Patent GB-190407208-A (GB)
Title: Improvements in Controlling Systems for Electric Motors.
Inventor: WESTINGHOUSE GEORGE
Filed: 1904-03-25
Granted: 1904-10-27
Abstract: 7208. Westinghouse, G., and Aspinwall, L. M. May 1, A.D. 1903, [date applied for under Patents Act, A.D. 1901]. Motors, controlling.-In an electro - pneumatic control system for electric motors and for motor-driven vehicles and trains, such as are described in Specifications No. 4327, A.D. 1899, No. 11,835, A.D. 1900, and No. 7966, A.D. 1901, the electromagnets controlling the movements of the fluid-pressure valves actuating the motor-controlling switches are automatically and progressively energized in a predetermined manner after the governing-circuits have been completed by means of the master-controller. Fig. 1 is a diagram of the system as applied to two motors 101, 102, in which there are a reversing-switch 52, a reverser governing-switch 53, a governing-switch or mastercontroller 55, a limit switch 62, a battery 54, eleven interlocking switches 46, 47, 49, thirteen pneumatic cylinders 8 arranged in a circle and actuating thirteen switches 22, eight electromagnets 16 (five of which have pick-up coils 44 and retaining-coils 45), and resistances 120 to 130. Each pick-up coil is arranged in a branch of the preceding retaining- coil circuit, and is connected to a common return through the limit switch, and the corresponding interlocking switches are arranged so that, as each is closed by its corresponding pick-up coil, the governing-circuit is closed through the corresponding retaining-coil and the next succeeding pick-up coil. The master-controller 55 is moved to its first position to close the first and second switches 22, the circuit being through the battery 54, finger 112, contact 57, finger 110, circuit-breaker governing-switch 50, and the first coil 16 back to the battery. The switch 50 is normally closed, but is opened when an excessive current flows through its coil 51 from the trolley 100. The coil 16, when energized, operates a valve to allow air under pressure to enter the cylinders 8 of the first and second switches 22. The closing of the second switch 22 closes the first interlocking switch 46, which establishes a circuit from the positive terminal of the battery through the finger 112, strip 57, finger 111, reversing-switch 53, fingers 117 and 118 or 119, switch 67 of the reverser 52, circuit-breaker governing-switch 50, and the coil of the first magnet 16 to the negative terminal of the battery. The switch 67 is closed by means of one of the reversing-coils 106, which is in circuit with the battery. The second position of the switch 55 throws the motors in series with each other and with a suitable resistance. A branch circuit is then made from the junction 104 through the ninth switch 47, second magnet coil 16, finger 115, strip 58, and finger 116 back to the battery. This second magnet 16 operates a second valve to admit air to the corresponding cylinders 8 to actuate the third and fourth switches 22. The closing of the third switch closes the corresponding interlocking switch 46, and establishes. a motor circuit from the trolley 100 through the first and second switches 22, blow-out coil 42, fourth switch 22, resistances 120, 121, 122, 123, 125 and part of 128, reverser contacts 68, 69, 70, armature of the motor 101, reverser contacts 71, 72, 73, field magnet of the motor 101, third switch 22, reversing- contacts 74, 75, 76, armature of the motor 102, reversing-contacts 77, 78, 79, and Beld - magnet winding of the motor 102 to the ground 103. In the third position of the controller 55, the motors are thrown into series without resistance, the first pick-up coil 44 and retaining-coil 45 are energized, and the fifth switch 22 and its corresponding interlocking switch 49 are closed. The circuits set up by this condition of affairs result eventually in sending a current through the second, third, fourth, and fifth coils 44,45, and the closing of the sixth, seventh, eighth, ninth, and tenth switches 22, and of the fifth, sixth, and seventh interlocking switches 49, 46. The fourth position of the controller 55 results in throwing the motors into parallel with each other and into series with a suitable amount of resistance. In this position, the sixth pick-up coil 44 is first energized, the eleventh and tenth interlocking switches 46 are caused to close, and the ninth 47 to open, while all the first five retaining and pick-up coils and the corresponding interlocking switches and the switches 22 open. Moreover, the eleventh, twelfth, and thirteenth switches 22 close, as also the tenth interlocking switch 46. The sixth switch 22 again closes, and is followed by the closing of others as in the third position. When the governing-circuit is broken at the switch 50 by an excessive current, it cannot be completed again except by moving the master-controller to its first position. The system may be used with one, two, or more motors, and for controlling motors for propelling vehicles and trains and for other purposes. A suitable form of motor controller for use with this system is shown in Fig. 2, and an interlocking switch in Fig. 3. The controller 1 has a central hub 3 with radiating arms 4, a top casting 5, and an annular plate 6 bolted thereto. The casting has a central air chamber 7, and an annular series of cylinders 8, connected to the air chamber by passages 9, 10, 11, 12, the passages being controlled by a double valve 13, kept in its closed position by a spring and allowing the air to exhaust through an opening 15 to the atmosphere. It is opened by the governing-electromagnet 16. Each cylinder 8 has a spring piston 17, which actuates a bell-crank lever 21 connected by an insulating-bolt 25 to a terminal 28. An arm 29 is pivoted to the lever, and has a copper contact-shoe 30. It is maintained in position by a spring 31 and by stops 32, 33, and is electrically connected up by flexible copper strips 34. Insulating and, preferably, refractory boxes 35 are attached to the edge of the ring 6, and are provided with contact-plates 38 attached by heads 37 and insulated bolts 36 to terminals 39. These devices constitute the switches 22. The blow-out magnet is represented at 42. The interlocking switches 46, 47 may be rigidly connected to the piston, as shown in Fig. 2. Their construction may be such as is shown in Fig. 3, in which the head 80 of the cylinder 8 has a recess 82 for a buffer spring 83 adapted to receive the upward blow of the piston 17. The stem 84 of the casing contains a coiled spring 86, acting on a plunger 87 which is fastened to a rod 86. The top of the latter projects into a chamber 89 having a removable cap 90, and is connected to a non-conducting block 91 having a conducting-ring 92 provided with an annular set of downwardly-projecting spring arms 93, by means of which contact is made and broken between stationary terminal bolts 94, there being two or three such bolts arranged around the chamber 89. The contact is made when the piston is depressed, and broken when it is raised. In a modification, for use as the ninth switch 47 in Fig. 1, the coiled spring corresponding to 86 acts so as to move the spring arms out of engagement with the contacts.