US2262375A

US2262375A - Control mechanism

Info

Publication number: US2262375A
Application number: US239931A
Authority: US
Inventors: Walter H Smith
Original assignee: Westinghouse Electric and Manufacturing Co
Current assignee: CBS Corp
Priority date: 1938-11-12
Filing date: 1938-11-12
Publication date: 1941-11-11
Anticipated expiration: 1958-11-11

Description

Nov. 11, 1941. w. H. SMITH CONTROL MECHANISM Filed Nov. 12

aammuzatiflg Winding 'ampr'essbr D Gil/[072 INVENTOR WaZzer/i Sm 2272.

ATTORNEY Patented Nov. 11,1941

CONTROL MECHANISM Walter H. Smith, Wilkinsburg, Pa., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application November 12, 1938, Serial No. 239,931

14 Claims.

My invention relates to control mechanism and it has particular relation to reverse-directionresponsive controlling mechanism associated with a direct-current dynamo-electric machine and a storage battery on a railroad-car or other transportation-device. More specifically, my invention vielates to apparatus for conditioning the air in passenger vehicles or for cooling commodities in other vehicles, particularly vehicles of the railroad type, although my invention is not .limited to such uses.

One object of my invention relates to the provision of a so-called drag-relay characterized by having two pairs of contact-members, for each direction of movement, the contact-members of each pair being actuatable in responsive to different amounts of displacement of the drag-relay.

A further object of my invention relates to the provision of a distance-responsive relay comprising a pair of cam-actuated pivoted arms, with suitable means for holding and releasing the arms. I

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

combinations and apparatus hereinafter described and claimed, and illustrated in the accmpanying drawing, in which the single figure is a diagrammatic view of circuits and apparatus embcdying my invention and illustrating the principles thereof.

The drawing shows my control mechanism in a form adapted for application to a railroad car having a car-axle I which is provided with a gear-drive 2 for driving an axle-driven shaft 3.

The illustrated mechanism is utilized in connecswitch H, to positive and negative buses and i The equipment further includes a direct-curlent dynamo-electric machine l2 which is use- 'ab e either as a generator for charging the battery ill, or as a battery-energized motor for driving the compressor 4 through a mechanical driving- I, when the unloaderconnection, such as the belts II. The electric machine I2 is provided with a field-winding l4 and a commutating winding IS, the latter being connected in series with the armature-circuit I6, one terminal of which is permanently connected to the negative battery-terminal and the other terminal of which is controlled in accordance, with my invention.

The illustrated equipment further includes a speed-responsive, engageable and disengageable,

mechanical driving-means, illustrated in the form of a centrifugal clutch IT, for mechanically connecting the axle-driven shaft 3 to the compressor 4 and to the electric machine 12 at car-speeds above a predetermined speed, such as 12 miles per hour, and for disconnecting the same at lower speeds.

In accordance with my invention, I provide a so-called drag-relay l8, and a so-called distancerelay I9, both of which are controlled, for convenience in installation, from an auxiliary shaft 2| which is mechanically connected, through a belt-drive 22, to the axle-driven shaft 3. Both the drag-relay l8 .and the distance-relay [9 are of special construction, which will now be described.

The drag-relay l8 acts as a reversing-switch means for responding to movement of the caraxle l, and it comprises a reversibly movable disc or other switching member 23, having biasing means, in the form of two sets of

springs

24 and 25, for restoring the disc 23 to a neutral central position. The

biasing springs

24 and 25 are pro vided, as illustrated, with means, such as stops 26, for increasing the effectiveness of the springs at a predetermined displacement ofthe disc 23 from its neutral position, in order to provide a first tilting-range in which the disc 23 is easily tiltable, in either direction, and a second tiltin.,- range in which it is necessary to exert a larger tilting-force per unit displacement of the disc 23.

The tiltable disc 23 of the drag-relay l8 carries four inclined mercury-

switches

21, 28, 29 and 30, or equivalent tilt-responsive contactmechanisms. These four mercury-switches '21 to are arranged in pairs,one

pair

21 and 28 being actuatable in response to forward movement of the car-axle I, and the other pair 29 and 20 being actuatable in response to backward movement of the car-axle I. The

first mercuryswitches

21 and 29 of the respective-pairs are just slightly tilted, and thus they are arranged to be sensitively responsive to very slight displacements or tiltings of the switch-carrying disc 23,

and they are so arranged that their electrical con 'tacts are broken when said mercury-

switches

21 and 29 are actuated in response to the tilting of the disc 23. The second mercury-switches 28 and magnet 33 is carried by the auxiliary shaft 2|,

while the drag-disc 32 is carried by a shaft 34 which is connected to the tilting disc 23. When torque is applied to the magnet 33, a very slight movement of the magnet with respect to its associated drag-disc 32 causes suflicient eddy currents in the drag-disc to establish a sensible torque in the shaft 34, tending to tilt the switch-carrying disc 23 in the same direction of rotation as the magnet 33. As the slip between the magnet 33 and the drag-disc 32 increases, the electrical torque also increases, up to a point determined by the design of the apparatus.

My distance-relay |9 is designed to detect movement in the auxiliary shaft 2| which, in turn, moves with the car-axle I, and it comprises a pair of arms 36 and 31, pivoted at 38 and 39, normally drawn towards each other by means of a spring 4|, and actuatable away from each other by means of a cam 42 carried by the auxiliary shaft 2|. Each of the pivoted arms 36 and 31 carries two front or make

contacts

43 and 44, and one back-contact 45, the make-contacts being closed whenthe respective arms are actuated, and the back-contacts being closed when the respective arms are in their normal non-actuated positions. The respective arms 36 and 31 are also provided with arm-holding means, illustrated in the form of magnet-coils 46, which are capable of retaining their respective arms in their actuated positions.

Associated with the steeply tilted

mercuryswitches

28 and 38 of the drag-relay I8, is a reversing relay 48 of a well known type, which is provided with a forward electromagnetic switching element 49 and a backward electromagnetic switching element 58, the two switching elements being mechanically connected together by means of a tilting lever 5|, so that when one of the switching elements is closed, the other is open. The operating coil of the forward" switching element 49 is energized by the closure of the forward mercury-switch 28, while the operating coil of the backward switching element 58 is energized when the backward mercury-switch 38 is actuated to close its contacts. I

The reversing-switch elements 49 and 58 are each provided with a first make-contact 53 which serves to connect a control-circuit bus 54 to the positive battery-terminal when either one of the steeply tilted mercury-

switches

28 or 38 is actuated to its closed position.

Each oi the reversing-switch elements 49 and 58 is also provided with a second make-contact 55 for connecting the negative battery-terminal to either terminal 56 or 51 of the field-winding'l4, depending upon the position of the reversing-switch mechanism 48. Each of the reversing-switch elements 49 and 58 is also provided the reversing-switch mechanism 48.

The auxiliary switching bus 54 serves, among other things, to energize the operating coil or a so-called field-transfer switch 6|, which is provided with a back-contact 62 and a front or make-contact 63. Thus, when the auxiliary relaying bus 54 and the field-transfer relay 6| are deenergized, that is, when the steeply tilted mercury-

switches

28 and 38 are in their non-actuated positions, the back-contact 62 of the field-transfer relay 6| is closed, so as to partially make a motoring" field-energizing circuit which may be traced, for the present, from a conductor 54, through the back-contact 62, to two serially connected resistors 65 and 68, and thence to the fieldenergizing circuit 59. When the field-transfer switch 6| is energized, however, as a result of the actuation of either one of the mercury-

switches

28 or 38, the motoring field-circuit is broken at the back-contact 62, while the make-contact 63 of the relay is closed, thus energizing a generating field-circuit extending from the positive battery-terminal through a carbon-pile rheostatic voltage-regulator .61, and the makecontact 63, and thence to the field-energizing circuit 59.

The auxiliary control-circuit 54, which is energized from the positive bus wheneither one of the steeply tilted mercury-

switches

28 or 38 is actuated, is also utilized in the control of the generating operation of the electric machine l2, and for this purpose, it is connected in series with the usual generating contact I8 of a reverse-current relay II, which may be of usual construction, and which is illustrated as having a polarizing winding 12 energized from the storagebattery terminals and and two actuating windings I3 and 14. The actuating winding '13 is a current-winding which is illustrated as being connected across a shunt I5 in the armature-circuit 6 of the dynamo-electric machine l2. The other actuating winding 14 is a voltagewinding which is connected so as to be responsive to the voltage-difierence between the battery 8 and the armature-circuit |6 of the dynamo-electric machine 2, as will be subsequently described. In accordance with my invention, the reverse-current relay 1| is provided with an extra back-contact 18, which is not usually provided on such relays, but which I utilize as an extra safeguard in controlling the motoring operation of the electric machine l2, as will be subsequently described.

The first-mentioned make-contact ll of the reverse-current relay 1|, is utilizedto connect the auxiliary switching bus '54 to a starting-bus 88 which is utilized for starting the dynamo-electric machine |2 in a mannerwhichwill be subsequently described. The starting circuit which traces back from the starting bus 88, through the reverse-current relay-contact l8, and the auxiliary switching bus 54, to'one or the other of the steeply tilted mercury-

switches

28 and 38, is utilized in controlling the operation of the dynamo,- electric machine l2 as a generator.

I also provide means for controlling the start 'ing circuit 88 during the operation-of the dynaand this which starts to the left of the 'drag-relay-l8, at

the positive battery-terminal and thence passes through a thermostatic switch 8| to an auxiliary motoring circuit 82. The thermostatic switch 8| is utilized to close its contacts when it is desirable to operate the compressor 4 to produce more cooling. and to open its contacts when no more cooling is needed. The motoring circuit 82 is connected in series with the two back-contacts 45 of the distance-relay I8, and thence to an auxiliary motoring circuit 88. The two backcontacts 45 of the distance-relay I8 are connected in parallel with each other, so that the auxiliary motoring circuit 83 is energized whenever either one of the back-contacts 45 is closed, that is, whenever either one of the pivoted arms 38 and 81 is in its normal non-actuated position, provided, 01' course, that the thermostatic switchcontacts 8| are closed.

It is necessary, now to describe the connections of the distance-switch I8, whereby the opening and closing of the back-contacts 45 are controlled. Each of the holding-magnets 48, for holding the respective arms 88 and 81 in their actuated positions, is connected, through its associated front-contact 44, in an energizing circuit including a normally'closed contact 84 of a thermal relay 85. The thermal relay 85 is provided with a heater-element 88 which is enerafter the tiltable switch-carrying disc 28 of the drag-relay returns to its normal neutral position, as the railroad-car approaches its condition of standstill after having been moving in either direction.

Picking up the thread of the motoring circuit which has been traced from the positive battery- 'terminal through the thermostatic switch 8|, the motoring circuit 82, and the distancerelay back-contacts 45, to the auxiliary motoring circuit 88, it will be noted that this auxiliary motoring circuit 88 is next connected in series with a make-contact 88 of a low-voltage cut-out relay 88, and thence through the "motoring" back-contacts 18 of the reverse-current relay II,

to the previously-mentioned starting" circuit 88. The low-voltage cut-out relay 88 will be subsequently described.

The "starting" circuit 88, when energized either through the generating" circuit starting with one or the other of the steeply tilted

mercuryswitches

28 or 88, or through the "motoring" circuit starting with the thermostatic switch 8|, is utilized to energize a train of relays 8|, 82, 83 and 84, which together constitute the starting mechanism for my dynamo-electric machine l2. The first relay 8| of this train is first energized from the starting circuit 88, through a backcontact 85 of the third relay 88. The first relay 8| thereuponinstantly picks up and closes its make-contact 88 which instantly energizes the second relay 82, causing the latter to instantly pick-up and close its make-contacts 81 and 88, which instantly energize the third and

fourth relays

88 and 84, respectively. The actuation of the third relay 88 closes its make-contact I88,

Ill

which 'energizes the main armature-circuit l8 of the dynamo-electric machine I2 by connecting the same in a circuit which is traced from the positive battery-terminal through the starting relay-contact I88, thence through the shunt I5, and thence through a starting resistor I 8|, to the current-coil I82 of the rheostatic regulator 81, and thence through the commutating winding I5 to the armature oi the dynamo-electric machine, the other terminal oi which ispermanently connected to the negative bus The first, second and fourth starting relays 8|, 82 and 84 are of a type having an instantaneous pick-up and a slow drop-out of, say, two seconds, as is symbolized by the dashpots I84. The third starting relay 88 is the main line-contactor, having the main line-switch III as previously described, and it locks'itsel! in, as indicated, through a holding-circuit make-contact I85, so that it thereafter stays "in as long as the "starting" circuit 88 is energized, regardless of the position of the second starting relay 92.

The first and fourth starting relays 8| and 84 are provided with make-contacts I88 and I81, respectively, which are utilized to short-circuit the motoring" field-

resistors

88 and 88, respectively. The second starting relay 82 has a backcontact I88 which is utilized to short-circuit the armature-circuit starting-resistor I 8 I As soon as the main line-contactor 88 picks up, it opens its back-contact 88 and deenergizes the first starting-relay 8| causing the latter to start to drop out in a time, such as two seconds, determined by its dashpot I84. When the first starting-relay 8| completes its drop-out movement, it opens its make-contacts I 88 and 88, thereby inserting the field-resistance 88 in the motoring" field-circuit, and deenergizing the second starting relay 82, causing the latter to start to drop out. in a time, such as two seconds, determined by its dashpot I84. When the second starting-relay 82 completes its drop-out motion,

it closes its back-contact I88 and opens its frontcontact 88, thus cutting out the armature-circuit starting-resistance IM and deenergizing the fourth starting relay 84, causing the latter to start to drop out in a time, such as two seconds, controlled by its dashpot I 84. When the fourth starting relay 84 completes its drop-out movement, it opens its make-contact I81 and thereby inserts the field resistor 88 in the "motoring" field-circuit.

The voltage-coil 14 of the reverse-current relay II is connected across the main contact I88 of the main line-switch 82. I

The carbon-pile voltage-regulator 81 which is utilized in the generating" field-circuit is provided with a voltage-winding 8 which is responsive to the voltage of the dynamo-electric I machine I2,

The unloader relay 8 which is associated with the compressor 4, is energized from the motoring circuit 82, which is energized whenever the thermostatic switch 8| is closed, calling for more cooling.

The low-voltage cut-out relay 88 compriseses- ..sentially a voltage-coil I I2 which is normally connected in shunt across the battery terminals and through a resistor I I3 and a makecontact I on the main l-ine-contactor 88 of the "starting mechanism. Thi low-voltage relay 88 also normally holds itself ,in through its own make-contact 8 which bypasses the make-contact N4 of the starting-relay 88. The function I of the battery as a result of prolonged operation of the compressor 4 from the battery, the low-voltage cut-out relay 89 being provided in order to make sure that enough battery-capacity will always be left to take care of lighting, ventilating, and other necessary requirements.

In order to prevent the low-voltage cut-outrelay 89 from dropping out, on the momentary dip in voltage resulting from the large currentinrush when starting the electric machine I2 as a motor, a weak series coil H8 is provided on the same magnetic circuit as the voltage-coil H2, and energized from the current-shunt I5, in such direction and amount, as to give the voltagecoil II2 a sufficient boost during the startingcurrent inrush when the motoring operation is first initiated.

In order to be able to start the compressor 4 when the car is, standing in a switching yard, after a period of non-use with the main batteryswitch I'I open, I have provided, in association with the resistor II3 of the cut-out relay 89, a

starting push-button II8, which may be depressed, to pick up the cut-out relay 89, after the main battery-switch 'II has been closed, if the battery-voltage is over 70% of its normal strength. The push-button H8 is preferably arranged to momentarily energize the cut-out relay 89' through only a portion of its series resistance II3. After the cut-out relay 89 has once picked up, it will seal itself in, through its make-contact I I5, and its operating coil I I2 will receive enough current, through all of the resistance II3, to

- hold the relay in its closed position.

The operation of the mechanism is as follows. Referring to the generating operation of the electric machine I2, when the car starts into operation and attains a suitable speed for operating the compressor 4, such speed being perhaps of the order of 12 miles per hour, the centrifugal thus setting up the field-reversing relay 48 in 1 the proper polarity depending upon the direction of car-travel. For convenience in visual-, izing the phenomena, it may be assumed that the mercury-

switch

28 or 38 closes when the car attains a speed of 12 miles per hour, the same as the operating speed for the centrifugal clutch II, although these two operating speeds need not be identical with each other. When the me!- cury-

switch

28 or 38 closes, it also energizes the field-transfer relay 8|, thus braking the "motoring field circuit at 82 and establishing a generating" field circuit at 83, with maximun'figencrating" field-strength in the field circuit.

When the car attains a speed, such as 25 miles per hour, at which' the generator-voltage is slightly in excess of the battery-voltage, the reverse-current relay-contact I8 closes, under the influence of its voltage-coil I4, thus instantly energizing the starting relays 9| to 94, so that the main line-contactor starting-relay 93 will pick up and close its main-contact I88, completing thearmature-circuit I8 of the generator, and causing the generator to thereupon charge the storage battery I8. The reverse-current relay II then holds itself closed under the influence of its current-coil I3. It will be noted that the armature-resistance I8I is in circuit with the generator for a very brief .time, until the second starting-relay 92 drops out and closes its backcontact I88. When the car-speed drops back to a'value below which the generator can no longer charge the battery I8, the reverse-current relay II drops out, opening its contact I8, thus deenergizing the main line-contactor 93, and opening the generator armature-circuit I8 at I88.

When the car is standing still, the dynamoelectric machine I2 is operable as a motor, driving the compressor 4 from the storage battery I8, under the control of the thermostatic switch 8|. It will be remembered that the centrifugal clutch II is open, under these conditions, so that the mechanical driving-connection I3, which exit is impossible for the cam 42 to be actuating,

or pushing out, both of the pivoted arms 38 and 31. Hence, at standstill, at least one of the pivoted arms 38 or 31 is bound to be in its normal non-actuated position, as controlled by the biasing spring 4|, and it is possible that both of the pivoted arms 38 and 3.1 may be in their normal non-actuated positions, as illustrated.

Under the circumstances just described, the

auxiliary motoring circuit 83 is energized, through one or both of the distance-relay contacts 45, and through the motoring circuit 82 which is under the direct control of the thermostatic switch 8I. Since the low-voltage cut-out relay 89 is normally energized, its contact, 88, in the motoring control circuit, is closed. Since the reverse-current switch II is in its deenergized position, its "motoring contact I8 is also closed. An energizing circuit is thus completed from the auxiliary motoring circuit 83, through the contacts 88 and I8, to the starting control-circuit bus 88, which serves to start the motor by energizing (by way of relays 9| and 92) the main line-contactor 93, and completing the motoring circuit at the contact I88, thus connecting the motor armature-circuit I8 across the storage battery I8, in series with the starting armatureresistance |8|.-

The motor starts, with full motoring fieldstrength, through a portion of the motor-armature circuit I8, starting with the positive battery-terminal at the main line-contactor relay-contact I 88, and continuing on through the shunt I5 to the field-circuit,,conductor 84, and thence through the normally closed backcontact 82 of th field-transfer relay 8|, and thence through the starting-relay contacts I88 and I8! which short-circuit the field-resistors and 88.v The field-circuit thereupon continues, through the conductor 59, andthrough assasvs at one of the relay-contacts ll of the field reversing relay 44.

'Ihe motor l2 thus starts up, driving the compress? 4. At two-second intervals after the initial energisation of the motor. the first, second and fourth starting switches ll, 02 and 44 drop out, thereby' first cutting in the fieldresistor ll, second cutting out the armatureresistor ill, and third cutting in the fieldresistor 04, which places the field-circuit in its normal motoring condition.

The motor continues to operate, until the starting" circuit 44 is interrupted, as at one of the contacts 4|, 4| and I4.

When the car starts to move, the cam 42 of the distance-relay it immediately starts to move with the car-axle I. The arm-holding magnets 4| of the distance-relay ll are ready to be energiaed as soon as their respective associated make-contacts 44 are closed, the magnet-energizing circuit being completed through the normally closed back-contacts l4 of the thermal time-delay relay II. The initial movement of the cam 42 thus results in actuating first-one and then the other of the two pivoted arms II and 21, and each arm, as it reaches its actuated position, energizes its associated holding-magnet 48 and holds itself in its actuated position. so that the cam 42 will no longer strike that arm, as the cam continues to rotate. It will thus be evident that, before the cam 42 has'made a com.- plete rotation, both of the pivoted arms ll and 81 will be locked in their actuated positions, with their back-contacts 45 open, so that the motoring control-circuit is opened at 45, even though the thermostatic switch ll is closed, still calling for more cooling. It will be noted that this response of the distance-relay If, in opening the motoring control-circuit at 4|, will be made, at the earliest possible moment, in response to an extremely short distance of travel, and vregardless of the speed of the car, which will be negligible at this point.

At the time when the back-contacts 45 of the distance-relay [9 open, the car may not have moved sufficiently to open either one of the slightly tilted mercury-

switches

21 and 29 of the drag-relay disc 22, so that, if the thermostatic switch ll still has its contacts closed, calling for cooling, a circuit will be completed from the positive battery-terminal through the thermostatic switch II, the mercury-

switches

29 and 21, the two front-contacts 42 of the distancerelay is, and the heating-element I! of the thermal time-delay relay 85, as soon as both of the pivoted arms 26 and 31 are moved to their actuated pomtions. If this energization of the thermal time-delay relay I! should continue for the time-delay relay II to continue to be energized for anything approaching ten seconds, unless the railroad car immediately stops after the very slight motion necessary to open 'both contactsbecause the slightly-tilted mercury-switch 21 or 2!, depending upon the direction of rotation,

is very sensitive in its response, and will respond moving to its actuated position, opening its,

the car continues to sensibly move, very slow speed less than half of a per hour, after having moved far enough to open both back-contacts 44. As soon as one of the mercury-switches 21 or 20 opens, it deenergises the thermal relay 44, thus preventing an opening of the thermal-relay contact 84, so that the arm-holding magnets 40 continue to remain energised, holding the pivoted arms It and 21 out of contact withthe cam 42, as the latter continues to rotate with the rotation of the caraxle I.

As the car continues to accelerate, it will finally reach-the speed, such as 12 miles per hour, at which the centrifugal clutch I! will engage, thus driving the compressor 4, and if the thermostatic switch Ii is still closed, calling for more cooling, the unloader relay I will be energized, thus causing the unloader-valve I to be in a closed position, shutting on the direct communication between the discharge-pipe U and the suction-pipe i of the compressor, so that the compressor will be loaded, performing the function of driving the refrigerant through the refrkerating equipment (not shown) which is connectedtothepipeslandtinamanner' which is readily understood.

If, while the centrifugal clutch i! is engaged, the thermostatic switch OI should open its contacts, signifying that no more cooling is needed, the unloader-relay 4 will be deenergized, causing the unloader-valve I to return to its normal open position, so that the refrigerant freely circulates through the valv 1, without sensible load upon the compressor 4, instead of passing through the refrigerating equipment as in the normal operation of the compressor.

When the speed of the car again drops below the operating point of the centrifugal switch l1, which may be something of the order of 12 miles per hour, the compressor 4 is again disengaged from the car-axle I, so that it becomes. for the time being, impossible for the compressor 4 to be driven, so as to obtain cooling, even though the thermostatic switch II is closed, demanding more cooling.

When the car-speed reaches a very low value, which may be considerably less than one-half of a mile per hour, the drag-magnet disc 23 returns to its normal neutral position, so that both of the slightly tilted mercury-

switches

21 and 29 are closed. A circuit will then be completed, assuming that the thermostatic switch 8| is still closed, through these two mercury-switches 21 and 20, and through the make-contacts 43 of the two pivoted arms 38 and I! which are both being held in their actuated positions, so that the heating element 80 of the thermal time-delay relay II becomes energized. Ina predetermined time thereafter, such as 10 seconds, depending upon the operating constants of the timing relay It, the relay-contacts 84 open, thus deenergizing both of the holding-magnets 4i, and permitting both of the pivoted arms ll and 21 to return to their normal, non-actuated position, unless one of said arms may be held open by reason of the fact that the cam 42 might have come to rest underneath said arm. The timing-switch delay of 10 seconds is designed to be so long that, even though the car was slightly moving at the point when the drag-relay switches 21 and 2! were both closed, the car will have had more thanample time to come to a complete standstill, before either one or both of the pivoted arms I! and I! are permitted to return to their normal non-actuated positions in which they will close their back-contacts ll and energize the auxiliary motoring control-circuit 08, provided that the thermostatic switch II is still calling for more ceefing The time-delay of 10 seconds. more or less, introduced by the timing-relay II, is particularly useful when the railroad-car is quickly brought to a stop, and instantly reversed, as frequently occurs when it is being driven by a switching engine. Under these circumstances, the 10- second time-delay prevents an undesired momentary starting of the electric machine I! as a motor driving the compressor 4. If the motor had been permitted to momentarily start up, driving the compressor 4 in the same direction in which the car had first been travelling, which is the function of the field-reversing switch ll, then when the car suddenly reversed its direction of travel. and very quickly accelerated in the reverse direction, it might attain a speed of 12 miles per hour, sudicient to close the centrifugal clutch I1, before the compressor 4 had had time to come to a complete stop, thus subjecting the mechanical drive-mechanism to the strain of being required to first bring the compressor to standstill before it would be possible to start it up in the reverse direction.

It will be understood, of course, that any suitable braking means may be associated with the motor I! for quickly atom) the same whenever it is electrically deenergised after a motoring operation. As such means are well known, I have not complicated my drawing by attempting to illustrate the same.

It will thus be seen that, between standstill and approximately 12 miles per hour of the rail; road-car, or whatever other speed of operation is inherent in the speed-responsive clutch II, it is While I have illustrated my invention, am explained its mode of operation, in connection with a preferred form of embodiment, I desin it to be understood that such illustration and explanation are only by way of example. as mam changes, in the way of omisions, additions, and substitutions, may be made by those skilled in the art without departing from all of the essential features of my invention. I desire, therefore, that the appended claims shall be accorded the broadest construction consistent with their language and the prior art.

I claim as my invention:

1. Mechanism for driving a mechanical load device on a movable transportation-device, comprising electrical driviug-means for driving said mechanical load device when the transportationdevice is stationary, mechanical driving-means motivated by the movement of the transportation-device for driving said mechanical load device when the transportation-device is moving, movement-responsive means responsive to a predetermnied short distance of travel from standstill, substantially regardless of speed, for insur ing a deenergisation of the electrical drivingmeans when the transportation device begins to move, and time-delayed means, operative independently of the speed of the mechanical load device, for delayedly resetting said movementresponsive means to its non-responsive position after a cessation of movement of the transportation-device.

muechanismfordrivingamechanicalload device on a movable transportation-device, comprising eleetrical driving-means for at times driving said mechanical load device, mechanical driving-means motivated by the movement of the transportation-device for at times driving said impossible to obtain cooling, by means of the compressor I. This is not a disadvantage, however, because passenger cars, and in general, other transportation-devices, do not operate, for any material length of time, at very low speeds. Thus, passenger trains commonly accelerate and decelerate at the rate of one mile per hour per second, so that the compressor I would be out of commission, on such a train, for a maximum period of 12 seconds, which would be altogether negligible.

I have shown an alternative connection, associated with the auxiliary motoring controlcircuit N, in the form of a two-position switch iii. In the full-line position of the switch lli, the motoring" control-circuit connections are as previously indicated. with the "starting bus OI connected. through the relay-contacts II and 80, to the auxiliary motoring circuit 08, and thence through either'back-contact ll of thedistance-relay II, to the thermostatic switch Ii. If this two-position switch iii is moved to its dotted-line position, the "starting circuit I. is connected, through the relay-contacts It and II and the switch ill, to an auxiliary circuit III, which is energized through the two slightly tilted mercury-switches 21 and ll, and thence to the thermostatic switch Ii. Under these conditions, the starting and stopping of the motoring operation of the dynamo-electric machine I! is direct- 1y under the control of the drag-relay mercuryswitches 21 and 2!; and the distance-relay II is not utilised at all. The operation of these mercurs-switches 21 and flhasalreadybeenfully described.

mechanical load device, said electrical and mechanical driving-means being each eifectively operative only upon the fulilllment of certain predetermined conditions, speed-responsive means responsive to the speed of the transportationdevice. said speed-responsive means being operative inresponse to increasing speeds of the transportation-device for fulfilling a condition necessary to the functioning of the mechanical driving-means in response to a transportation-device speed above a predetermined value, said speedresponsive means being operative in response'to decreasing speeds of the transportation-device for insuring that the aforesaid mechanical driving-means is substantially inoperative in response to a transportation-device speed below a predetermined value, means so interrelatedto the decreasing-speed response of said speed-responsive means as to be operative only sullequently thereto in response to decreasing spade of the transportation-device for fulfilling a condition necessary to the functioning of "the electrical driving-means, movement-responsive means for insuring a deenergisatioh of the electrical driving-means when the-transportation, device barelybegins tov move-and time-delayed means, operative independently or the speeds! the mechanical load device, for rel'ayedly resetting said movement-responsive mans to its nonrespomive position after a cessation of movement of the transportation-device.

3. Mechanism for driving a mechanical load device on a movable transportation-device, comprising electrical driving-means for at times drivim said mechanical. load device, mechanical driving-means motivated by the movement of the transportation-device for at times driving said mechanical load device, said electrical and mechanical driving-means being each effectively operative only upon the fulfillment of certain predetermined conditions, speed-responsive means responsive to the speed of the transportation-device, said speed-responsive means being operative in response to increasing speeds ofthe transportation-device for fulfilling a condition necessary to the functioning of the mechanical driving-means in response to a transportationdevice speed above a predetermined value, said speed-responsive means being operative in response to decreasing speeds of the transportation-device for insuring that the aforesaid mechanical driving-means is substantially inoperative in response to a transportation-device speed below a predetermined value, means so interre-' lated to the decreasing-speed response of said speed-responsive means as to be operative only subsequently thereto in response to decreasing speeds of the transportation-device for fulfilling a condition necessary to the functioning of the electrical driving-means, movement-responsive means responsive to a predetermined short distance of travel from standstill, substantially regardless of speed, for insuring a deenergization of the electrical driving-means when the transportation-device begins to move, and time-delayed means, operative independently of the speed of the mechanical load device, for delayedly resetting said movement-responsive means to its non-responsive position after a cessation of movement of the transportation-device.

4. Mechanism for driving a mechanical load device on a movable transportation-device, comprising electrical driving-means for at times driving said mechanical load device, mechanical driving-means motivated by the movement of the transportation-device for at times driving said mechanical load device, said electrical and mechanical driving-means being each effectively operative only upon the fulfillment of certain predetermined conditions, speed-responsive means responsive to the speed of the transportation-device, said speed-responsive means being operative in response to increasing speeds of the transportation-device for fulfilling a condition necessary to the functioning of the mechanical driving-means in response to a transportationdevice speed above a predetermined value, said speed-responsive means being operative in response to decreasing speeds of the transportation-device for insuring that the aforesaid mechanical driving-means is substantially inoperative in response to a transportation-device speed below a predetermined value, time-delayed means, operative independently of the speed of the mechanical load device, and delayedly responsive to a substantially complete cessation of movement of the transportation-device for fulfilling a condition necessary to the functioning of the electrical driving-means, and means, cooperating with said time-delayed means, for insuring a deenergization of the electrical drivingmeans when the transportation-device barely begins to move,

5. Mechanism for driving a mechanical load device on amovable transportation-device, comprising electrical driving-means for at times driving said mechanical load device, mechanical driving-means motivated by the movement of the transportation-device for at times driving said mechanical load device, said electrical and mechanical driving-means being each effectively operative only upon the fulfillment of certain predetermined conditions, speed-responsive means responsive to the speed of the transportation-device, said speed-responsive means being operative in response to increasing speeds of the transportation-device for fulfilling a condition necessary to the functioning of the mechanical driving-means in response to a transportationdevice speed above a predetermined value, said speed-responsive means being operative in response to decreasing speeds of the transportation-device for insuring that the aforesaid mechanical driving-means is substantially inoperative in response to a transportation-device speed below a predetermined value, time-delayed means, operative independently of the speed of the mechanical load device, and delayedly responsive to a substantially complete cessation of movement of the transportation-device for fulfilling a condition necessary to the functioning of the electrical driving-means, and means responsive to a predetermined short distance of travel from standstill, substantially regardless of speed, and cooperating with said time-delayed means, for insuring a deenergization of the electrical driving-means when the transportationdevice begins to move.

6. Mechanism for driving a mechanical load device on a movable transportation-device, comprising electrical driving-means for at times driving said mechanical load device, mechanical driving-means motivated by the movement of the transportation-device for at times driving said mechanical load device, said electrical and mechanical driving-means being each effectively operative only upon the fulfillment of certain predetermined conditions, speed-responsive means responsive to the speed of the transportation-device, said speed-responsive means being operative inresponse to increasing speeds of the transportation-device for fulfilling a condition necessary to the functioning of the mechanical driving-means in response to a transportationdevice speed above a predetermined value, said speed-responsive means being operative in response to decreasing speeds of the transportation-device for insuring that the aforesaid mechanical driving-means is substantially inoperative in response to a transportation-device speed below a predetermined value time-delay means responsive to a reduction of the speed of the transportation-device to a value below a predetermined low minimum for thereafter interposing a time-delay sufficient, in general, for the transportation-device to come to a complete rest, and for subsequently, after said time-delay. fulfilling a condition necessary to the functioning of the electrical driving-means, and means for insuring a deenergization of the electrical driving-means when the transportation-device barely begins .to move.

'I. Mechanism for driving a mechanical load device on a movable transportation-device, comprising electrical driving-means for at times driving said mechanical load device, mechanical driving-means motivated by the movement of the transportation-device for at times driving said mechanical load device, said electrical and mechanical driving-means being each effectively ope ative only upon the fulfillment of certain predetermined conditions, speed-responsive means responsive to the speed of the transportation-device, said speed-responsive means being operative in response to increasing speeds of the transportation-device for fulfilling a condition necessary to the functioning of the mechanical driving-means in response to a transportationdevice speed above a predetermined value, said speed-responsive means being operative in response to decreasing speeds of the transportation-device for insuring that the aforesaid menecessary to the functioning of the mechanical driving-means in response to a transportationdevice speed above said materially higher speed and for insuring that the aforesaid mechanical driving-means is substantially inoperative in response to a transportation-device speed below said materially higher speed.

10. Mechanism for driving a mechanical load device on a movable transportation-device, comtravel from standstill, substantially regardless of speed, for insuring a deenergization of the electrical driving-means when the transportationdevice begins to move.

8. Mechanism for driving a mechanical load device on a movable transportation-device, comprising electrical driving-means for at times driving said mechanical load device, mechanical driving-means motivated by the movement of the transportation-device for at times driving said mechanical load device, said electrical and mechanical driving-means being each efiectively operative only upon the fulfillment of certain predetermined conditions, means operative at the first movement of the transportation-device, upon starting from standstill, for insuring a deenergization of the electrical driving-means when the transportation-device barely begins to move, time-delayed means, cooperative with said movement-responsive means substantially independently of the speed of the mechanical load device, and delayedly operative after the transportation-device has decelerated toa very low speed, for fulfilling a condition necessary to the functioning of the electrical driving-means, and means responsive to a materiallyhigher speed of the'transportation-device for fulfilling a condition necessary to the functioning of the mechanical driving-means in response to a transportation-device speed above said materially higher speed and for insuring that the aforesaid mechanical driving-means is substantially inoperative in response to a transportation-device speed below said materially higher speed.

9. Mechanism for driving a mechanical load device on a movable transportation-device, com-- prising electrical driving-means for at timesv driving said mechanical load device, mechanical driving-means motivated by the movement of the transportation-device for at times driving said mechanical load device, said electrical and mechanical driving-means being each effectively operative only upon the fulfillment of certain predetermined conditions, means operative at a very low speed of the transportation-device, upon starting from standstill, for insuring a deenergization of the electrical driving-means when the transportation-device begins to move, time-delay means responsive to a reduction of the speed of the transportation-device to a value below a predetermined low minimum for thereafter interposing a time-delay sufllcient, in general, for the transportation-device tocome to a complete rest, and for subsequently, after said time-delay, fulfilling a condition necessary to the functioning of the electrical driving-means, and means .re-

. sponsive to a materially higher speed of the transportation-device for fulfilling a condition prising electrical driving-means for driving said mechanical load device when the transportationdevice is stationary, mechanical driving-means motivated by the movement of the transportation-device for driving said mechanical load device when the transportation-device is moving, a pair of pivoted arms, means for biasing said arms toward normal positions, means motivated by the initial movement of the transportation-device for alternately actuating said arms, one at a time, to their actuated positions, arm-holding means operative to retain each arm in its actuated position once it is actuated, and means for insuring the deenergization of the electrical drivingmeans when both of said arms are in their actuated positions at the same time.

11. Mechanism for driving a mechanical load device on a movable transportation-device,comprising electrical driving-means for at times driving said mechanical load device, mechanical driving-means motivated by the movement of the transportation-device for at times driving said mechanical load device, said electrical and mechanical driving-means being each effectively operative only upon the fulfillment of certain predetermined conditions, and controlling-means for said electrical driving-means, comprising a pair of pivoted arms, means for biasing said arms toward normal positions, means motivated by the initial movement of the transportation-device for alternately actuating said arms, one at a time, to their actuated positions, arm-holding means operative to retain each arm in its actuated position, once it is actuated, time-delay means responsive to a reduction of the speed of the transportation-device to a value below a predetermined low minimum, and further responsive to both of said arms being in their actuated positions, for thereafter interposing a material timedelay and for subsequently, after said time-delay, releasing said arm-holding means, and means for fulfilling a condition necessary to the energization of the electrical driving-means in response to either one of said arms being in its normal non-actuated position, and for insuring the deenergization of the electrical driving-means in response to both of said arms being in their actuated positions.

l2. Mechanism for driving a mechanical load device on a movable transportation-device, comprising a storage battery, a direct-current dynamo-electric machine operative either as a generator to charge said battery or as a motor energized therefrom, mechanical driving-means between said mechanical load device and said electric machine, speed-responsive engageable and disengageable mechanical driving-means motivated by the movement 'of the transportation-device for driving both the mechanical load device and the electric machine, reversibly movable reversing-switch means having biasingmeans for restoring the same to a neutral central position, slip-permitting actuating-means motivated by the movement of the transportationdevice in either direction for applying actuatingforce to said reversing-switch means depending.

in direction and amount, upon the direction and speed of movement of the transportation-device, first and second forward-responsive contactmechanisms actuatable at different forward displacements of said reversing-switch means, first and second backward-responsive contact-mechanisms actuatable at different back ward displacements of said reversing-switch means,

means for reversing the field of said dynamovoltage, said second contact-mechanisms being actuatable at a speed of the translating device lower than the speed at which said reverse-current means operates, and motor-controlling means for controlling the connection of the electric machine to the battery for motoring operation in a predetermined manner responsive to a non-actuated condition of both of said first contact-mechanisms.

13. Mechanism for driving a mechanical load device on a movable transportation-device, comprising a storage battery, a direct-current dynamo-electric machine operative either as a generator to charge said battery or as a motor energized therefrom, mechanical driving-means between said mechanical load device and said electric machine, speed-responsive engageable and disengageable mechanical driving-means motivated by the movement of the transportationdevice for driving both the mechanical load device and the electric machine, reversibly movable reversing-switch means having biasingmeans for restoring the same to a neutral central position, slip-permitting actuating-means motivated by the movement of the transportation-device in either direction for applying actuating-force to said reversing-switch means depending, in direction and amount, upon the direction and speed of movement of the transportation-device, first and second forward-responsive contact-mechanisms actuatable at different forward displacements of said reversing-switch means, first and second backward-responsive contact-mechanisms actuatable at different backward displacements of said reversing-switch means, means for reversing the field of said dynamo-electric machine in accordance with which of said second contact-mechanisms was last actuated, reverse-current means for connecting and disconnecting said electric machine to and from the battery to control the generator-operation of said machine in accordance with its senerated voltage, said second contact-mechanisms being actuatable at a speed of the translating non-actuated condition of both of said first contact-mechanisms, and further responsive to both of said arms being in their actuated positions, for thereafter interposing a material time-delay and for subsequently, after said time-delay, releasing said arm-holding means, and means for fulfilling a condition necessary to the energiza-tion of the electric machine as a motor, in response to either one of said arms being in its normal non-actuated position, and for insuring the deenergization of the electric machine as a motorin response to both of said arms being in their actuated positions.

14. Mechanism for driving a mechanical load device on a movable transportation-device, comprising electrical driving-means for at times driving said mechanical load device, mechanical driving-means motivated by the movement of the transportation-device for at times driving said mechanical load device, said electrical and mechanical driving-means being each effectively operative only upon the fulfillment of certain predetermined conditions, speed-responsive means responsive to the speed of the transportationdevice, said speed-responsive means being operative in response to increasing speeds of the transportation-device for fulfilling 'a condition necessary to the functioning of the mechanical driving-means in response to a transportationdevice speed above a predetermined value, said speed-responsive means being operative in response to decreasing speeds of the transportation-device for insuring that the aforesaid mechanical driving-means is substantially inoperative in response to a transportation-device speed below a predetermined value, said electrical driving-means comprising a storage battery, a directcurrent dynamo-electric machine, a double-duty main contactor-switch for connecting and disconnecting said dynamo-electric machine to and from the battery for both motoring and generating operation, mechanical driving-means motivated by the movement of the transportationdevice for at times driving said dynamo-electric machine, a reverse-current switch for fulfilling a condition necessary to the closure of said main contactor-switch in response to an operational condition which qualifies the dynamo-electric machine to charge said battery and for effecting the opening of said main contactor-switch in response to an operational condition which disqualifies the dynamo-electric machine from charging said battery, means so interrelated to the decreasing-speed response of said speed-responsive means as to be operative only subsequently thereto in response to decreasing speeds of the transportation-device for fulfilling a condition necessary to the closure of said main contactor-switch, movement-responsive means for insuring an opening of said main contactorswitch when the transportation-device barely begins to move, and time-delayed means, operative independently of the speed of the mechanical load device, for delayedly resetting said movement-responsive means to its non-responsive position after a cessation of movement of the transportation device.

WALTER H. SMITH.