US2094338A - Motor control system - Google Patents

Description

P 1937. B. o. AUSTIN ET AL 2,094,338

MOTOR CONTROL SYSTEM Filed Jan. 19, 1955 2 Sheets-Sheet l S R b WITNESSES: 0ft ab erDZa/Dhraym INVENTORS 36 5061? 0 A215 [1'72 and P 1937. B. o. AUSTIN ET AL 4,

' MOTOR CONTROL SYSTEM Filed Jan. 19, 1935 2 Sheets-Sheet 2 WITNESSES:

INVENTORS @M Basal/m 0. Austin and /V07'UB7Y077 H Willby.

TORN

Patented Sept. 28, 1937 UNITED STATES MOTOR CONTROL SYSTEM Bascum 0. Austin, Pittsburgh, and Norman H. Willby, Irwin, Pa., assignors to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application January 19, 1935, Serial No. 2,526

10 Claims.

Our invention relates, generally, to motor control systems and, more particularly, to systems for controlling the operation of the propelling motors of railway vehicles,

An object of our invention, generally stated, is to provide an automatic control system which shall be simple and efiicient in operation and which may be economically manufactured and installed.

A more specific object of our invention is to provide an automatic control system having a large number of accelerating steps.

Another object of our invention is to provide a switching unit having a plurality of contact members which are actuated in sequential relation by fluid pressure operated diaphragms.

A still further object of our invention is to provide for controlling the operation of a plurality of fiuid pressure actuated switching members in a simple and economical manner.

Other objects of our invention will be fully explained hereinafter or will be apparent to those skilled in the art.

According to one embodiment of our invention the acceleration of a railway motor is controlled by a switching unit of the manifold type which comprises a series of diaphragms operated by air pressure. Each diaphragm operates a contact device which may be so connected in an electrical circuit that it will either insert a resistor in the circuit or shunt a resistor from the circuit. The application of air pressure to the manifold causes a series of contact members to be closed in a predetermined order.

When air pressure is applied at one end of the manifold, the first contact member is immediately closed by operation of the first diaphragm. Air pressure is then applied to the manifold line by means of air ports and the second diaphragm is actuated to close the second contact member. In this manner air pressure is progressively transferred from one diaphragm to another and the contact members are closed in sequential relation either to shunt a resistor from or connect it in an electrical circuit, depending upon the requirements.

For a further understanding of the nature and objects of our invention, reference may be had to the following detailed description, taken in conjunction with the accompanying drawings, in which:

Figure 1 is a top plan view of a manifold switching unit constructed in accordance with our invention;

Fig. 2 is a view in section, taken along the line 11-11 of Fig. 1;

Fig. 3 is also a view in section, taken along the line IIIIII of Fig. 1; and

Fig. 4 is a diagrammatic view of a motor con trol system embodying our invention.

Referring now to the drawings, and particularly to Figs. 1, 2 and 3 thereof, the manifold switching unit shown therein comprises a plurality of resiliently mounted contact members I0, each of which is disposed to engage a fixed contact member II. Each one of the contact members I0 is mounted on one end of a horizontally disposed leaf spring I2, the other end of which is connected to an electrical conducting bar I3 that is secured to a horizontally disposed insulating member I4 by bolts I5, which extend through the springs I2 and the bar I 3 into the supporting member I4.

Each one of the fixed contact members II is disposed above, or below, its cooperating contact member I0 and is engaged thereby when the spring I2 is deflected in a manner hereinafter described. The contact members II are supported on bracket members I6 which are secured to an insulating panel IT by bolts I8. The contact members I I are secured to the brackets I6 by bolts I9.

It will be observed that the contact members I0 and II are disposed in two horizontal rows, one row being above the other with the contact members in the bottom row disposed between those in the top row. The bottom row of contact members I0 are supported by flexible springs I2 in a manner similar to the top row of contact members and they may be actuated downwardly to engage fixed contact members II, which are supported similarly to those in the top row.

As shown in Figs. 1 and 3, the fixed contact members I I are connected to resistors 2I, which are also disposed in two horizontal rows. The resistors 2I are mounted between the panel I! and a panel 22 and they are supported by the panels I! and 22. Each one of the top row of contact members I I may be connected to a pair of adjacent resistor elements by the brackets I6 and connectors 23. Likewise, each one of the bottom row of contact members may be connected to a pair of adjacent resistors. The resistors in the top row may be connected to those in the bottom row by connectors 24 and in this manner a continuous resistor may be formed which may be shunted from an electrical circuit step-by-step by actuating the resiliently mounted contact members IIl into engagement with the fixed contact members II in sequential relation.

In order that the contact members I0 may be successively operated to shunt the resistors 2I, a diaphragm 25, which may be composed of any suitable flexible material, such as rubber or a rubberized fabric, is provided for actuating each one of the contact members I 0. As shown, the diaphragms 25 are disposed in two rows, one row being mounted on top of a manifold plate 26 and the other row being on the bottom side of the plate. The plate .26 is centrally disposed between the springs |2, which support the contacts l0, and is secured in position between the support member I4 and the panel H by bolts 29 and 28, which extend through the member M and the panel l1, respectively, into the edge of the plate 26.

As shown, each one of the diaphragms 25 is provided with a centrally disposed raised. portion 3| and a relatively thin flat portion 32 which is clamped tightly against the manifold plate 26 by means of a plate 33 and. bolts 34. The plate 33 is provided with a circular opening 35, of a considerably larger diameter than the portion 3| of the diaphragm 25, to permit the portion 3| to move freely up and down to deflect the spring |2 which rests on the diaphragm. A metal cap 36 is placed on top of the diaphragm between it and the spring |2 to protect the diaphragm from wear.

Each diaphragm is provided with a circular groove 31 in the surface next to the manifold plate 26, thereby affording a space between a portion of the flat part 32 of the diaphragm and the manifold plate 26. As shown, the groove 31 extends approximately from the centrally disposed raised portion of the diaphragm to that portion which is engaged by the clamping plate 33. In this manner, space is provided between the diaphragm 25 and the manifold plate 26 to admit a pressure fluid for raising the central portion of the diaphragm to actuate the contact member l0 into engagement with the fixed contact member As shown in Fig. 4 the pressure fluid is applied to the diaphragm 25, disposed at the right-hand end of the manifold plate 26, through a pipe 38 which leads from a magnet valve 39, of a wellknown type. The magnet Valve 39 controls the admission of the pressure fluid to the manifold 26 from a supply reservoir 4|. A similar magnet valve 42, located at the left-hand end of the manifold, is provided for releasing the pressure fluid from the manifold line.

When fluid pressure is applied to the first diaphragm through the pipe 38, it is immediately raised and actuates the first contact member I9. As shown in Fig. 2 when the central portion 3| of the diaphragm 25 is raised from the top surface of the manifold plate 26, a port 43 is uncovered and the pressure fluid is admitted to a chamber 44, which extends practically the entire length of the manifold plate, but is closed at both ends of the manifold plate.

Referring to Fig. 2, it will be seen that small ports 45 extend through the manifold plate 26 and connect the groove 3'! in each one of the top diaphragms with similar grooves in the bottom diaphragms. Thus, when the pressure fluid is admitted into the groove 31 in the first-diaphragm of the series, it flows through the small port 45 into the groove 37 in the second diaphragm of the series, which is on the bottom side of the manifold plate, and this diaphragm is lifted slowly to uncover the port 43 in the center of the diaphragm. The uncovering of this port admits a large supply of fluid from the chamber 44 which quickly closes the contact members actuated by this diaphragm and provides full pressure to force the fluid through the small port for the next succeeding diaphragm. Thus the fluid pressure is progressively transferred from one diaphragm to another.

In order to prevent any one of the diaphragms from being raised by the fluid pressure until the preceding diaphragm has operated to close its I contact members, a bleeder valve 46 is provided...

to release the pressure fluid from each one of the grooves 31 in the diaphragms with the exception of the first diaphragm of the series. Each one of the bleeder valves 46 is operated by a lever 41 which is actuated by the first preceding diaphragm of the series to close the valve. As shown, each one of the levers 47 pivots at. 48 and engages the central portion 3| of a diaphragm. Thus, when the first diaphragm is raised, it closes the bleeder valve for the second diaphragm, which permits pressure to build. up under the second diaphragm, and when the second diaphragm is raised it closes the bleeder valve for the third diaphragm, and so on through the series.

In this manner, the diaphragms and the contact members are successively operated by fluid pressure in a definite sequence. The size of the port at each diaphragm determines the time required for the diaphragm to close the contact members which it controls and this time can be governed by the size of these ports. When it is desired to permit the contact members to open, the pressure fluid is released from the manifold through the release valve 42, which permits all the diaphragms to discharge into the exhaust line 49.

Referring to Fig. 4, the diagram shows how the manifold type switching unit may be utilized to control the acceleration of an electric motor 5|, of a type suitable for propelling an electric vehicle (not shown). Power for operating the motor 5| may be sup-plied through an overhead conductor 52 and a current collector 53, and the resistors 2| may be connected in series with the motor 5| to control the motor current.

As shown, the contact members l9 and H are disposed to shunt the resistors 2| from the motor circuit step-by-stepas the contact members l9 are successively actuated by the diaphragms 25 on the manifold plate 26. A pressure fluid, such as compressed air from the tank 4|, is admitted to the manifold through the magnet valve 39 and the contact members H] are actuated by the diaphragms 25 in sequential relation, in the manner described hereinbefore. The pressure may be released from the manifold through the magnet valve 42.

An electrically-operated line switch 54 is provided for connecting the motor 5| to the power source and a limit relay 55 controls the acceleration of the motor 5| in a manner well known in the art. The limit relay 55 is provided with a series coil 56 and two shunt coils 5? and 55, which are disposed to oppose the series coil 56. Thus, the rate of acceleration of the motor may be increased by energizing both of the shunt coils 51 and 58, thereby increasing the current required in the series coil 56 to lift the armature of the relay. 7

As shown, the contact members 59 of the limit relay control the operation of the release valve 42, which in turn governs the air pressure in the manifold 26, thereby governing the rate of operation of the diaphragms 25. When the motor current exceeds a predetermined value, the limit relay lifts and the magnet valve 42 opens to lower the air pressure and slow down the operation of the diaphragms. If it is desired to increase the rate of acceleration of the motor, both of the shunt coils 5i and 58 are energized, thereby increasing the motor current.

A master controller 6| is provided for controlling the operation o-f the line switch 54, the magnet valves 39 and 42, and also the energization of the shunt coils 51 and 58 on the limit relay 55.-

Thus, when the controller BI is on position a", the line switch 54 is closed to connect the motor to the power source. When the controller is actuated to position b, the magnet valve 39 is opened and the valve 42 closed to build up a pressure in the manifold to operate the diaphragms in the manner described hereinbefore.

The one shunt coil 58 on the limit relay is energized when the controller is on position b and the limit relay governs the motor current, which, as previously explained, may be increased by actuating the controller to position thereby energizing both of the coils 51 and 58. When the controller 6| is returned to the off position, the line switch is deenergized and also both magnet valves 39 and 42, thereby shutting off the supply of air to the manifold and releasing the pressure from the diaphragms, which permits the contact members l0 and II to open.

From the foregoing description, it is evident that we have provided a simple and economical means for controlling the operation of an electric motor. A large number of steps or resistance notches may be provided if desired, thereby affording smooth acceleration of the motor. The equipment herein described is light and compact and can be readily installed in an electric vehicle, such as a street car or trolley bus and the system can be made to respond quickly to the wishes of the operator to govern the performance of the car.

Since numerous changes may be made in the above-described construction, and different embodiments of the invention may be made without departing from the spirit and scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

We claim as our invention:

1. A manifold switching unit comprising a plurality of contact members, a manifold plate having a plurality of ports therein, a series of flexible diaphragm members for actuating the contact members in sequential relation, electrically controlled means for admitting fluid pressure to the first one of said series of diaphragms through one of said ports to operate the diaphragm, and means actuated by said diaphragms for controlling the operation of the next successive diaphragm by the fluid pressure in said ports, thereby operating said diaphragms successively.

2. A manifold switching unit comprising a plurality of contact members, a manifold plate having a plurality of ports therein, a series of flexible diaphragm members for actuating the contact members in sequential relation, electrically controlled means for admitting fluid pressure to the first one of said series of diaphragms through one of said ports to operate the diaphragm, means actuated by said diaphragms for controlling the operation of the next successive diaphragm by the fluid pressure in said ports, and means for releasing the fluid pressure from the diaphragms.

3. A manifold switching unit comprising a plurality of contact members, a manifold plate having a plurality of ports therein, a flexible diaphragm for actuating each one of said contact members, and means for applying fluid pressure to the diaphragms through said ports to operate them in sequential relation, said ports being disposed in the manifold to cause fluid pressure to be applied successively to said diaphragms.

4. A manifold switching unit comprising a plurality of contact members, a manifold plate having a plurality of ports therein, a flexible diaphragm for actuating each one of said contact members, means for applying fluid pressure to the diaphragms through said ports to operate them in sequential relation, and means for simultaneously releasing the fluid pressure from all of the diaphragms, said ports being disposed in the manifold to cause fluid pressure to be applied successively to said diaphragms.

5. A manifold switching unit comprising a plurality of contact members, a manifold plate, a series of diaphragm members mounted on the manifold plate for actuating the contact members in sequential relation, electrically controlled means for admitting a pressure fluid to the manifold plate to operate the first one of said diaphragm members, and means actuated by each one of said diaphragms for controlling the operation of the next diaphragm.

6. A manifold switching unit comprising a plurality of contact members, a manifold plate, a series of diaphragm members mounted on the manifold plate for actuating the contact members in sequential relation, means for admitting a pressure fluid to the manifold plate to operate the first one of said diaphragm members, means actuated by each one of said diaphragms for controlling the operation of the next diaphragm, and electrically controlled means for releasing the pressure fluid from the manifold plate.

7. A manifold switching unit comprising a plurality of contact members, a manifold plate having a plurality of ports therein, a series of diaphragm members disposed on the plate over said ports for actuating the contact members in sequential relation, electrically controlled means for admitting a pressure fluid to the manifold plate to operate the first one of said diaphragms and means actuated by each one of said diaphragms for controlling the operation of the next diaphragm.

8. A manifold switching unit comprising a plurality of contact members, a manifold plate having a plurality of ports therein, a series of diaphragm members disposed on the plate over said ports for actuating the contact members in sequential relation, means for admitting a pressure fluid to the manifold plate to operate the first one of said diaphragms, means actuated by each one of said diaphragms for controlling the operation of the next diaphragm, and electrically controlled means for releasing the pressure fluid from the manifold plate.

9. A manifold switching unit comprising a plurality of contact members, a manifold plate having a plurality of ports therein, a plurality of diaphragm members disposed on the plate over said ports for actuating the contact members, means for admitting a pressure fluid to the manifold plate to operate the diaphragms, and means actuated by the diaphragms to cause them to be operated in sequential relation.

10. A manifold switching unit comprising a plurality of contact members, a manifold plate having a plurality of ports therein, a plurality of diaphragm members disposed on the plate over said ports for actuating the contact members, means for admitting a pressure fluid to the mani fold plate to operate the diaphragms, and valve means actuated by the diaphragms to cause them to be operated in sequential relation.

BASCUM O. AUSTIN. NORMAN H. WILLBY.

Images