US2669681A - Motor control prior to dynamic braking - Google Patents

Description

Feb. 16, 1954 c4. R. FURIFOY MOTOR-CONTROL PRIOR TO DYNAMIC BRAKING Filed Jan. 27, 1953 21. PROGRESS HOLD INVENTOR WITNESSES: 47 wd George R.Purifoy. BY

ATTORNEY Patented Feb. 16, 1954 BRAKING George R. Purifoy, Pittsburgh, Pa., assignor to Westinghouse Electric Corporatiom East Pittsburgh, Pa., a corporation of Pennsylvania Application January 27, 1953, Serial No. 333,546

3 Claims. 1

My invention relates to direct-current elec- 'trically propelled railway-vehicles, and it has particular relation to'eleotrical control-systems thereof, in which provision is made for dynamic braking. The principal object of my invention is to provide a new means or instrumentality for reducing the high buildup-rateand'overshooting "of the motor-current and the motor-voltage when the dynamic-braking circuits are" established while the'motors are bein 'operated at high speeds. Excessive motor-current and excessive "motor-voltage result not only in a rough brakeiapplication, but also in motor-flashing. My invention is an improvement over the control- "equipment which is shown in a companionap- 'plication of William L. Barclay, Jr., and myself, Serial No. 295,794, filed June 26, 1952, in which "other'means were provided for the purpose of mitigating overshooting when dynamic'braking is "applied.

1 have provided an auxiliary switching-segment or segments on the field-controller, for-taking care of an objectionable condition which sometimes occurswhen the motorman elects to operate the car or train, for a while, on either the switching position or the series running'position of the master controller, with the train running at speeds much higher'than the normal switching-speeds or the normal series-running speeds, and subsequently going into dynamic brake "from either said switching position or said series running position.

' With the foregoing and other objects in view, my'invention'consists in the circuits, systems,

apparatus, combinations, parts, and methods of design and operation; hereinafter describedyand illustrated in' the accompanying drawing;- the single figure of which is a simplified circuitdiagram'of the-parts of one car, which are neces- --sary to'illustrate my present invention,- omitting many parts which are known to be needed in a successful railway-control equipment of the type to which my invention is applied, but which are not necessary to he discussed in setting forth the nature and operation of my present improvement. The drawing represents some of the equipment which is carried by a single electrically propelled railway-car embodying my invention. 1 Theprincipal novel feature, as shown in the illustrated -form of embodiment of my invention, relates to the provision of contact-segmentsnfland 253 'onxthe field-controller FC, in addition to the contact-segment 306 which is shown insaid com- --panion-application.

Direct-current power is supplied to the car ment, carried by the car.

from a third rail Hi5, or a trolley wire, which is engaged by a third-rail shoe tile, or a trolley pole,

pantograph, or other current-collecting equip- The third-rail shoe 3% energizes a line IS"! which constitutes a supply-circuit for the car. The traction-motors for the car are series motors, which are indicated,

by way of showing a simple example in the'drawing, as'comprising two motor-armatures Aland A2, each being associatedwith its own series field winding SF! and SP2, respectively, the ordinary reversing-switches being omitted for thesake of "simplicity. Two'series-motor means, or circuits,

are shown. The first series-motor-means comprises, in series, an armature-terminal 'AI'l, a motor-armature or armatures Al, an intermediets connection point .AXI, a series field lwinding or windings SFI, for supplyingthe fieldexcitation for said armature or armaturesyrand a field-terminal Fll. The corresponding parts for the second series motor means are indicated at ATZ AZ, .AIQ, SF2, and FT.

A series-parallelmotor-control arrangement is shown in the drawing-in which a line-switch or vrelayLSl and a ground-switch GI are used as power-switch means for establishing apowercircuit for'energizing the motors, by connecting 1. the first armatureeterminal A'Il to the supplycircuit I91, and connecting the second armature- J terminal ATZ to ground. For completing :the

in addition to the power-switches LSI and'Gl. For parallel-motor operation, two switches M and series-circuit connections, a switch JR is.closed G are closed in addition to the power-switches LS! and Gt. The parallel-motor switch M provides a circuit-connection between the armatureterminal ATI of one series-motor means and the field-terminal FT of the other series-motor means; whilethe other parallel-motor switch G provides a circuit-connection between the. other armature-terminal AT2 and the other field- .terminal'FHj During an intermediate transition-period, a switch J is closed. These motorcontrollingconnections are all in accordance with a well-known switching-system. Dynamic-braking circuits are established by opening the two power-switches'LSl and (ii and closing a braking-switch Bl in addition to the two'parallel-connection switches M and G, also rangement.

inaccordance with a well-known system or-ar- The braking-switch Bl provides a common dynamic-braking circuit-connection I 98 between the'respective intermediate connectionpoints AX! and AX2 of the two series-motor mea.ns, thusproviding two dynamic-braking circuits wherein the motor-armature or armatures- S of each of said series-motor means are loaded by the field winding or windings of the other one of said series-motor means, respectively.

A progressively operating acceleration-controlling means is provided, in any suitable manner, including a first-operating voltage-controlling means for controlling the voltage which is efiective on the motor-armatures AI and A2. In the illustrated form of embodiment, this voltagecontrolling means comprises a suitable number of series-connected accelerating resistances, as indicated at RI, R2, R3 and R4. The resistance RI is disposed between the supply-line I91 and the first armature terminal ATI, and is shorted out by means of a second line-switch LS2. The resistance R2 is in series with the first field-terminal FI I, and is progressively shorted out by means of switch-contacts SI, S3 and S9. The resistance R3 is in series with the second fieldterminal FT, and is progressively shorted out by switch-contacts S2, S4 and Slil. The resistance R4 is in the series-motor connection which is made by the switch JR, and this resistance is finally shorted out by the transition-switch J, for obtaining the full-series power-circuit connection of the motors.

During parallel motor operation, the switchcontacts S3, S5 and S9, SIB are successively or progressively closed, during the acceleration of the motor, and after all of the accelerating-resistances R2 and R3 have been cut out, the acceleration-controlling means of my control-apparatus includes a finally-operating field-controlling means for progressively reducing the field-strengths of the motors, to provide shortfield operating-conditions.

In accordance with a usual arrangement, the motor-fields are reduced by equipping each of the series field windings SFI and SFZ with a field-shunt, comprising an inductive reactor XI or X2, as the case may be, and a variable resistor RSI or RS2, respectively. The field-shunts XI-RSI and X2-RS2 are field connected in parallel relation to their respective field-windings SFI and SP2, by means of contact-terminals II and I2, respectively, of a progressively or sequentially operating field-controlling means, which is herein illustrated as an electrically operated drum-type field-controller FC. After the respective field-shunts have been connected into operation, the field-shunt resistances RSI and RS2 are then progressively shorted out by successive controller-points I3, I5, IT and I9, for RSI, and I l, I6, I8 and 20, for RS2, as the fieldcontroller PC is moved from its initial full-field position FF, through its intermediate positions FI, F2, F3 and F4 to its short-field position SF,

at which point the field-winding currents are mentioned accelerating-resistances R2 and R3,

in establishing the complete dynamic-braking circuit. The braking-resistance R5 is progressively shorted out by means of braking-switches B2, B5 and B6, during dynamic-braking operations, after which the acceleration resistances R2 and R3, or portions thereof, are progressively shorted out, as by the switch-contacts S3, S4,

and s9, SI I1. (The switch contacts SI and s2 are permanently closed during the dynamic-braking operations, in the illustrated system.)

The progressive operation of the various resistance-shorting switches, during both motoring operation and dynamic braking, is under the automatic control of a suitable limit-relay or relays, which are energized to be responsive to conditions which accompany excessive torque in the motors. Such a limit-relay is illustrated in the form of a current-relay CR, having an actuatingcoil CR which is connected in series-circuit relation between the connection-point AXZ and the armature A2. This current-relay CR also has a back-contact I99 (also marked CR), which is normally closed, that is, which is closed in the non-actuated or low-current position of the relay.

The current-relay CR is also provided with certain recalibrating-means. In accordance with previous practice, this relay is provided with a cumulatively operating rate-coil RC, which in energized through a weight-responsive rheostat 280, during accelerating operations, and which is energized through a braking-responsive rheostat 25H during dynamic-braking conditions. The weight-responsive rheostat Zilll is automatically adjusted according to the variable weight or live load carried by the car, so that the ratecoil RC is the most strongly excited during lightload conditions, thus reducing the minimumcurrent setting at which the limit-relay CR picks up and opens its back-contact I99. The braking-responsive rheostat 21 is automatically changed in response to the position of a brakehandle 202, which will be subsequently described, so that the rate-coil RC has its maximum. excitation when a low braking-rate is called for, thus providing a low minimum-current setting at which the limit-relay CR picks up and opens its back contact I99, and also providing limitrelay calibration which is different from braking and power-operating conditions.

All of the electrically controlled relays and switches which are shown in the drawing are diagrammatically indicated as having vertical switch-stems (indicated by dotted lines), which are biased by gravity toward their lowermost positions, and all of these switches and relays are shown in their deenergized or non-actuated positions. All of the relays and switches are electrically controlled, and they are illustrated as being electrically or magnetically operated, by means of an appropriately numbered or lettered coil or solenoid, represented by a circle, acting magnetically to lift an armature which is represented diagrammatically by a smaller circle inside of the coil-circle. In general, the same switch-designation is applied to any particular switch, its coil, and its contacts, by way of identification of the parts belonging to a given switch or relay.

The various electrical control-circuits for a train are under the control of a number of trainline wires, which extend from car to car, throughout the entire length of the train (not shown). In the simplified circuit-diagram of the drawing, eight of these train-line wires are used, being given their usual designations, namely (I-) 3, 4. 5, 6, "I, I2 and GS.

Energy for the various relay-circuits or switchcircuits is provided by means of a battery B on each car. The negative terminal of each battery is permanently grounded, while the positive terminal of each battery is connected,

through a switch 203,120 the positive train-line wire , Each end of each car is provided with'a motor.- mans master controller MC, only one of which is indicated in the drawing. The illustrated master controller MC is indicated as being an accelerating-controller having an off-position and three on-positions 1, 2 and 3. In each of the three on positions of the master-controller, MC, the positive control-wire is connected to the train-line wires I2, GS" and 6. The trainline wire I2 is the energizing-wire for the operating coil LS! of the line-switch LSI;' while the train-line wire GS is the energizing-wire for the operating coil GI of the ground-switch GI, as will be subsequently described. 7

In'the second and third on-positions of the accelerating-drum of the master controller MC, the train-line wire 4 is energized from the positive bus while in the third on-position of this controller, the train-line wire I is energized from the positive bus (-1-) In the off-position of the accelerating drum or master controller MC, a connection is made from the positive control-wire to the trainline wire 3. In the master controller MC, in accordance with a known practice, there is an overlap between the off-position contact which energizes this conductor 3, and the on-position contactswhich energize the conductors I2 and GS, so that, during the notching-off of the master-controller MC, the contact at 3 is made before the contacts at I2 and GS are broken. This overlapping construction is particularly necessary in properly controlling a braking-oporation protective-relay 'BP, which will be subsequently described, and which also constitutes the subject matter of a Riley Patent 2,597,183, May 20, 1952.

The first on-position of the accelerating-con- 1 troller MC, in Fig. 1, is a switching position, in which the control-wires I2, GS, and 6 are all energized. The control-wire I2 energizes a control-circuit wire I0, through interlocks which are provided, by the braking-switches BI and B5, in the form of back-contacts 204 and 205, respectively; and the control-circuit wire I0 is used to energize the operating-coil LSI of the line-switch LSI.

Inaccordance with a usual practice, the exciting-circuit for the line-switch operating-coil LS! also contains a make-contact 206 of a linerelay LR, which is a voltage-responsive relay which drops out upon a voltage-failure ofthe supply-line 91. This line-relay LR is shown as an undervoltage relay which has an operatingcoil LR which is connected between the supplyline I91 and ground, through a back-contact 201 of the line-switch LS2, said back-contact 20'! being paralleled by a make-contact 208 of the line-relay LR.

As set, forth in an application of R. E. Burkhart and myself, Serial No. 269,752, filed February 4, 1952, the control-wire i0 energizes a control-wire I20 through. aback-contact'209 of the line-relay LR. This line-relay back-contact 209 thus closes in the event of a power-line voltage-failure, which might result from either a third-rail gap or from-any, other cause; and if the master-controller MO is, at the time, on any on-position, the conductors I2 and ID will be energized, and hence the line-relay back-contact 209 will energize the control-wire I20, which I-use as an auxiliary holding-circuit for the protective relay-or brakepowerrelay 'BP, which I will subsequently described, in more detail.

The train-line'wire GS energizes the operating-coil GI of the ground-switch GI, through interlocks which are provided by back-contacts 2I0', 2H and 2I2, which are carried by the braking-switches BI and B5, and by the parallel-0peration switch (3-, respectively. The back-contact 2I2 is paralleled by'a make-contact 2I4 of the ground-switch GI.

The train-line wire 6 is connected, through an LSI make-contact 2 I5, to a relay-circuit" 80, which is connected", through a GI make-contact 2I5, to a circuit 62 which constitutes a holdcircuit for the switch-progression for the accelerating-resistance short-circuiting switches SI to SIOand J. This hold-circuit S2 is used to energize'the'operatingcoil JR of the series-motor circuit switch JR, through interlocks on the switchesJ and G, in the form of back-contacts 2 I 'I' and 2-18, respectively.

According'to my present invention, 1 also-inelude; in the energizing-circuit of the JR-coil, a field-controller contact-segment 225, which is closed in the initial, fuli-field position FF of the field-controller PC, but which is opened when the-field-controller is moved to its short-field position or say when the field-controller moved from its second on-position F2 to its third on-positicn F3. As shown, the new'iield-controller contact-segment 228 is included in a circuit which extends between the hold-circuit;62 and a control-circuit G3 which in turn energizes the operating coil JR of the series-motor-circuit switch JR through the interlocks 211 and -2I8. The purpose of this contact-segment 220 will be subsequently described.

The said hold-circuit 62 is also used to directly energize the close-coil or actuating-coil BP-Close of the braking-operation protective-relay BP.

The result of the master-control energization in the No. 1 on-position of the master-controller MC,'is thus to close the main-circuit or powercircuit contacts of the traction-motor switches LSI, Gland JR, thereby completing a series-connection motor-circuit for causing a slow movemerit-of the train, for so-cailed switching purposes, with all'of the accelerating-resistances in series with the motors. This circuit can be traced from the supply-circuit I522, through the main LSI contact, the resistor the armature AI, the series'field SFi, the resistance R2, the resistance R4, the main JR contact, the resistance R3, the series field SP2, th current-re1ay coil OR, the motor armature A2, and the main GI contact, to ground.

At the same time-the energization of the braking-operation protective-relay BP paves the way for the subsequent energization of the dynamic- .brakingcircuits of the motors, and also for the automatic progression-control, under the control of the limit-relay or current-relay CR, both for the motoring progression during acceleration, and for the dynamic-braking progression during an application of the brake-lever 282, as will be subsequently described.

The hold-circuit 62, which is energized in the No. '1 on-position of the master-controller, is also connected, through an LSI make-contact 222, to a hold-circuit 6?, which is used in the subsequent progression-control.

The No. 2 position of the accelerating-controller MC is the first of two running-positions 2 and 3. It initiates the accelerating progression of the series+motor connections-by energizing the train-line wir 4, which is connected, through an LSI make-contact 224, to a conductor 40. The conductor 40 is connected, through an LS2 backcontact 225, to a conductor 42, which energizes the operating-coil LS2 of the second line-switch LS2, which acts as the first acceleration-progression switch, by short-circuiting the first accelerating-resistor RI. This LS2 switch has a makecontact 221 which picks up and serves as a holding-circuit contact between the circuits 60- and 42.

If there were any doubt about the adequate speed of closure of the series-motor-connection switch JR, the energizating-circuit for the first resistance-shorting switch LS2 could have included a JR-interlock (not shown in my drawing), to make sure that the JR-switch was closed, before the LSZ-switch is energized, thus avoiding the possibility of skipping a resistance-reducing step because of the slowness of the JR-switch. as shown, for example, in the companion-application of Barclay and myself. In my present control-system, as will be more fully described, I provide a progression-system wherein the parallelmotor connection is sometimes made without progressing through the resistance-reducing sequence of the series-motor connection, but I want the LSZ-switch to be closed, and hence I find it mor convenient to make sure that the JR-switch is faster than the first resistance-shunting switch LS2, thereby avoiding the necessity for a JR-interlock in the energizing-circuit for the resistance-shorting switch LS2.

This second line-switch LS2, which serves as the first resistance-shorting switch, also has a make-contact 228 which connects the circuit 40 to a circuit 45. The circuit 45 is connected, through the CR limit-relay back-contact 199, and through a BP make-contact 230, to a circuit 46, which constitutes the main limit-relay progression-circuit of the control-equipment. limit-relay progression-circuit 46 is thus not only under the control of the limit-relay or currentrelay CR, which is responsive to excessive motorcurrents, but it is also under the control of the braking-operation protective-relay BP, which must be closed (with the protective relay in its actuated position), before there can be any progression during either the motoring operation or the braking operation.

This limit-relay progression-circuit 46 is cont nected, through an LS! make-contact 23L to a progression-wire 4?, which is connected through an LS2 make-contact 232 to a control-wire 50. Th control-wire 5G energizes the operating-coil l-2 of a second resistor-shorting progression- A switch 1-2, which carries the two main contacts SI and S2, this energization being efiected through a back-contact 233 of this same switch l-2. Thus, this energizing-circuit from the conductor 50 includes the switch-out interlock 233, a conductor 5|, and the coil 1-2. This second progression-switch l-Z picks up and closes a holding-circuit make-contact 234', which energizes the circuit 5! from the hold-circuit 61.

The actuation of the second resistance-shorting switch i-2 also closes a make-contact 235, which energizes a circuit 53 from the progression-circuit 47, through a back-contact 2390f a third resistance-shorting switch 3-4, which is the switch which carries the main switchingcontacts S3 and S4. The energizing-circuit for this switch extends from the conductor 53, through the operating-coil 3-4 and a back-contact 23? of a fourth resistance-shorting switch 9-H thence through a control-circuit conduc- This 8 tor I09, and a J-switch back-contact 238, to the grounded negative battery-terminal The actuation of the third resistance-shorting switch 3-4 closes a make-contact 23-9 which establishes a holding-circuit for the conductor 53 from the hold-wire 67.

The actuation of the third progression-switch 3-4 also closes a make-contact 24!, which completes a circuit from the progression-wire 41 to a conductor 59, which energizes the actuating coil 9-!!! of the fourth resistance-shorting switch S-IB, which carries the main switch-contacts S9 and sit, the negative terminal of said coil 9l I) being connected to the previously described wire I09. The actuation of this fourth switch 9-) also closes a make-contact 242 which establishes a holding-circuit for the conductor 59 from the hold-wire 61.

The actuation of the fourth resistance-shorting switch 9-!!! also closes a make-contact 243, which is connected between the progression-wire 41 and a circuit 55, through a back-contact 244 of the third resistance-shorting switch 3-4. This circuit 65 energizes the operating-coil J of the transition-switch J, through a. G-switch back contact 245. The transition-switch J then closes its main or power-circuit contact J, which constitutes the last step in series motor-connection for the traction-motors, cutting out the last accelerating-resistance R4. This transition-switch J has a make-contact 241 which establishes a holding-circuit from the conductor 65 back to the hold-line 82. Th previously described J-switch back-contacts 2H and 238 are opened, upon the energization of the transition-switch J, thus dropping out the initial series-connection switch JR, and the third and fourth acceleratingswitches 3-4 and 9-H).

The next step in the acceleration of the traction-motors is accomplished by a movement of the master-controller MC to its No. 3 position, which is a parallel-motor running-position. This position 3 of the master-controller energizes the train-line wire I, which is connected, through a. back-contact 249 of the fourth accelerating or resistance-shorting switch 9-36, and a makecontact 250 of the transition-switch J, so as to energize a control-circuit 3|, which is in turn connected, through a JR back-contact to a parallel-connection control-circuit 56 which energizes the operating-coils M and G of the parallel-motor-connection switches M and G. These switches M and G thereupon connect the traction-motors in parallel, between the supply-circuit l9! and ground, with only the first two of the resistance-shorting switches energized, in the illustrated form of embodiment of my invention-namely the second line-switch (or first progression-switch) LS2, and the second progression-switch i-Z which carries the main switchlug-contacts SI and S2. The energization of the parallel-connection switch G opens the previously described back-contact 245, which drops out the transition-switch J. The energization of the parallel-connection switch M closes a make-contact 252, which establishes a holding-circuit for the conductor 66 from the line '60.

According to my present invention, in addition to the interlock 252 of the parallel-connection switch M, I also provide a new field-controller contact-segment 253, connected in parallel to said M-switch interlock 252. This new contactsegment 253 thus connects the relay-circuit to the parallel-connection circuit 66. Said contact-segment is closed whenever the acceleraclone-progression of. the traction-mctor control has advanced farienoughv (as will be subsequently described) to move the field-controller to. any position close to its shortefield position 5 say to any field-control po: tion bet F3. Th purpose of this field-controller contact'segment will be subsequently described.

Responsive to the dro,=; -ping--out of the transition-switch J (which was deener a result of the energization of the parallel-connection switch M), the back-contact 238' of this tra si" tion-switch recloses, and re-il "'atcs the switchprogression of the resistance-shorting contacts S3 to Sit, under the control of th "witches 3-- and 9-Hl, through the circuits r 11 have been previously described. This establishes the mash mum armature-voltage conditions on the motors, and it completes the connections for the full-field parallel-connection operation of the traction motors.

As soon as resistance-shorting switch B-lE!closes, it closes an additional contact which energizes a field-controller actuating-circuit from the progress-wire 4?, circuit extending from the wire through. the previously mentioned make-contact the of the resistanceshorting switch $49, a back-contact 2% of the third progression-switch 34, a make-contact 25! ofthe parallel-connection switch M, and a make-contact 258 of the line-switch LS2, thence, to the short-field wire as of the fieldcontroller FC.

The short-field wire 39 of the field-controller FC energizes the short-field coil FC-SF, or other means which may be used to move the field-con- 1':

troller from its full-field position F5 to its short field position SF. This starts the progressive operation of the field-controller, and it may be brought about in any oneof' several ways. In

the illustrated form of embodiment, since the .1

power for the short-field wire 39 is obtained fro .i the progress-wire 41, which is under, the control oithe limit-relay CR, the field weakening progression. of the field-controller FC progresses under the controlof the limit-relay CR, until the short-field position SF is reached. This completes the connections for the short-field parallelconnection operation of the traction-motors, thus completing the accelerati0n-progression If, now, the master-controller MO is returned to its off-position, the car or train, being now running at some considerable speed, the master,- controller will energize the train-line wire 3, which may be described as the brakeewire 3, be.-

cause it is used to set up thedynamic-braking circuits for the motors during the coasting operation. When the braking-prctective relay BP is used, shown, the brakeewire 3 is also used,.,to directly energize a hold-coil BP-Hold of the brake ing-protective relay BP, and this hold-coil may be hold the relay actuated or closed, once it has been actuate As set forth in the previously mentionedapplication Burlthart and myself, the BP-l-Iold coil is also provided with a,secondenergizingcircuit, which is independent oi the brake-wire 3, and

Cal

thus-operative in any of the three on-positions of the master-controller MC. This second hold-coil energizing-circuit includes a make-contact 259 of this brake-protective relay BP, and this makecontact 259' is used to energize the brake-wire 3 from the previously described control-circuit 20, which is under the control of the line-relay LR, so that the control-circuit i2ii is energized whenever, there is afailure of the, line-voltage, at a time. when the train-line wire 52' is energized, that is, at a time when the master-controller is on any one of its three on-positions, as previously described. In this way, I not only maintain the e-nergization of the BP-Hold coil under. theno-voltage conditions just described, thus making sure that the brake-protective relay remains in its actuated condition, but I also immediately energize the brake-line 3, without waiting for the master-controller MC to be returned. to. itsoff-position, which establishes the coasting braking-circuit connections, as will now be described.

The brake-wire 3is connected, through an LSI back-contact 269 and a BP make-contact 26!, to a control-circuit 313. This control-circuit 3IB isconnected, through a GI back-contact 262, to the previously described control-circuit wire 3!, which energizes the previously described parallelmotoring switches M and G through the JR backcontact 25! and the control-wire G6. The controlrconductor (HE is also connected, through a G! back-contact 253,1:0 a control-wire BIG, and thence to the positive terminal of the brakingswitch coilBl, the negative terminal of which is connected in a circuit which includes a B5 back-contact 265, a conductor I92, another B5 hack-contact 2'65, a conductor I04, and a JR heroin-contact 2'57, and thence to the grounded negative battery-terminal The closure of the switches M, G and BI completes the establishment of a weak coasting-operation dynamicoraking circuit-connection for the traction-motors, with all of the available dynamic-braking resistances R5, R2 and R3 in circuit, this dynamic-braking resistance being large enough so that the braking tractive-effort is usually quite wealr, at moderate motor-speeds, thus permitting the train to coast, with litle or no sensible or perceptible braking-effect, as long as the field-controller FC remains in its short-field position.

A connection is also provided, for controlling the field-controller FC during the coasting-operation. In accordance with a known practice, I provide a circuit extending from the controlwire 316, through a back-contact 258 of a brakerelay BR, to a control-circuit 32, and thence through the back-contact 269 of a spotting-relay SE, to the full-field. wire 33 of the field-controller FC. The brake-relay BR. was shown and described in a Riley-Purifoy Patent 2,523,143, granted September 19, 1950. The spotting relay SR is a previously used relay, having an operating-coil SR which is included in the common brake-circuit connection I98, so that this relay responsive to the braking-circuit current. This spotting-relay SR is adjusted to have a low-current pickup-value, so that it can hold the braking-circuit current to a small value suitable for spotting purposes, during the coasting operation of the traction-motors, as is well understood in the art.

The full-field wire 33 of the field-controller FC energizes a full-field coil FC-FF, or other means for causing the field controller FC to move or progress from, its short-field position SF to its ,i ii full-field position FF. This enerfiization of the full-field coil FC-FF under the control of the spotting relay SR thus progressively adjusts the field-controlling means FC toward its full-field position, as spotting-conditions may require.

In accordance with a known control-method, the spotting-relay SR has a make-contact 210 which connects the circuit 32 to a circuit 36, which goes to a field-controller contact-segment 21!, which is closed only during certain early points in the progressive movement of the fieldcontroller FC from its full-field position FF toward its short-field position SF. This field-com troller segment 21! is preferably opened at a certain point near the short-field-position SF, preferably before the field-controller reaches this short-field position SF. As shown, I prefer to have this field-controller segment 2''! closed at the positions FF through F3 of the field-controller FC. This field-controller segment 2'" is used to connect the wire 36 to the shortfield wire 39 of the field-controller FC. In this way, when the spotting current is too large, that is, large enough to pick up the spotting-relay SR, the spotting current is reduced by adjusting the motor-fields toward a weaker condition, by making the field-controller FC progress in the direction towards its short-field position, but this progression is usually arrested before the fieldcontroller returns all of the way back to its original short-field position SF, which it occupied before the spotting-control commenced to operate.

A service braking-application is made by the closure of the brake-lever 202, which energizes the full-brake wire from the brake-wire 3. This full-brake wire 5 is connected directly to the coil BR of the brake-relay BR. The brake-relay BR has a make-contact 272, which connects the fullbrake line 5 to the conductor 35 which leads up to the limit-relay progression-circuit 4'5, thus putting the braking progression under the control of the back-contact I99 of the limit-relay or current-relay CR, as well as under the control of the BP make-contact 238, both of which are in circuit between the conductor c5 and the limit-relay progression-circuit 46. At the same time, the opening of the back-contact 268 of the now-actuated brake-relay BR takes the braking progression out of the control of the spotting relay SR.

Whenever a braking-application is called for, the energization of the brake-relay BR closes a BR make contact 213, which is used in the initiation of the dynamic-braking progression. Thus, the BR make-contact 273 is used to make a connection from the limit-relay progression-circuit 46 to the full-field wire 33 of the field-controller PC. This causes a progression of the field-controller FC until it reaches its full-field position FF, under the control of the limit-relay CR.

The closure of the brake-relay BR also closes a make-contact 214 which makes a connection from the control-wire 3 IC to a braking-operation hold-wire H, in readiness for use in the subsequent brake-progression operations. When the braking-controlling progression has proceeded to the point at which full-field conditions are restored in the traction-motors, the field controller FC closes a full-field contactmember 216, which closes a circuit from the fullfield wire 33 to a conductor 49, and thence through a BR make-contact 211 to a brakingprogression circuit 48.

The energization of the braking-circuit progression-wire 48 immediately serves, through a Bl make-contact 218, which is already closed, to energize a circuit 12, which is connected, through a B2 back-contact 219, to a circuit 82 which is connected to the positive terminal of the B2 actuating-coil, the negative terminal of which is connected to the previously described conductor 192. The B2 switch thus picks up and closes its main contact B2 which shorts out a part of the braking-resistance R5 in the common dynamicbraking circuit Hit of the traction-motors. The actuation of the B2 switch also closes a makecontact 280 which establishes a holding-circuit for the wire 82 from the hold-wire H.

A circuit is next established from the lower end of the progression-wire 48, through a B6 back-contact 28E, to a conductor 15, and thence through a B2 maize-contact 282, which has just been closed, to a conductor 85 which is connected to the positive terminal of the B5 actuating-coil, the negative terminal of which is connected to the previously mentioned wire Hi l. The B5 switch closes its main-circuit contact B5, which shorts out more of the braking-resistance R5 in the common dynamic-braking circuit 93 of the traction-motors. At the same time, the B5 switch closes a make-contact 233 which establishes a holding-circuit from the conductor 85 back to the hold-wire H.

The energization of the braking-progression switch B5 opens its previously mentioned backcontacts 265 and 265, thus dropping out the switches Bi and B2, the main contacts of which are both short-circuited, now, by the main contact B5. The dropping-out of the Bi switch closes its lowermost back-contact 285, which completes a circuit from the conductor 15 to a B5 make-contact 285, and thence to a wire 86, which is connected to the positive terminal of the B6 coil, the negative terminal of which is connected to the wire NM. The B6 switch thus closes, and closes its main contact B6 which further shorts out some of the braking-resistor R5, thus still further reducing the efiective brakingresistance in the dynamic-braking circuits. At

'. the same time, the actuation of the B6 switch closes its make-contact 286, which establishes a holding-circuit for the wire 86 from the wire H.

The actuation of the B6 switch also closes a make-contact 287, which connects the progression-wire 48 to the previously described conductor 12, thereby reenergizing the B2 switch, the negative circuit of which is now completed from the wire m2, through a B6 make-contact 288, to the wire HM.

It will be understood that all of these brakingprogression operations are under the control of the limit-relay progression-circuit 45, which interrupts the progression whenever an excessive motor-current causes an opening of the current-relay back-contact i953, which is connected in the energizing circuit for said wire 46, thus interrupting the progression until the motorcurrent subsides to a desirable value.

The braking-circuit progression-wire 48 is also connected, through a G! out-contact or back-contact 2%, to the accelerating-resistance progression-wire M.

After the second closure or actuation of the B2 switch, so that the B2 and B5 switches are now both closed, a circuit is made, from the accelerating-resistance progression-wire 41, through a B2 make-contact 290 and a B6 makecontact 2!, to the previously described conductor 50, thus re-initiating the progression of thaswitchesl-2,, 34-4, and: 9-40, which pro:-- ressiviely I close the accelerating resistor switches.

SI, to Sit, thereby cutting out the accelerating resistors R2 and R3 which are in the individual portions of the respective dynaniic-braking circuitsofthe traction-motors, this progression being;also underthe-saine limit-relay control.

Ever since the actuation. of the B5 switch, a B5; make-contact 2221 has been energizing the accelerating-resistance hold circuit '15? from the braking-operation,hold-wire."H, in readiness for this progression. of the accelerating-resistor switchesrsl to S10. Thebraking-progression thus continues until: substantially all of the brakingresistance. isremoved from the dynamic-braking circuit,.th1ts resulting in the oonipletionoithe dynamic-braking operation, during which: train has been reduced.

the speed; of the: car or from the initial speed which the dynamic hrakewas applied, down to a low speed at which the; dynamic brake fades out.

If, a braking-operation is to be discontinued, after once having been started; the braking circuit switches are released by an opening of brakerhandle 2622, without requiring the establishment of a (perhaps momentary) power-sir cult (or lVl'C ell-position), in order to deener the-braking hold-wire ii. This is accomplishw by the BR-contact 2H, which is in series with the hold-wire. 'll.. Theopening of the brake handle ZDZ'deenergiZes the brake-relay 13R opens itscontact 2%, without requiring an onposition of the master controller MC to release thebrake-wirej, in order to deenergise theconduotor 3iC and hencethe hold-wire ll.

It has long been customary to antoniaticah 1y adjust the calibration or setting of limitrelay CR, in.order. to cause, this relay to drop out, in responsetovarious, accurately controlled desirable minimum motor-current values, during bothv the acceleration-pregression the dynamic-braking progression. This is conven iently done by various controls for the energization of the rate-coil RC of the limit-relay CR. In the drawing, I have shown two known circuits for the. rate-coil control or calibration. Cne

such rate-coil circuit involves the weight-re sponsive rheostat 2.90, and is traceable from the positive.controlepower line through an LS2 make-contact 2513, the aforesaid weight-respon sive rheostat 2%, a resistance 2%, a conductor 92,.aresistance 29,5, andthe rate-coil wire 95. A, second old. or known rate-coil energizing circuit, involves the braking-responsive resistance 2t], and is, traceable from the positive bus through a BR maize-contact 296, and the.

aforesaid brakingqesponsive rheostat 2M to the conductor 92.

As, described" in, the companion-applioation of.

6, which controlsthe switching-operation of the traction-motors, to the train-line wire 4, W1 ch controls the progressive series-motor runniu connections; I

The operation of the simplified. illustrated. ap 7 paratus willibe clear-from the-{running comments which; have-,been. made during theprogress or the description, as well as. from the prior. art..

A. few. wordsof added explanation, as tothe features which are more particularly related to mynovel controlrcircuit parts, may, however, be helpful.

In accordance with. my. present invention, I. havein efiect nullified the switching-connection.

and the scries-motor connection of the traction motors, whenever the shuntedefield connections I. prevent the, rough-brake conditions which have sometimes; been encountered as a result of the motormans.

are established. In this way,

misuse of his master-controller MC. Sometimes, when thecar or train is running at high.

speed, with the motors in their short-field con.-

then immediately again moves the master controller MC to its switching-position, or No. 1. position, which is not a running-position, and.

not intended to be used except for slow-speed operations while the car or train is being switched;

from track to track.

Nevertheless, motormen sometimes leavev the. master-controller MC in this switching-position.

while the car or train isrunning at a high speed, and-while the motorman is makingv up his mind whether he wants to resume full running condi: tions, with a iull-power applicatiomor whether he is going to have to initiate a dynamic-braking. operation. Meanwhile, in previous motor-control systems the traction-motors are connected across the power-supply line in their series motor-connections, and the motor fields are very weak;

If, now, the motorman should go into a dy-- namicbraking operation, with the motor-fields in an, excessively weakened condition for. that particular. motor-speed, then the dynamic-braking operation would start with the motors having.

a. very low field-flux. This low-flux. condition would be doubly. aggravated, not only on account. of.the presence of the field-shunts XIRS| and. X2-RS2, which divertv a considerable part of.

whatlittle motor-current there, has been, im-.-

mediately prior to. the establishmentof thedymanna-braking connections, but the motoring-' currents themselves had beenexcessively small, because. the. motorman had beenerroneously op erating, at.a.high speed, on his. No.,1. switchingposition, which means thatall of the accelerating resistances RLRZ, R3v and. R4 had been in,

themotor-cirouits, so that very little motor-currentcouldbefiowing, that is,.prior to our intro.-

duction of the new. neldecontroller contactrseg:

rcent Thus, when. dynamicebraking connections are established, while. the. motor-flux was, so extremely weak, and-remembering that themotors.

have aiather slow time-constant, so that their motor-flux cannot be built up anything like as. rapidly as the progressionnate during the build up. of. dynamimbraking conditions, thenthe dynamic braking,currents will at firstbe extreme- 1y low, causing the dynamic-braking progression to proceed. at its maximum rate, without intere ruption by thepiclzing-up of. the limit relay CR,, sov that, when the motor-flux finally builds up.

to its. increased valuatoo muchresistance will have beencutout of the dynamic-braking cir cults. and. excessive dynamimbrakingcurrents will bezobtained'.

I avoid these difiiculties by, in effect, preventing the motorman from operating a fast-moving car or train with the traction-motors connected in either their switching-connections or their series motor-connections. Whenever the acceleration-progression of the traction-motor control has advanced far enough to cause the fieldcontroller FC to adjust itself to any of its positions F3 to SF, if the motorman should then move his master-controller MC to its off-position, and should then immediately notch it up again to its No. 1 switching-position, while the train is still running fast, the field-controller contact 306 will connect the switching-controlling wire 6 to the wire 4, and my new field-controller contact 253 will continue this connection on, to the parallelmotor control-wire 66, through the circuit 62l -68--25366. At the same time, my new field-controller contact 220 prevents the energization of the series-motor-connection switch JR from the circuit t2 i 560--2 I 5-62--220-63.

Consequently, neither the series-motor switching-connections nor the series-motor runningconnections are made, under these conditions, by the No. 1 switching-position of the master-controller MC; and the switching-connection trainline wire 4 is connected straight on, to the parallel-connection wire 66, which energizes the parallel-connection switches M and G, which establish the parallel motor-connections, The second line-switch LS2 is picked up through the circuit 4-2244622542, and this switch LS2 thereupon closes its contact 228 and thus energizes the progression-controlling circuit 4,224- 453-228-45-l99-430-46-23I-4!. The progress-wire d! rapidly and uninterruptedly cuts out all motor-resistance during these high-speed parallel-motor-connection operating-conditions, thus materially increasing the field-strength of the motors, even though the motorman should improperly leave his master-controller on its No.

1 switching-position while the car or train is operating so fast.

An advantage of establishing a parallel-motor connection of the traction-motors, with all of the accelerating resistance cut out, instead of permitting the motorman to operate the train on the series-motor connection, with the accelerat-' ing-resistance either in or out, while the train is running at speeds high enough to have caused the field-controller FC to have adjusted itself to.

a shortened-field position, is that the parallelmotor connection causes the motors to draw enough currentto build up the field-flux to a reasonably high value. Thus, if the motorman goes into dynamic braking from this operatingcondition, the motor-field is reasonably high,

and this permits the recapturing of a higher residual voltage, when dynamic brake is applied, then was the case in previous control-systems. 'Ifhe dynamic-braking operation therefore starts out with higher voltages generated in the traction-motors, so that the recalibrated limit relay CR; does not immediately cut out too much braking-circuit resistance in an efiort to bring up of the motor, and this results in protection against motor-flashing and rough brake-buildup.

While I have described my invention in con-- nection with a motormans manipulation of the master controller after he has attained highspeed operating conditions, the same advantages hold true in regard to the protection of the motors in passing third-rail gaps.

It will be understood, of course, that if the motorman had left his master-controller in the off-position, for even a very brief moment, before going into dynamic braking, the coasting or spotting conditions would have been established, wherein the motors would be connected in parallel, and the motor field-strengths would have been properly maintained and adjusted by the mild dynamic-braking currents which flow during coasting or spotting. The trouble came, in previous motor-control systems, when the motorman went into the maximum-resistance se-- ries-motor switching-connection while the car was running fast, and then immediately changed into the dynamic-braking connection for a brakeoperation.

While I have described my invention, and explained its manner of operation, in connection with a particular simplified illustrative form of embodiment, I wish it to be understood that the efficacy of the invention would not be affected by the addition of desired additional features or safeguards or by the omission of undesired or unnecessary features, or by the substitution of equivalent or alternative forms of various means or elements for performing the essential elementfunctions which have been described and explained.

I claim as my invention:

1. A motor-controlling assembly, including the combination, with a plurality of series motors to be controlled, each series motor including a motor-armature and a series field winding connected in series therewith, of: (a) an accelerating-controller, having an off-position and a plurality of on-positions, said on-positions including a series-motor-connection running-position, and a parallel-motor-connection running-position; (1)) a series-connection control-means, for establishing a power-circuit for energizing the series motors in a series-motor connection in response to the series-motor-connection runningposition of said accelerating-controller; (c) a parallel-connection control-means, for establishing a power-circuit for energizing the series motors in a parallel-motor connection in response to the parallel-motor-connection runningposition of said accelerating-controller; (d) a variable field-controlling means, for progressively adjusting said series field Winding toward a full-field condition and toward a short-field con-.

dition, respectively; (e) a progressively operating acceleration-controlling means, for controlling the acceleration of the series-motor means;

during each of the power-circuit operating-conditions, said acceleration-controlling means including a first-operating voltage-controlling means for controlling the voltage which is effective on the motor-armature, and a finally operating field-controlling means for causing said field-controlling means to progressively adjust said series field winding toward its short-field condition in the parallel-motor power-circuit.

connection; and (f) a shortened-field-responsive means, responsive to a shortened-field condition of said field-controlling means, and re sponsive' to all of the on-positi'on's of the accelcrating-controller, for establishing the parallelmotor power-circuit connection and nullifying all accelerating-controller on-positions other than the parallel-motor-connection running-position.

2. A motor-controlling assembly, including the combination, with a plurality of series motors to be controlled, each series motor including a motor-armature and a series field winding connected in series therewith; of (a) a supplycircuit for the series motors; (b) a power-switch means, for establishing a power-circuit for energizing the series motors, first in a seriesmotor connection, and then in a parallehmotor connection, from the supply-circuit; (c) a braking-switch means, for establishing a dynamicbraking circuit for the series motors; (d) a variable field-controlling means, for progressively adjusting said series field winding toward a fullfield condition and toward a short-field condi tion, respectively; (e) a progressively operating acceleration-controlling means, for controlling the acceleration of the series-motor means during each of the power-circuit operating conditions, said acceleration-controlling means including a first-operating voltage-controlling means for controlling the voltage which is eiiective on the motor-armatures, and a finallyoperating field-controlling means for causing said field-controlling means to progressively adjust said series field winding toward its shortfield condition in the parallel-motor powercircuit connection; (f) a progressively operating spotting-controlling means for controlling the spotting-adjustment of the dynamic-braking circuit during coasting conditions, said spottingcontrolling means including a mean for causing said field-controlling means to progressively adjust said series field winding toward its full-field condition; (y) a progressively operating brakingcontrolling means, for controlling the brakingadjustment of the dynamic-braking circuit during dynamic-braking conditions, said brakingcontrolling means including a first-operating means for causing said field-controlling means to adjust said series field winding to its full-field condition; (h) an accelerating-controller, having an off-position, a switching-position, a seriesmotor-connection running-position, and a parallel-motor-connection running-position; (2') a bralzing-controllen having an calf-position and an on-position or positions; (7') a starting-circnit means, for closing the power-switch means in a series-motor connection, while maintaining said progressively operating acceleration-controlling means in its lowest-speed condition, in response to a switching-position of the acoeleratingcontroller; (is) an accelerating-circuit means, responsive to a closed condition of t -e powerswitch means, and each of the running-positions of the accelerating-contro1ler, for causing a progressing operation of the progressively operating acceleration-controlling means; (2) a spotting-circuit means, responsive to an oiiposition of the accelerating-controll r and an off-position of the braking-controller, for closing the braking-switch means and causing a progressing operation of the spotting-controlling means; (m) a braking-circuit means, responsive to an elf-position of the accelcrating-controller and an on-position or positions of the brakingcontroller, for causing said field-controlling means to adjust said series field winding toward a fuller field; and a means, operative after fullfield conditions have been established during dynamic-braking conditions, for causing a continuing progressive operation of the progressively operating braking-controlling means; and (a) a means, responsive to a shortened-field con dition of said field-controlling means, for establishing a temporary circuit-connection between the switching-position and the parallel-motorcon ection running-position of the acceleratingcontroller.

3. The invention as defined in claim 2, characterized by said shortenedfield-responsive temporary-circuit connection-means (n) including an accelerating-circuit means for causing a progressive operation of the first-operating means of said acceleration-controlling means (e).

GEORGE R. PURIFOY.

No references cited.

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