US1768745A - Control system - Google Patents

Description

July l, 1930. J. A. CLARKE, JR 1,768,745

` CONTROL SYSTEM Filed Nov. 30. 1927 3 Shets-Sheet l who @sa im 26%- @rou/1d Squence of ..5`w/7'c/7es Comb/baffo /Vo/ches WITNESSES: INVENTOR July l, 1930. J. A. CLARKE. JR 1,768,745 f CONTROL sYsTBl Filed Nav. so, 1927 s sheets-sneu 2 WMJ'M/ M2M I July l, '1930-4 l J. NCLARKE, JR 1,768,745

' common sys'rsl Filed Novf'so. 1927 I 3.suxsnot"z '50 7 'g s ap I zsf sof 2v" zaf JMG@ W- INvl-:Nfon

Patented July 1, 1930 g UNITED STATES PATENT OFFICE JOHN A. CLARKE, JB., 0F PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA CONTROL SYSTEM Application led November 30, 1927. Serialk No. 236,810.

My invention relates to` s stems of control for dynamo-electric mac ines and more particularly to the control of electric railway motors.

The object of my invention, generally stated, is the provision of a control system that shall be simple and efficient in operation and economically manufactured and installed.

A more specific object of the invention is to provide for the use of cam switches that are protected by unit switches or contactors to jointly set up the proper circuits to effect the operation of a plurality of motors in different arrangements and the transition from one arrangement to another during progressive movement of a controller in one direction.

A further object of the invention is to provide for the setting up of the proper circuits to suitably effect the operation of a plurality of ymotors in series and in parallel relation and'through a closed-circuit transi` tion from the one to the other.

Another object of the invention is to provide for effecting the acceleration of the motors during the parallel relation thereof by the cutting out of the resistance units in the sequence used duringy the series operation of the motors.

Other objects of the invention will, in part, be obvious and in part appear hereinafter.

The invention, accordingly, is disclosed in the embodiment thereof yshown in the accompanying drawing and comprises the combination of elements and arran ement of parts which will be explained in t e system hereinafter set forth, and the scope of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention, reference may be had to the following detailedfdescription taken in connection with'the accompanying drawing, in which:

Figure 1 is a diagrammatic view of the main circuits of a control system connected inl accordance with this invention; l f

Fig. 2 is a sequence chart of well-known form for indicating the preferred order of operation of the Various 'switches that are illustrated in Figs. 1, 3 and 4;

Fig. 3 is a diagrammatic view of the auxiliary or control circuits, which are connected 'and arranged in accordance with the features of this invention; and

Fig. 4 is a diagrammatic view of certain auxiliary circuits provided to permit multiple-'unit operation.

Figs. 5 to 11 inclusive, show dia rammatically the circuit connections estab ished during the transition from series to parallelmotor-circuit connections; and

` Fig. 12 is a diagrammatic view of the main circuit connections as they stand when the controller is actuated to position 15 to establish parallel motor circuit connections; and

Fig. 13 is a diagrammatic view of the motor circuit connectionsestablished after a predetermined number of motors have been isolated.

Although the circuits shown in Figs. 1 and 3 are both necessary to effect the complete operation of the control system, the features of the system may be more clearly set forth by describing the circuits separately. Consequently, the main circuit connections will first be described generally, in conjunction with the sequence chart and the illustrated auxiliary circuit connections will be set forthvlater.

-Referringnow to Figure 1, the system illustrated comprises suitable supply-circuit conducto-rs, such as trolley 25 and ground 26. As shown, four dynamo- electric machines 27 and 30, inclusive, of the commutator type, are connected in series groups of two each, in the circuit. It will be readily understood that, while only Vfour motors are shown in this particular diagram, any other number might be used and connected in pairs or otherwise.

The supply of current to the motors is controlled by a plurality of line switches 31 to33, inclusive, and the ymain motor circuits are controlled by n a plurality ofV lmotor switches 34 to 39, inclusive. As illustrated, a number of resistance units 40 to 50, inelusive, are provided for controlling the acceleration ot the motors when connected in the various arrangements, such as series and parallel.

The resistance units may be cut into and out of the motor circuits by means of switches 5l to 60, inclusive. These resistor switches are of the unit type and adapted for the making and breaking of circuits in which large currents are flowing.

In order to establish the desired grouping of the motors and the proper circuit arrangements, cam switches 61 to 73, inclusive, are pr vided and are operated, when the motors are cle-energized, by means of a controller 74 and the auxiliary circuits shown in Fig. to set up any predetermined motor circuits to permit series and parallel operation of the motors. After the proper circuits have been set up, the main motor circuits are closed or broken by means of the motor switches 34, 35, 37 and 39, inclusive, which are of the unit type and adapted for breaking circuits carrying heavy currents.

Referring now to the sequence chart, Fig. 2, it will be noted that when the controller stands in its off position, the cam switches 6l and 64, which are operated in a manner to be hereinafter described, are closed. Further, ono of the two groups of cam switches 66 to 6i), inclusive, or 7 O to 7 3, inclusive, is also closed, these switches being controlled by the setting of `the reversing drum 100, which is provided for changing the flow of current in thc motor field windings. Assume that it is desired to operate the motors in what for convenience will be designated the forward direction; then, upon setting the reversing drinn 100 in its forward position, cam switches 66 to 69, inclusive, are closed.

lVhen the controller 74 is advanced one notch, the line switches 3l to 33, inclusive, the motor switches 35 and 3S, and resistor switch 36 are closed. Current now flows from the trolley 25 through the line switches 3l to 323, inclusive, resistance units 46 to 50, and 45, inclusive, resistor switch 36, resistance units 40 to 44, inclusive, motor switch 35, the armatures 27a and 28a of motors 27 and 2S, respectively, cam switch 6l, motor switch 3S, the armatures 29a and 30a of the motors :29 aud 30, respectively, cam switch G8, motor field windings 29]c and BOf, cam switch 6), motor cutout switch 76, cam switches 64 and 66, motor field windings 27,1" and 23,2", cam switch 67, and motor cutout switch 75 to ground at Q6. The motors are now connected in series relation and are set in operation. As the controller 74 is advanced step-by-step, the resistance units 40 to 50, inclusive, are cut out in the desired sequence, as indicated in the sequence chart Fig. 2. Then the last notch of the series operation is reached, the motor switches 34 and 37 are closed.

The continuance of the progressive notching of the controller 74 eil'ects transition from the series connections ofv the motors to parallel connections. '.l`he transition is accomplished without opening all the motor circuits in a manner that will be hereinafter set forth.

As the controller 74 advances step-by-step, the cam switches 62 and 63 are closed, then the motor switch 3S is opened aud the cam Switch closed. When the controller reaches the last point of the transition, the motor switch 39 is closed. It will be evident that the opening of the motor switch 38 prior to the closing of the motor switch 39 will prevent all possibility of establishing a short circuit through the motor switches 39 and 38 to ground.

The motors are now connected in two series groups and the groups in parallel. Motors 27 and QS are included in one series group, with motors 25) and 8O in another.

The circuit for motors 9.7 and 28 includes the trolley 25, line switches 31 to 2li-, inclusive, motor switch 34, resistance units fl() to 44, inclusive, motor switch 35, motors Q7 and Q8, cam switches 62, 63 and 66, field windings 27] and 28j', cam switch G7 and switch to ground. It will also be observed that the circuit for the motors Q9 and 30 includes the trolley 25, line switches 31 to 33, inclusive, resistance units 46 to 50, inclusive, motor switches 37 and 39, the armatures of the motors 29 and 30, cam switch 68, field windings 29] and lOf, cam switch 69, switch 7G and cam switch G5 to Ground.

As the controller continues its Forward movement, the resistance units are cut out in a predetermined sequence, as indicated in Fig. 2. It will be noted that when the motors are connected in arallel relation, the resistance units are divided into two groups 40 to 44, inclusive, and 46 to 50, inclusive. In order to maintain proper halance in the circuits, a resistance unit is first cut out of one group, and then another out of the other group, such, for example. ai: when resista-nce unit 44 is cut out oi the tirst group, then resistance unit 5() is cut out of the other group ou the next step of thc controller.

Referring now to Fig. 3, it will be observed that the controller 74 comprises two Contact segments 74a and 74?) so shaped as to suitably co-operate with a plurality of Contact fingers 77 to 96, inclusive, to set up certain motor circuits in the desired :Z-equence. The circuits that are established and broken by the different parts of contact segments 74a and 741; will be specified from time to time as the description proceeds.

As shown, the Contact fingers '77 to 9S, inclusive, are connected to conductors that are desi nated by corresponding numerals and to t e various switch coils and contact Loo members, as will be hereinafter set forth. The contact fingers and the corresponding conductors leading therefrom are designated by the same numerals in order to simplify the detailed description of the control system. i

The electrical energy necessary for the operation of the various switches and control drums may be obtained from any suitable source through the main conductor 99. The source of supply may be a storage battery or a motorenerator set.

A reversing rum of a well-known type is provided for controlling the arrangement of predetermined circuits, whereby the ow of current in the motor-field windings may be reversed in order to rotate themotors either in a forward or a reverse direction. As isy usual practice, the reversing drum is interlocked with the controller. Further, when the reversing drum 100 is set in its forward position, an interlock drum 101, which is disposed for operation simultaneously with the motor field-winding reverser 100, is also set yin its forward position through the energization of a coil 102. A coil 103 may be energized by throwing the reversing drum 100 into its reverse position to effect the ,setting of the interlock drum 101 ofthe motor field-winding reverser 100 for reverse operation of the motors 27 to 30, inclusive. These coils 102 and 103 preferably control the actuation ofthe magnet valves of a. separate air engine provided for rotating the interlockl drum 101.

The reversing drum 100 includes a plurality of contact segments 104 to 111, inclusive. The contact segments 104 to 107, inc1usive,care disposed for engaging Contact fingers 112, while the contact segments 108 to 111, inclusive, are arranged for engaging contact fingers 113. f

f As will be observed, a control andcircuit breaker resetting switch 114 is interposed between the source of current 'supply and the reversing drum 100. A conductor 115 is provided for connecting kthe control switch 114 to a-contact finger that is located between the contact segments104 and 105 of the reversing drum.

Assuming that it is desired to move the locomotive in the forward direction, the reversing drum 100 is thrown into its forward position F, thereby operating contact segment to establish connection between the conductors 115 and 81. At the same time, the contact segment 110 engages two of the contact fingers 113 and establishes a circuit from the control switch 114 through conductor v97, .which is connected to the contact finger 98 of the controller 74 by means of ya contact plate l117, which is disposed to bridge the contact fingers 97 and 98 when the controller is in its off position.'

When the control switch 114 is thrown to the right, as viewed in Fig. 3, the conductor 116 is energized. In this manner, a circuit is completed through the parallel-connected actuating coils 1l8a, 1185, and 1180 of a plurality of series-related circuit-breakers 118 and a conductor 148 to ground at 131, whereby the circuit-breakers are closed.

After the reversing switch 100 has been operated and the control switch 114 is thrown to the left, the conductor is energized. The controller 74 may now be operated step-by-step to effect the setting up of the necessary motor circuits for the series operation of the motors. As will be seen, when the controller is moved to notch 1, the contact segment 74a bridges the cony tact fingers 77 and 78 while the contact seg vment 741) bridges the contact fingers 80, 8l,

82 and 87.

In this manner, a circuit is set up from the source of power supply, through the conductor 99, control switch 114, conductor 115, contact segment 105, conductor and contact finger 81, contact segment 74h, conductor 82, contact segment 106, conductor 120, contact segment 119 provided on the drum 101, and conductor 78 to contact segment 74a, thereby energizing the latter.

When the contact segment 74a is energized, current flowsthrough conductor 77 and the coil 121 of a magnet valve that is provided` for controlling the operation of preferably an air engine of a well-known type, which is dis osed to rotate an interlock drum 122. s ywill be observed, this drum is provided with a plurality of contact members 123 to 128, inclusive, that are disposed to set up predetermined control circuits, and is further provided with suitable cam members for actuating certain cam switches, thereby establishing the proper motor circuits for series and parallel operation. l

In this particular control system, the energization of the coil 121 effects the operation of the air engine to set the drum 122 in what isvk designated by the letter S as its series position. Thus, when the controller 74 is advanced to the'first notch, the drum 122 is immediately rotated to its position S. f

There is also a position designated P to which the drum may be moved to effect the establishment of themotor circuits required for parallel operation of the motors.

As indicated by dotted lines, there are a number of intermediate positions through which the drum passes as it rotates from` P to S or vice versa.

Further, the cam switches 61 and G4 are disposed to be closed by-the cams operated with the drum 122 as it rotates toward its S position and they are rretained closed as long as the drum remains set inl its series position. 'The cam switches 66 to 69, in-

elusive, were closed when the coil 102 was| energized upon the setting of thc reversing drum 100. Consequently, the. proper motor circuits are establil'iet. Yfor the s' fies operation of the niotors, and upon the closure oi" the protecting line and motor switches, the current flows as previously traced.

Another circui up when the coi irollcr 74 is moved to its i is 'from the energized .ct segment .n rhrengh contact finger and conductor 37, the actuating coil of the switch 35 and cnt-ont wirh 13V` to ground at 131, whereby the ci: fure ot' the motor switch 35 is effected.

As shown, an Vint irlocl 35i-in is provided on the switch and servesy to establish a connection between act ting coil of switch 3S, and a cut-out switch 132 that is connected to ground at 131. Since the drum 122 is in series position, the actuating coil of the switch 33 is connected to the conductor 37 and energized when the switch 35 is closed, thereby closing the switch 38.

the

In order to effect the el ire of the line switches 31 to 33, inclus iUeiloc;

3S in, operated by the sw l i vided and disposed. to cstabl a connection between the energized cer ctoil 7 8 and a contact finger 134, which 1s positioned to engage contact plate 127 when the drum 122 is in its series pos tV i Another contact finger 134, which is disp l to engage plate 127 when the drum. is in series position, is connected to the actuating coils of the switches 31 to 33, inclusive.

Current now flows from the energized conductor 7S, through interlock 3S-in, two of the contact fingers 134 that are bridged by the contact plate 127, the coils of the switches 31 to 33, inclusive, two of the contact fingers 134 that are bridged by the contact plate 128, two of the contact terminals 136 that are bridged by the interlock -out when the switch 60 out, and the circuit-breakers 113 to ground at 131. In this manner, the line switches 31, 32 and 33 are closed.

Another circuit set up when the controller is advanced to notch 1 extends from the energized contact segment 745, through conductor 80, and the actuating coil of the switch 3G to ground, to effect the closure of switch 36. Therefore, on the actuation of the controller 74 to the first position,` the line switches 31 to 33, inclusive, and the motor switches 35 and 39 resistor switch 3G are closed. Since the series motor circuits were partially established when the drum 122 was rotated to its S position, the closure of the line and motor switches sets the motors in operation.

As will be observed, the contact segment 74?) is stepped so that the conductors will be energized in the following order, 88, 89, 83, 90 to 96, inclusive. Consequently, the

pro-

operating coils of the switches 51 to 60, inclusive, are energized to cut out the various resistance units in a predetermined order. In this manner, the motors, while connected in series arrangement, may be accelerated step-by-step.

When the controller is moved to position 12, as indicated in Fig. 3, the contact fingers 84 and 85 are engaged by the contact segment 7 4b and the corresponding conductors are energized. Current now flows through the actuating coils of the switches 34 to 37, inclusive, and effects the closure of the latter.

Assume now that it is desired to set up the proper circuits for parallel operation of the motors 27 to 30, inclusive. In order to effect transition from series to parallel, the progressive movement of the controller 74 is continued. For convenience in description, the movement of the controller through transition will be divided into six steps. As will be noted by reference to the sequence chart, Fig. 2, these steps are designated A to F, inclusive.

As shown, the contact segment 746 is out away so that when the controller reaches position A of the transition, the contact fingers 91 to 96, inclusive, 83 and 84 are disengaged, thereby effecting the de-energization of the corresponding conductors. Consequently, the switches 51 to 54, inclusive, and 56 to 59, inclusive, are opened, introducing the resistance units 41 to 44, inclusive, and 46 to 47, inclusive, into the motor circuit. At the same time, the contact finger 8() is released from the Contact segment 746, thus de-energizing the. corresponding conductor and opening the switch 36.

The contact segment 74a is cut away so that the Contact finger 77 and the corresponding conductor are de-energized, thereby cutting off the supply of current to the actuating coil 121 of the magnet valve for controlling the drum 122.

It will be observed that a depending portion is provided on the contact segment 74a of the controller that engages contact finger 79, energizing the corresponding conductor. Current then flows through conductor 79, the contact fingers 134 thatare bridged by the contact plate 125, an actuating coil 137 of an inverted magnet valve which controls the operation of the air engine of the type shown in Patent 1,229,543 that is provided for rotating the drum 122. The energization of the coil 137 effects the opening of a magnet valve causing the air engine to rotate the drum 122 from its series position to its parallel position P.

Considering now step B of the transition, the cam switches 62 and 63 are closed as the drum 122 rotates to its P position. As will be observed by reference to Fig. 1, the

i :in

, ing coil of the switch 38.

closure `of switchesk 62 and 63 tem orarily short- circuits motors 29 and 30. urther, the rotation ofthe drum 122 to its lP posi,`

tion effects the release of the contact gers 134 that are bridged by the contact to 33, inclusive, may be supplied through a holding circuit comprising interlock 31-in,

which establishes connection between the i conductor 78 and the operating coils of the line switches Since a circuit from the energized conductor 78 to the actuating coils of these switches is establishedthrough the interlock 31-in, the circuit through the late 127 may be opened without opening the line switches.

Asythe drum 122 continues to rotate after the release of the contact fingers from plate 127, the contact fingers that are brid d by the contact plate 123 are released, t ereby effecting the de-energization of the actuat- The opening of the switch 38 is accomplished before the closing of the switch 39, preventing all possibility of establishing a short-circuit through the switches 38 and`39 to ground. Further, when the switch 38 is opened, the interlock 38-in is o cned.

When the control er 74 reaches positionk C during thetransition, the contact finger 86 is engagedk bythe contact segment 741), thereby energizing the conductor 86 and closing the switch 54. The purpose of closin'gthe switch 54 will appear hereinafter. Cn the next step D of the transition, the cam switches 61 and 64 are opened, effecting the separation of the two groups oi?y motors. Since the motors 29 and 30 are short-circuited, the switches ma be opened without breaking any energize motor cir cuits.

`The contact lingers 134, bridged by the contact plate 125, are now released. Since the switch- 38 is open and an interlock 38-out connects the conductor 79 to the coil 137, the breaking of the circuit through the plate 125 does'not effect the de-energization of the coil 137k or an interruption in the rotation of the drum 122.

Considering now step E of ythe transition, the drum 122 is rotated far enough to close the cam switch 65. Finally,-when the drum 122 reaches its parallel position, the contact fingers 134 that are 'connected to the operat' ingr coils of the switches 35 and 39, respectively, arc bridged by the contact plate 124. Current then flows from energized conductor 87, through the contact fingers 134 that are bridged by the contact plate 124, the actuating coils of the switches 35 and 39 and switch 132 to ground at 131. *y y As will be observed, the contact plate 128 when switch 31 is closed.y

56 to 59, inclusive.

isi of sufficient sizetomaintain continuously, lduring the rotation of the drum 122 from its series .to its parallel position,l the operating circuit of the switches 31 to 33, inclusive. Duringthe rotation of the drum, it picks up one of the contact iingers 134 before it drops another, thereby assuring the continuance of thc switch-actuating circuits.

It will be noted that the interlocks (SO-in and (iO-out, operated with the switch 60,

are provided for connecting the actuating coils of, thev switches 31 to 33, inclusive, directly to ground at 131,.when the switch is closed and through the circuit breakers 118 lwhen the switch 1s out.

lAs will be readily understood .from an examination of the diagram shown in Fig. 3'on the final step F of the transition, the closing of switch 39 connects the motors for operation in parallel relation. As the progressive operation of the controller' is continued, a stepped portionprovided on the ycontact segment 74() effects the energization of the conductors 91 to'96, inclusive, in sequence, thereby energizing the actuating coils of the switches 51 to 53, inclusive, and Thus, the resistor switches are closed in order and a step-bystep acceleration ofthe motors, while connected in parallel relation, is effected.

This process of changing from series to lparallel-motor-circuit connections is generally termed a closed-circuit transition, since the Lmotors 27 and 28 are continuously connected to the power source ywhile the motors 29 and 30 are shunted.

Assumin that it is desired to change from paral el to series-motor-circuit connections, then the controller .is actuated .toward its off position. The drum 122 vstands in its parallel position and can not be actuated to its series position until the magnet 121 is energized. It willbe observed that aninterlock 3l-out carried by the line switch 31 controls the actuating cir-k cuit of the magnet 121. Therefore, the magnet 121-can not be energized until the line switch 31 is opened. The opening of the line switch can not be affected until the controller yreaches its olfk position. The closure of the switch 38, for connecting the motors in series-circuit relation, depends on the position ofL the drum 122. When the drum is in its series position, an actuating circuit for the vswitch 38 is estab-` lished through the contact se ment 123 which bridges avpair of contacty ngers 134. Therefore, the actuating circuit for the switch 38 can not be established as long as the drum stands in its parallel position.

Therefore, the switch 38 can not be closed to establish series-circuit connections for the motoruntil after the controller is actuated to its olf position, opening the line switc 31. l

lVhen the controller reaches position 21, an extension et' the contact segment 74b engages the contact finger 80, thereby effecting energization of the conductor 80. Current now fiows through the actuating coil ot the switch 36 to ground at 131. The closure of switch 36 establishes a circuit from the main source of supply through line switches 31 to inclusive, switch 34, and switches 3G, 55, 37, and 35, to the motors.

Assume that for some reason, such as the short-circuiting of the windings of one of the motors 27 or 28, it becomes necessary to cut out this pair oi motors. Under such conditions, since the motors 29 and 30 are connected in series, it is desirable to retain the connections esta lished for the parallel operation of the motors and to effect their acceleration by the use of the same number it resistance units that was provided for use during the series operation of the motors.

In order to provide tor the complete isoation ot one pair ot the motors, a plurality of cut-out switches and 76 with control cut-eut sv-fitches 1130 and 132 are provided. Further, as shown, two cut-out interlocks 140 and 141, which are closed when the control eut-ont switches 13() and 132 are inserted in the conductor 7 7. 1t will also be observed that two more interlocks, 144 and 145, which arc closed upon the opening of the cut-out interlocks 140 and 141, respectively, are provided for interrupting a conductor extending between conductors 77 and 79. The interlocks 144 and 145 are arranged in parallel relation, so that by their independent operation the circuit between the conductors may be closed. An interlock til-out, which is disposed to break the conductor 77 when the'line switch 31 is closed, serves to establish the circuit through the cut-out interlocks 140 and 141 when the line switch is out and all the motors are connected in the circuit.

Since it is desirable to eifect the closure oi the interlock 54-in when the contact plate 14S is in its parallel position, two more interlocks, arranged in parallel relation, are connected between conductors 83 and 86 and disposed tor actuation to their closed positions to complete circuits when the eut-out switches 130 and 132, respectively, are opened. It vill be noted that the cut-out plate 14S, when set in its series position. establishes a connection between the conductors 83 and 86.

As set forth above, interlocks .140, 144 and 146 are associated with the cut-out switch 132. In practice, a variety of constructions may be provided for effecting the actuation of the differentinterlocks, as described, when the cut-out switches 130 and 132 are actuated.

A suitable construction may be made by providing springs, two of which tend to retain continuousl the interlocks 14() and 141 in their closedY positions while the others continuously tend to hold the interlocks 145 to 147 open. It will be readily under stood that means may be associated with the cut-outl switches 130 and 132 or with harriers mounted over them to compress the springs of the interlocks 140 and 141 and to extend the actuating springs of the interlock 145 to 147, inclusive, as the cut-out switches are opened, Therefore, the interlocks may be actuated by the operation of the cnt-ont switches.

In order to isolate, say for example, the motors 27 and 28, the cut-out switch 13() is operated. This permits the spring-actuated interlock 140 to open and the interlocks 144 and 146 to close. In this manner, the circuit through the actuating coil 121 of the magnet valve is interrupted and the coil (le-energized. Further, upon the closure of the interlock 144, connection through conductor 142 is established between the conductor 77 and the conductor 79. It will also be noted that the closure of the interlock 146 establishes a connection between the conductor 83 and the conductor 86. The switch 75, which is generally manually operated, is opened when the switch 130 is opened.

Assume that the controller 74 is in its olf position and the reversing drum in its neutral position when the eut-out switch is opened. Then, in order to set the motors in operation, the reversing drum 100 is moved to its forward position and the controller advanced to notch 1. The contact segments 74a and 745 are then connected to the supply conductor 92) and the conductors 77, 8() and 87 are energized.

The interlock 144 is in a circuit which is established from conductor 77 through iuterl ck switch 144, conductor 142, conductor 79, interlock 3Sout, actuating coil 137 of the inverted magnet valve that controls the llow of fluid pressure to the air-engine, contact plate 128, contact plate 135 and circuitbreakers 118 to the ground 131. Consequently, the air engine is set in operation and it rotates the drum 122 from its series position to its parallel position. The rotation of the drum effects the opening of the cam switches 61 and 64.

1V hen the reversing drum is set, the drum 101 is also rotated to its forward position. The simultaneous operation of the reversing drum and the drum 101 may be accomplished in any suitable manner, such, for example, as by the use of a mechanical connection.

Since the drum 101 is set in its forward position, the cam switches 66 to 69, inclusive, are closed.

It will be observed that when the drum Ult! y motors. f e

Another circuit is established from th energized conductor 79, which is now connected to conductor 44 throu h the interlock 139, the contact fingers 134 t at are bridged by contact plate 126, the actuating coils of the line switches 31 to 33, inclusive, the contact fingers 134 that are bridged by the contact plate 128, an interlock 149, which is associated with the switch 59 yand is disposed to complete the circuit through the contact plate r135 when the line switch 59 is out, and the circuit-breakers 118 to the ground 131. Therefore, the line switches 31 to `33, inclusive, are closed. Consequently, the main motor circuit is closed and current flows from the trolley through line switches 31, 32, and 33, the resistance units 46 to 50, inclusive, resistance unit 45, line switches 36, resistance units 40 to 44, inclusive, the motor switch 39, motors 29'and 30 connected in series-circuit relation, cam switch 68, field windings 29a and 30a, cam switch 69, switch 76 and camy switch 65 to ground' at 26.

It is pointed out that the interlock 54i-n serves to assure the completion of the circuit through the line-switch actuating coils in case the drum 122a, which rotates with the drum 122, does not actv quickly. The interlock 54--in further insures the maintenance of the circuit for energizing the coil .137.

Therefore, when the motors 27 and 28 are isolated, the same motor circuit will ber established for motors 29 and 30 connected in series that is established when the two motor groups are connected in parallel circuit relation, with the exception that the resistors 40 to 50, inclusive, are connected in seriescircuit relation. Thea'cceleration of the motors isv effectedv b a progressive movement ofthe Acontroller 4 to cut out the yresistance units 40 to 50, inclusive, in the same sequence as when the motors 27 to 30, inclusive, are connected in series relation.

Assume that a short-circuit occurs in motor 27 when the motorv groups 27--28 and 29-30 are connected in parallel relation. Underk such conditions the circuit-breakers 118 will open. Then,-in order to isolate motors 27 and 28, the' switch l130 is opened, permitting the actuation of the corresponding interlocks.

It will be readily understood from the preceding description, that the parallel drum 122 will be retained in its parallel position and theswitch 39 closed. Then, upon thc movement of' the controller to its off position to venergize the coils 118@ to 1180, inclusive, to close the circuit-breakers 118, the resistance units will be connected as for series operation of the motors. Consequently, as the controller is advanced, the motors 29 and 30 will be accelerated as in series operation.

In order to adapt the control system for multiple unit operation, all of the conductors 77 to 97, inclusive, except 81 and 82, are extended, as shown. In this manner the conductors may be connected to corresponding conductors in another motor vehicle. Control of the circuits may be effected by the operation of a single controller by making certain additions to the above-described system.

As shown in Fig. 4, these circuit changes comprise the severance of conductor 77 above the interlock 143. The upper portion of the conductor is then connected to provide a circuit through the actuating coil of the relay 150 andtheconductor 153 to the common conductor 148 leading to ground at 131. c In order to effect the energization'of the actuating coil 121, a circuit is provided through the interlock 143, the relay 150 and conductor 149 to the conductor 78, which is always energized when the controller has been advanced from its off position. It will be observed that this does not affect the operation of the control system, since the coil 121 will be energized as before when the contact` finger 77 engages contact segment 74a, inasmuch as the conductor 78 is alwaysy energized when the controller is advanced from the ofi position, and current will flow through coil 121 whenever the relay 150 is closed.

The conductor 79 is opened above the point where it is joined by the conductor 142 leadin from the cut-out switches 144 and 145. circuit is then established from the conductor 79 through the actuating coil of the relay 152, conductor 154 and the commonline 148 to ground at 131. The lower portion of the conductor 79 is connected through the relay 152 to the conductor 78. Since the relay 152 is actuated only upon the energization of conductor 179, the functioning of the coil 121 will be the same as already described. e

Since various changes may be made in the above-described rconstruction and arrangement of parts, and different embodiments of the invention may be made without departing from thescope thereof, it is intended that all matter contained in the above description or shown in theaccompanying drawings shall be interpreted as illustrative and not in a limiting sense.

l claim as my invention:

l. ln a control system, the combination with a plurality ot' dynamo-electric machines, or' a plurality of cam switches operabie to set up predetermined circuits to provide Yfor series and parallel grouping oit the maell unit switches disposed to close said circ-uns, a controller co-operativc to ellect, through a single progressive Inovevaient, the actuation ot said switches, and means effect-dn'T a closed-circuit transition of the machines from series to parallel relation,

In a control system, the combination a plurality of dynamo-electric maor a plurality et cam switches oper- 'edetermined circuits to proid parallel grouping of the I, switches disposed to close s; i circuits, a controller' co-operative to e ect, through a. single progressive movethe actuation oi' the syvitones, and

for isolati 'i 3. In a control system, the combination with a plurality of motors, of cam switches operable to set up dill'erent circuits to group moors in series and parallel arrangements, a plurality of resistance units disd to be cut into and out oit the motor s to control the acceleration or the .fm unit switches for closing the motor rits, and a controller co-operative to t, through single progressive movethe actuat on ct said switches, said suitciies bei adapted to establish a s ce; and a parallel relation of the resistance units.

la a control system, the combination 'with a pluralityv of motors, of cam switches operable to set up dii'erent motor circuits to group the motors in series and parallel arrangements`r a plurality of resistance units dispo ,d to be cut into and out of the motor circuits to control the acceleration of the motors, units switches for closing the motor cuits, a controller co-operative to etl'ect, through e si* rle progressive movement, the d switches, and means for Y rmined number of the mot, is, sa. ,i isol g means being disposed to cooperate Witn the controller to control the establishment of circuit connections for operating the remaii 'ng motors.

5. In a control system, the combination with a plurality of motors, ot cam switches operable to set up different circuits to effect any desired grouping of the motors, unit switches for closing the motor circuits, a controller co-operative to eil'ect the actuation of said switches, and means for isolating any predetermined number of the motors, said isolating means being disposed to cooperate with the controller to eiect the establishment of motor circuit connections for operating the remaining motors.

6. In a control system, the combination with a plurality of motors. of cam switches operable to set up different circuits to group the motors in series and parallel arrangements, unit switches for making and breakin r said motor circuits, a controller co-operative to effect the actuation of the switches to establish series and parallel connections for the motors, and means cio-operative to maintain a closed-circuit transition of the motors from series to parallel relation.

7. In a control system, the combination with a plurality of motors, of cam switches operable to set up different circuits to group the motors in series and parallel arrangements, unit switches for making and breaking said motor circuits, a plurality of resistance units disposed to be cut into and out of the motor circuits to cont-rol the acceleration of the motors, means co-operative to establish a series and a parallel relation of the resistance units corresponding to the series and parallel connections of the motors, a controller adapted to effect, through a single progressive movement, the actuation of said switches, and means cooperative to maintain a closed-circuit transition of the motors from series to parallel relation.

8. In a control system, the combination with a plurality of motors, of cam switches operable to set up different circuits to group the motors in series and parallel arrangements, unit switches for making and breaking said motor circuits, a plurality of resistance units disposed to be cut into and out of the motor circuits to control the acceleration of the motors, means co-operative to establish a series and a parallel relation of the resistance units corresponding to the series and parallel connections of the motors, a controller adapted to effect, through a single progressive movement, the actuation of said switches, and means for isolating a predetermined number of the motors, said isolating means being disposed to cooperate with the controller to establish a combination of the series and parallelcircuit connections to provide for connecting all the resistance units in series with the remaining motors.

9. In a control system, the combination with a plurality of motors, of cam switches operable to set up different circuits to group the motors in series and parallel arrangements, unit switches for making and breaking said motor circuits, a plurality of resistance units disposed to be cut into and out of the motor circuits to control the acceleration of the motors, means co-operative to establish a series and a parallel relation of the resistance units corresponding to the series and parallel connections of the motors, a controller adapted to eifect, through a single progressive movement, the actuation of said switches, and means for isolating a predetermined number of the motors, said isolating means being disposed to cooperate with the controller to effect the establishment of the parallel connections of the remaining motors and the series relation of the resistance units.

l0. In a control system, the combination with a plurality of motors, of cam switches operable to set up different circuits to group the motors in series and parallel arrangements, unit switches for making and breaking said motor circuits, a plurality of resistance units disposed to be cut into and out of the motor circuits to control the acceleration of the motors, means co-operative to establish a series and a parallel relation of the resistance units corresponding to the series and parallel connections of the motors, a controller adapted to effect, through a single progressive movement, lthe actuation of said switches, means for isolating a predetermined number of the motors, said isolating means being disposed to cooperate with the controller to control the circuit connections established to operate the remaining motors, and means co-operative to maintain a closed-circuit transition from the series connections of the motors to the parallel connections.

l1. In a control system, the combination with a plurality of motors, of cam switches operable to set up different circuits to group the motors in series and parallel relations, a plurality of resistance units disposed to be cut into and out of the motor circuits to control the acceleration of the motors, unit switches disposed for making and breaking the motor circuits, a controller cooperative to effect the operation of the switches, and means co-operative to effect a closed-circuit transition from the series to parallel relation of the motors and an opencircuit transition from parallel to series reulation maybe effected through the operation of one controller.

In testimony whereof, I have hereunto subscribed my name this fourth day of November, 1927.

JOHN A. CLARKE, Jn.

lation, said switches being adapted to establish series and parallel relations of the resistance units.

*12. In a control system, the combination with a plurality of motors, of cam switches operable to set up different circuits to group the motors in series and parallel relations, a plurality of resistance units disposed to control the acceleration of the motors, unit switches for closing the motor circuits, a controller co-operative to effect, through a ysingle progressive movement, the actuation of said switches, and means connected into said control system to permit its connection to a similar control system whereby manip-

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