Patent GB-190312315-A (GB)
Title: Improvements in Electric Motor-control Systems.
Inventor: CAROLAN EDGAR ALFRED
Filed: 1903-05-29
Granted: 1904-05-28
Abstract: 12,315. Carolan, E. A., [General Electric Co.]. May 29. Motors, controlling. - Motor control systems, especially systems having controllers of the separately-actuated contact type, are arranged so as to be automatic during the whole or any part of the period of acceleration of the motor or motors. The systems are especially applicable to motors carried by cars or vehicles coupled together to form a train. Each car has a controller the elements or contacts of which are operated by means, such as a number of relays or electromagnetically.actuated switches, constructed and arranged so as to respond successively to the counter electromotive force developed in the motor circuit as the speed rises. The coils of the relays are preferably connected in series across the terminals of one of the motors. The controller is also provided with means for automatically changing the motors from the series to the parallel position. A master controlling-switch is provided at each end of each car whereby the acceleration of the motors may be arrested in either the final series or the final parallel position. Fig. 1 shows the invention as applied to a car having train wires 2, 3, and 4, master control switches C<1>, C<2>, and motors M', M<2>, connected to the train wires &c. by an automatic control switch comprising electromagnetically-actuated contacts T', R' to R<6>, R<8>, S, and P. The series connections are controlled by contacts T<1>, R', and S, and the parallel connections by contacts T<1>, R', and P. R<3> to R<6> are resistance-controlling contacts, and the contacts R<8> control the arrangement of the motors. Resistances R<a> to R/ and r<1> to r<4> are arranged as shown. These contacts are controlled by relays A to H suitably arranged in the car and connected across the terminals of the motor M<2>. The relays A to D govern the operation of the resistance contacts while the motors are in series, and the relays E to H while the motors are in parallel. They come into action in alphabetical order. Relays I, K, actuated simultaneously between the relays D and E, are also connected in shunt with the motor M<2>. When in their de-energized positions, they control the series combination of contacts and also complete the circuit through the actuating-coils of the series resistance relays. In their energized positions, they control the parallel combination of contacts and complete the circuit through the coils of the parallel resistance relays. Each relay has two pairs of contacts as shown. The two relays may be replaced by a single one. The controllers C<1>, C<2> have each movable contacts a to e adapted to connect fixed contacts 1<a> to 5<a> connected to the automatic controller as shown. The arrangement operates as follows :-When the controller C' is turned to its series position, the contacts 1<a> and 2<a> are connected together, and the contact 4<a> is connected to earth. The circuit from the trolley is then completed through the actuating-coils of the contacts T', R', the resistance r<4>, the actuating- coil of the contact S, an auxiliary switch k' carried by one of the contacts P, and back through the controller C' to earth. The operation of these contacts closes a circuit through the contacts T', R<1>, resistance R<a>, motor M<1>, contact S, and motor M' to earth. As the speed of the motor increases, the relays A to D are successively operated by the counter electromotive force, thereby successively cutting in the resistances R<c>, R<d>, &c. in parallel with the resistance R<a>, and finally cutting out all resistance by the actuation of the contacts R. To increase the speed further, the controller C' is tnrned to the parallel position, the contact 3<a> being then connected to earth. The relays I, K are operated by the increased counter electromotive force. The circuit now includes the actuating- coils of the contacts T', R<2>, P, auxiliary switch contacts k of the series contact S, and contacts 17 of the relay I. The motors are thus connected in parallel with each other, and in series with the resistance R<6>. The relays E to H are now actuated successively to reduce and finally to cut out the resistance in a similar manner to that of the relays A to D. If the controller C<1> is turned at once to its parallel position, the parts are actuated automatically in the same order.