuit by means of its associated key contacts stop for various reasons, such as the opening of a fuse, or mechanical trouble, the said means -will function automatically to switch from the primary pole changer to the emergency pole changer without the manipulation of any keys 'or buttons.

Another feature of my invention is the provision of one set of transformers for the primary and emergency pole changers and automatic means which control the switching of the transformers from one pole changer to the other when the switching means operates to switch from one pole changer to the other.

Referring now in general to my invention as illustrated in the accompanying drawing, 1 shown a primary pole changer A comprising units M and N. The units 'M and N comprise vibrator magnets Vhl and VM and their associated vibrator contacts. The pole changer C which I term the emergency pole changer comprises the units 0 and P which consist of the vibrator magnets VM and VM and their associated vibrator contacts. I show a transformer T which is common to the units M and O of the pole changers A and C and a transformer T which is common to the units N and P of the pole changers A and C. Retardation coils RC and RC .are also provided, retardation coil RC being common to units M and O of the pole changers A and G and retardation coil RC being common to units N and P of pole changers A and C. The retardation coils are used for the usual tone purposes. I also provide a pole changer switching relay PR which is associated with the units M and O of the pole changers A and C and when operated switches the transformer T from the unit M of the pole changer A to the unit O of the pole changer C and also switches the retardation coil RC from unit M to unit 0. A pole changer switching relay PR" accociated with the units N and P of the pole changers A and C when operated switches the transformer T from the unit N of pole changer A to unit P of the pole changer C. I also show alternating current relays AC and AC, the relay AC being common to units H and O of pole changers A and C and relay AC'heing common to units N and P of the pole changers A and C. An emergency control relay ECP is provided and in association with the relays AC and AC the said relays automatically control the switching from the pole changer A to C or vice versa. 7

I provide a switching key K which is of the usual cam type, and has two positions a. and 0. lVhen the key is moved to its a position the pole changer A is the pole changer that will be operated when the starting key SK is moved to its starting position SP and when the key K is moved to its position the pole changer C will be the pole changer that is operated when the starting key is moved to its starting position SP. The starting key SK is also of the usual cam type and has a starting position SP and an emergency position EP to which it is moved from its starting position SP when starting the pole changer A or G as the case may be for purposes as will be more fully hereinafter described. I provide a battery switching key BK of the usual cam type to connect either the batter B or B for current supply purposes.

I also provide a testing key 'TK associated with the pole changer A for testing the pole changer A and a testing key TX for testing the pole changer C.

Having described in general the apparatus comprising my invention, I will now describe in detail'the operation of the switching circuit of my invention.

Assuming that the primary pole changer A is the pole changer being used, its associated key switch K is moved to its position (L and further assuming that the battery B is being-used, its associated battery switch ing key BK will be in its actuated position. To startthe pole changer A, starting key switch SK is moved to its. starting position SP to close a circuit for the vibrator inagnets VM and VM of. the units Mfa'nd N of the pole changer A, the circuit of vibrator magnet VM- being traced from battery B, over conductor 2, closed contacts 3 an (1 4. of the battery key BK,'conducto'rs 5 and 6, the fuse 7, conductor 8 through the winding of the vibrator magnet VM, its interrupter contact 9, conductorslO and 11, closed contact 12 of the key switch aassociated with the pole changer A, conductor 13, closed contact 14c of the key switch SK, conductor 15 to the other side of the battery B. The

circuit for vibrator magnet VM of the unit *ll of pole changer A may be traced from battery'B over the path just described to the branch over conductor 16, through the winding of the magnet VM, its interrupter contact 17, armature 71 conductor 11 to the other side of the battery B over the previous described path.

The vibrator magnets W 13i and VM 0t nnits'l i and N of the pole changer A are energized over the circuits just described and due to their interrupter contacts 9 and 17 the armaturcs 70 and 71 of the said nagconductor 2 closed contacts 5 3' nets VM and VM are vibrated. The alternate closing of vibratory contacts and 51 of the vibrator magnet VM P81111113 impulses of current to flow through the windings 18 and 53 of the primary P of the transformer T, the circuit through the winding 18 of the transformer 1 being traced from battery B over conductor 2, closed contacts 3 and at 01 the battery switching key BK, conductor 5 to the point 1:), and extending from the point 19 over conductor :20, ftuse :21, winding 18 ot the primary- P of the transformer T, conductor 22, contact 23 off the pole changer switching relay PR, conductor 21, closed contact and armature 7 0 of the vibrator magnet Viii -iondu'ctors and 11, closed contact 12 of the switching key K, conductor 13 and closed contact 1% of the starting key SK, coiuluctor to the other side of battery.

The circuit through the wii'niing 53 of the primary P of the transior 'l when contact 51 is closed may be that and L of battery switching key Bil, conductors and 20,-tuse 21, winding 53, conductor 54, normal contact 55 of relay PR, conductor as, closed contact 51 and aruu-itnrt of magnet VM, conductors 10 and 11 to the other side of battery 13 over the path described in connection with the circuit of wind ng 18. The impulses of current through the winding: 8 and 53 of the primary P 01" the transformer T which are induced into the secondary winding 32 of the secondary S of the transformer T pass over conductors and 101 to conductors 33 and 3 1, through the wind-- ing of the alternating current relay AC, associated with the transformer T. The re tardation coil RC is provided for tone purposes and has its primary winding 102 out acro'ssthe armature 70 and contact?) of the vibrator magnet VM thus placing it in parallel connection with the sa-id magnet- VM. One terminal of the primary 102 is connected over conductor 103 through normal contact 104 of relay PR, conductor 105 to the armature 70 which is connected to one side of battery The other side of the primary 102 is connect-ed to the other side of battery B at contact 9 so that when magnet VM vibrates the opening and closing of contact 9 and armature 70 will cause surges of current to flow through the primary 102 which are induced into the secondary winding 106 which produce a tone which is delivered over conductors 107 and 108 to the swiftcl'ibo'ard with which pole changer A is associated, the tone being used for various purposes as is known in the art.

The vibrator magnet VM of the unit N 01" the pole changer A is vibrated by reason of its energizing circuit just described and the alternate closing of its vibratory'contacts :32 and 31 permits impulses of current Lil) to flow through the windings 1S and 53 of the primary l. of the transt'ormer T. The circuit through winding 18 being traced from battery B to the point 19 and over conductor 26, i'use 2T, winding 18, conductor 28, normal contact 29 of relay PR conductor 30, closed contact 31 and armature 71 ot' the vibrator magnet TM, conductor 11 to the other side of battery 13 over the path traced in connection with winding 18 t transformer T. The circuit through the winding 55 ot the primary P of transformer T of the unit N of pole changer A when contact is closed is traced from battery I to the point 19 and over conductor 26, fuse 2T winding 53, conductor 57. normal contact 59 of relay PR condu. tor 58. closed contact and armature T1 of magnet Ysl, conductor 11 to the other side oi battery B. The impulses of current through the windings 18 and 53 ot the primary P of the trans former T are induced into the secondary winding 32 ot the secondary S of the transformer T and pass over conductors (30 and 61 to conductors and 136, through the winding of alternating current relay AC associated with the transformer T. The retardation coil RC associated with the pole changer unit I? has its primary 102 also connected in parallel with the magnet YM across armature (land cont-mt 1T operates in a manner similar to BC to deliver a tone to the switchboard over conductors 110 and 111. Current over conductors 35 and 36 also passes through the alternating current relay AC associated with the unit N of the pole changer A.

The startin key switch SK is of the well known cam key type and when moved to its starting position SP to start the operation of the pole changer A, it is immediately moved to the right into its emergency position EP to close the spring contacts 2-37 and 38 for purposes as will presently be described.

Relays AC and AC upon energizing close their alternate contacts 39 and 10 to establish an energizing circuit for the emergency control relay EUR traced from battery B, conductor 2, closed contacts 3 and l of the battery switching key BK, conductors 5 and a1 through the winding of the relay ECR conductor 12, alternate contact 39 of the alternating current relay AC, conductor alternate contact it) of the alternating current relay AC, conductors H and 15 to the other side of battery. The initial energizing circuits or" the vibrator magnet VM and VM of the pole changer A were opened when starting key SK was moved from its starting position SP to its emergency position EP but a substitute circuit is now established tor the vibrator magnets VM and VM, the circuit of magnet VM being traced from battery B, conductor 2, closed contacts and 1 or the battery key BK, conductors and (3, fuse T, conductor 8, through the winding or the magnet YM, its interrupter contact 9, conductors 10 and 11, closed contact 12 ot the key switch (4, associated with the pole changer A, ctmductor 15, normal contact t6 of the switching relay STY, conductor 1T, alternate contact 1 8 of the relay EUR, conductors 19, 50, it and 15 to the other side of battery B. The circuit for the vibrator magnet VM oi the pole changer (6 extends over conductor 16 through the winding of the magnet VM, normal contact 1T, conductor 11 to the other side of battery 13 over the path just described in connection with the vibrator magnet VM. The windings 18, and 1S of the primary windings 1" and P of the transtormers T and T receive current from battery B over condu' tors 20 and 243 normal contacts and 55 of relay PE and normal contacts 29 and 59 of relays PR, conductors and 5t, 28 and 57, cont-acts and 51 of magnet VM, contacts 31 and 52 of magnet V11, conductor 11 to the other side ofbatt-ery 13 over the return path just traced in connection with the magnets VM and VM.

The current from the winding 32 of the secondary S of the transformer T passes over conductors 100 and 101 to conductors and 34. which lead to the switchboard with which the pole changer A is associated. The current passing over conductors 3B and 3-:l delivers a pre-determined cycle of ringing current to the switchboard. This current also flows through the alternating current AC and holds said relay energized as long as the unit X of the pole changer A is operated. The current from the winding 32 of the se-ondary S of the transformer T which passes over conductors 6t) and (31 to the conductors 35 and 36 which conductors lead to the switchboard with which the pole changer A is associated to deliver a predetermined cycle of ringing current thereto. The current also passes through the wind mg of the alternate current relay AC. associated with the unit N of the pole changer A and said relay AC remaining energized as long as the unit N is operated.

Assuming that the primary pole changer A fails in its operation for the reason that the fuse 7 opens the vibrator magnets VM and VM of the pole changer, units M and N will receive no battery current from the battery B. The vibrator magnets VM and VM of units M and N of the pole changer A remain inert and the armatures and T1 of the vibrator magnets VM and VM come to rest and the contacts 25 and 51 of the magnet VM, contacts 31 and 52 of the magnet VM are open. The windings 18 and 53 of the primary P of the transformer T and windings 18 and 53 01 the primary P of the transformer T receive no current and therefore the alternating current relays AC and AC de-energize and restore to normal. The opening-of alternate contacts 39 and LO of the relays AC and AC open the energizing circuit of the relay ECR and the said relay EOE upon de-energization permits its normal contact i8 to close to establish an energizing circuit for the switching relay SW, traced from battery 13, conductor 2, closed contacts and t of the battery BK, conductor 5, conductor 41 through the winding of the relay SW, conductor 72, closed contacts 37 and 38 of the starting key SK will be remembered that the starting key SK was moved to its emergency position to close thecontacts 37 and 38 conductor 73-, normal contact 4-8 of the relay EGR. conductors 19, 50, 44: and 15 to the other side of battery B). The switchingrelay SlV upon ener-giz'ation, establishes a locking circuit for itself traced from battery B, conductor 2,-closed contacts 3 and 4 of the key BK, conductors and 41 through the windingof the relay SW, conductor 72, closed contacts 37 and 38 of the key SK, conductor 73, alternate contact Tet of the switching relay SV conductors 5O, 44 and to the other side of battery B. The switching relay SlV is now held energized independent of the contact 4-8 of the relay EGR. When the switching key SK was -movedto its emergency position E]? to close its contacts 37 and 38, one portion of the .energizingcircuit of the vibrator magnets VM and VM of the units 0 and P of the emergency pole changer C is closed, but due to the fact that normal contact 48 is open due to the fact that the relay ESE is in an energized condition while the pole changer A is in operation the energizing circuits of the vibrator magnets Viv P and VM are held-open, but upon its de-energi- 'zatio'n, the relays EOE closes its contact 48,

establishing an energizing circuit for the vibrator ina-gusts V11 2 and VM ,cf the units 0 and P of the pole changer C which may be traced from battery B, conductor 2, close contacts 3 mice of the battery BK, conductor 5, fuse 77 through the winding of the vibrator magnet VM of the unit- O of the pole changer C, interrupter cont-act 78-ofthe magnet VM conductors 79 and 80, conductorSl, closed contact 82 of the key switch a, conductors 83, 84 and 85, closed contact BS-of the switching key SK, conductor -73, normal contact 4-8 of the relay EUR, conductors 49, 50, 4E'and 15 to the other-side ofbattery B. The circuit of the vibrator magnet VM of the unit P of the pole changer C is traced from battery B, conductor 2, closed contacts 3 and 4C of key SK, conductor 5, fuse 77, conductor 86 through-the winding of the vibrator magnetfV-M, its interrupter contact 87, conboard with which the pole pole changer is in use.

ductor 80 to the other side of battery B over the path described in connection with the vibrator VM The closure of normal contact 48 of relay ECE also establishes an energizing circuit for the pole changer switching relays PR and PR, the circuitoi- EUR conductors i9 50. set and 15 to the a a 1 r The circuit oi the other side of battery T. pole changer switching relay PR may traced from the point 19 over conductor 26 through the winding of the relay Pit "and over conductor 89 to the other side 0t battery B as described in "connection with the relay PR. The relay PR upon energizetic-n closes its alternate contacts 23 and 55 tofswitch the windings 18 and 53 of the primary P ot'the transformer T from contacts and 51 of the vibrator magnet Viilof the pole changer A to the vibratory contacts 92 and 93 of the vibrator magnet VH of the unit 0 of the pole changer C, so that the vibrator VM which is now in vibratory circuit due to the opening and closing of its interrupter contact 78, passes current through the windings 18 and 53 of the primary P or" the transformer T. The relay PR upon energization closes its alternate contacts 29 and 59 to disconnect windings 18"and of the primary P of 'the transformer T from the contacts 31 and 52 of the vibr'ator magnet VM' of unit M, of

the pole changer A to the vibratory contacts 9% and'95 of the vibrator magnet Vlii of the "unit P of the pole changer C so that the windings 18 and 53 of the primary P of the transformer T may receive current. The induced current from the primary P of the transformer T and the primary P of the transformer T iiito the respective secondary windings 32 and 32 of the transformers Tand T again permitsalternating current at predetern'iin'ed cycles to pass over conductors 38, 3% and 35, 36 to the switchchanger (J is associated. The closure of alternate contacts lOiand 112 oi relays PH and PR switches the primaries 102 and 102 of the retardation coils RC and RC over conductor 113 and 114- in parallel with magnets VM and VM to permit a tone to be generated for delivery to the switchboard when Current also passes through the alternating current relays AC and AC "to again bring about their energization and the closing'oi their alternate contacts 09 and 40 again establishes an lic energizing circuit for the relay ECR and relay ECR upon energization opens its normal contact 4 8 but the opening 48 has no effect upon the energizing circuits of the primary relays PR and PR and the vibrator magnets VM' and VM of pole changer C as switching relay SW is locked in its energized condition through its alternate contact 7 1 and this alternate contact 74 also holds, as previously mentioned, relays PR and PR and magnets VM and VM energized.

Referring again to relay ECR which was de-energized when the relays AC and AG restore to normal, relay ECR upon de-energization closes its normal contact 115, and the conductors 116 and 117 which are connected to the contact 115 have associated therewith, a suitable alarm signal which operates when the pole changer A stops operating to notify the attendant at the exchange so that the pole changer may be repaired. For testing the pole changers A and C, I provide test keys TK and TK, the test key TK being associated with the pole changer A and the test key TK being associated with the pole changer C in the description. Having assumed that the pole changer C has been automatically connected, should the attendant wish to test the pole changer A, afterhaving taken care of the needed repair thereof, the test key TK may be operated to close an energizing circuit for the vibrator magnets VM and VM of the units M and N of the pole changer A, the circuit being traced from battery B, conductor 2, closed contacts 3 and 1, conductors 5 and 6, fuse 7 through the winding of the magnet VM, interrupter contact 9, conductors 10 and 11, closed contacts 118 and 119 of the test key TK, conductors 120 and to the other side of battery, The circuit of the vibrator VM is t 'aced over conductor 16 through the winding of the magnet VM, its interrupter contact 17 conductor 11 to the other side of battery, and vibrator magnets VM and VM' now operate over this circuit.

Assuming that the fuse 21 or 27 opens, this will open the battery circuit through either the windings 18 and of the primary P and transformer T, or the wind lugs 18 and 53 of the primary P of the transformer T, and as no further current passes through either of the windings P or P, as the case may be, the relay AC or the relay AC will be ole-energized. and the opening of either alternate contact 39 or 40 will bring about the operation of the circuit as already described in connection with the opening of the fuse 7.

I also provide a switching position 0 for the key K which position is associated with the operative circuit of the pole changer O and assuming that neither pole changer is operating and one desires to con ncct the poie changer C, the key K is moved to its position 0 to close contacts lei-O and 123 and operates starting key SK to close its starting contact 14-, key SK is moved to its starting position SP to close the initial energining circuit of the vibrator magnets VM and V1? from battery B conductor 2 closed contacts 3 and a, conductor 5, fuse 77, winding of the magnet VM' interrupter contact '78 of the magnet VM'- conductors 79 and 30, closed contact 1&0 of conductor 121, conductor 13, closed contact 1% of key SK, conductor 15, to the other side of battery B. The circuit of the vibrator magnet- PM extends over conductor 86 through the winding of M interrupter contact 87, con.- ductor 80 to the other side of battery. En. ergizing circuits for pole changer switclr ing relays PR and PR are also establishml the circuit of PR being traced from battery B, conductor 2, closed contacts 3 and a, conductors 5 and 20, winding PR, conductors 0'8 and 89, normal contact 90 of key TR, conductor 80, closed contact 110, conductors 121 and 123, closed contact lei, of key SK, conductor 15, to the other side of battery B. Relays PR and PR close their alternate contacts 23 and 55, and 29 and 59 to connect the primary windings P and P of the transformers 'l and T in connect-ion with the contacts 92 and 93 of the vibrator magnet VM and contacts 9% and 95 of the vibrator magnet VM Ringing current is now delivered to conductors 33 and 3 1 from transformer T at a predetermined cyle to the switchboard and to conductors and 36 from the transformer T at a pro-determined cycle to the switchboard. Relays AG and AG and ECR are operated as previously described. The key SK is now moved from its starting position SP to its emergency position EP, and closed contact 14 of the key SK is opened and substitute circuits for the magnets VH and VM and relays PR and PR are now closed and extend over conductors 121 and 45, normal contact as, of relay SXV conductor 17, alternate contact 18 of relay ECR, conductors 49, 50, and 15 to the other side of battery B, and the operation of the apparatus when pole changer C is operating from this point is readily apparent from the previous description.

Should pole changer Gst-op due to the opening of the fuse 77, the circuits of the vibrator magnets VM and VM would reopen and the alternating current relays 1C and AC and relay ECR will be de-energized and the'closure of normal contact &8 of the relay EGR will establish an energizing circuit for the vibrator and magnets VM and VM of the pole changer A over a circuit traced from battery B, conductor 2, closed contacts 3 and t conductors 5 and.

6, fuse 7, through the windings of vibrator magnets VM and VM' the interrupter contacts 9 and 17 of the magnets VM and VM, over conductor 11, conductor 122, alternate contact 123 of the key K, conductor 84, conductor 85, alternate contact 38, conductor 73, normal contact 48, conductors 49, 50, H and to the other side of battery B.

The closure of normal contact 48 of the relay ECR establishes an energizing circuit for the switching relay Sil over a circuitas previously described, and the opening of its normal contact 46 opens the circuits of the pole changer switching relays PR and PR. The closure alternate contact 7st of the relay SlV established a locking circuit for itself, as already described. The vibrator magnets VM and VM now operate and current through the primary windings P and P of the transformers T and "l" again delivering a predetermined cycle. of current to the conductors 34c and 35 connected 'to the transformer T, and conductors 3a and 35 which are connected to the transformer T. Relays AC and AC are again energized'as is also the relay ECR and the opening of normal contact as of relay ECR opens the initial energizing circuits of the magnets VM and VM, but as alternate contact 74 of relay SW is closed, the magnets VM and VM are energized through this contact independent of the contact 48.

Wit-h the switching system or" my invention it is readily apparent that either pole changer A or C may be used by simply moving the key K to either its a'or 0 posi- 'tion and that should either pole changer stop functioning for any reason depending on which one is operatingat the time automatic means are provided for instantly switching "to the idle pol'e'changer without any manipulation of keys or buttons thus eliminatingan interruption of the ringing current to the switchboard with which the p'olechangers are associated.

TV-hile I have illustrated and described aprefer'red embodiment ofmy invention, I do notwish to be limited "to this articular application of my invention as it may be Yused for a number'of purposes.

hat I claim as new and desire to secure by United States Letters Patent, is as followsz- '1. A switching system oi the character described including a pair of pole changers, each of which comprises two units, a key for rnani 1ailly controlling the connection of either pole cha ger, a switch for startin the operation GfSiLlCl pole c'hanger and con tr'ol means 00nd tinned by "said as; and operating "automaticallyl to switch from one pole changer {to "the-other.

' '2. A switching system of the character described including a pair of pole changers a They :for manually =congiecti each of which coniorises two units, a "keyfor manually controlling the connect-ion'o-t either pole changer, a s rite-h common to said pole changers for starting the pole changer connected by said key, said switch having an emergency position to which emergency position it moved from its starting position and control means conditioned by the movement of said switch to said emergency position ,to automatically switch from the pole changer in use to the other pole changer.

3. A switching system of the character described comprising 7 a pair of pole changers, a key for manually controlling the connection of either pole changer, a switch having a starting position and an emergency position, starting means i or said pole changer connected by said key w 7 said switch is moved to starting. posit n, and conditioning :means controlled lay said switch when moved from said starting 2P0- si'tion to said emergency position to switch from one pole changer to'athe other pole changer when the pole changer in use is disabled.

l. A switching system of the character described including apair-of pole changers each -'comprising two units, a :key f g neeting either pole changer lit, a switch for starting said pole changer cionn'e'c'ted by said hey, an emergency position for said switch to which itis moved from starting position, a pair of transformers common to said pole changers, and means controlled by said switch when in emergency position to switch the transformers from one pole changer to the other.

A switching system of the character described including a pair of pole changers, a key 'iior manually connecting either pole changer in circuit, a switch having a starting position tor starting said pole changer connected by said hey, an emergency position for said switch to which it is moved frol-n its starting position, a pair of transformers common to said pole changers, a pair of relays common to said t "dormers, and means controlled by said switch when :in' emergency position to cause the operation of said relay-s -whe nthe pole changer in =use is'disabled toaaultomat allyswitch said transformers trom the said pole changer to theiother pole changer.'

6. A sWitclring-syste n of the character described including a pair oi'po'le changers,

ither pole changer in circuit, a switch having {{1- start ing.jposition 'for starting said pole changer connected by iid keyfatinn "tor said *si itch to at from -:its"sta1 in'g *posi on, ffionners @011 n E t 1 o p'airoimel'ay oom 113}; to said a 1 t energized by current from trasiormers when the pole changer in use is operatin and means controlled by said relays for automatically switching the transformers from the pole changer in use to the second pole changer in case the first said pole changer is disabled.

7. A svitching system of the character described including a pair of pole changers, a key for manually connecting either pole changer, a switch for starting said pole changer connected by said key, an emergency position for said switch to which it is moved from its starting position, a pair of transformers common to said pole changers, a pair of relays common to said transformers energized by current from said transformers, a pair of relays common to said pole changers, and means controlled by said first pair of relays and the switch in emergency position to operate said second pair of relays to switch said transformers from the pole changer in use to the second pole changer.

8. A switching system of the character described including a pair of pole changers, a key for manually connecting either pole changer, a switch for starting said pole changer connected by said key, an emergency position for said switch to which it is moved from its starting position, a pair of transformers common to said pole changers, a pair of relays common to said transformers and energized by current from said transformers, a pair of relays common to said pole changers, a relay controlled by said first pair of relays, switching means controlled by said first pair of relays when the pole changer in use is disabled to effect said relay to operate said second pair of relays to switch said transformers from the disabled t'ansformer to the second transformer.

9. A system including a pair of ringing current supply devices, a key for connecting either of said current supply devices, a supply circuit, and a switch for conditioning automatic means for disassociating one of said devices in use from said supply circuit and for connecting the other one thereto.

Signed by me at Chicago, in the county of Cook and State of Illinois, this 28 day of Sept, 1923.

JOHN F. MEYERS.

Images