Patent GB-190312802-A (GB)
Title: Improvements in Controlling Electric Motors, particularly for Electrically Propelled Vehicles.
Filed: 1903-06-06
Granted: 1904-05-12
Abstract: 12,802. Siemens Bros. & Co., Siemens, A., and Duke, A. M. June 6. Motors, controlling. -Relates to a motorcontrol system, particularly for use on electrically - propelled vehicles and trains, and consists of a combination of the autom a t i c regulating- system described in Specification No. 27,618, A.D. 1902, with the system described in Specifications Nos. 21,648 and 27,619, A.D. 1902, for changing from series to parallel working of the motors of the separate pairs. In controlling the motors from either of the controllers on any of the vehicles, the motors are at first in series with each other and with a resistance, which is automatically cut out section by section as the speed increases; further movement of the movable controller - contact connects the motors in parallel branches each containing half the resistance, this resistance being then cut out automatically as before. The controller may be set at starting for connecting the motors in parallel, but the arrangements are such that the motors are actually at first connected in series with a resistance, and this is automatically cut out, as the speed increases, before the parallel connections come into operation. By the arrangements described, three wires are sufficient for controlling several groups of motors from anyone controlling-station. The switches used are all of the plunger type described in Speci6cation No. 28,012, A.D. 1902, [Abridgment Class Electricity, Regulating &c.]. For forward driving, the controller contact c, Fig. 1, is first moved on to the fixed contact c', and current then flows from the positive shoe A and the controlling-current lead 4 through a circuit 8, Figs. 1 and 3, to automatic switches AS and the negative shoe B. The switches AS then close the leads 21, 22. Assuming that both motors L', L<2> are in order, a branch 9 from the circuit 8 to the leads 24, 22 is closed at the double-pole reversing- switches D', D', Figs. 1 and 4, and the switch r, Fig. 3, is operated to connect the leads 37, 38, Figs. 2 and 3, and thus to complete the series motor circuit. This circuit comprises the lead 21, switch D', leads 29, 31, 33, 35, motor L', leads 25, 39, whole resistance R', leads 37, 38, whole resistance R', leads 26, switch D', motor L', and lead 22. Passage of current through this circuit breaks the circuit 8 at the switch m, and leaves the switches AS free to open the leads 21, 22 if the motor current becomes excessive or ceases. The resistance switches are operated by current in a circuit 12 branching from the circuit 8 between the switches s, p<1> and containing two coils SC<1>, SC<2> and two adjustable resistances r', r<2> in two branches at the resistance switch. The other ends of these branches join a lead 13 which connects with the circuit 9 either through the switch r or through the switches p<1>, p', a resistance r<3> being introduced in the latter case to retard the cutting out of the resistance sections when the motors are in parallel. The motor current falls off after the motors have started running, and the actions of the coils MC<1>, MC<2> on the switches t<1>, t' are then overcome by the coils SO', SC<2>, circuits 19, 20 being thus closed at these points. The circuit 19 being completed across to the other part of the circuit 12 through the contacts d, d<1> of the switch PS' No. 1, the contacts b, b<1> of the switch PS<1> No. 2, and the solenoid PS' No. 1, the switch PS' No. 1 is operated to connect the leads 25, 41, and so to cut out the first section of the resistance R<1>. The circuit 19 is then broken, and the circuit 12 completed across the contacts a, a' and through the solenoid of the switch PS' No. 1. When more resistance requires to be cut out, the circuit 20 comes into action and energizes the solenoid PS<2> No. 1 so as to connect the leads 26, 42, and to cut out the first section of the resistance R; the solenoid PS' No. 1 remains energized similarly to the solenoid PS' No. 1 after the circuit 20 is broken. These actions continue throughout the two series of switches PS', PS', each switch as it operates cutting off current from the previous one of the same set, so that finally the leads 25, 37 and 26, 38 are directly connected by the only switches PS' No. 4 and PS' No. 4, remaining in the closed position. If the motor current again falls so that the switch t' closes the circuit 20, current flows through the circuits 20,11, 9 and operates the switch s to connect the leads 27, 28 and so to shorten the connection between the leads 25, 26 of the motor circuit. The switch s also disconnects the circuits 8, 12, thereby allowing the switches PS' No. 4 an PS<2> No. 4 to open, and remains energized by current from the circuits 9, 11. When turning the controller C into the "parallel" position, the circuit 9 is at first still supplied with current from the leads 5, 8, but the circuit 10 is also supplied from the lead 6, so that the switches p<1>, p<2> break the circuit 9 and connect the leads 23, 38 and 24, 37. The motor circuit is thus split into two branches. One branch comprises the lead 21, switch D', motor L', lead 25, whole resistance R', and leads 37, 24, 22, while the other comprises the leads 21, 23, 38, whole resistance R<2>, lead 26, switch D', motor L<2>, and lead 22. When the leads 27, 28 were disconnected at the switch s, the circuits 8, 12 were again connected, so that the operations of cutting-out the resistances R<1>, R' proceed as before. Moving back the controller contact c on to the contact c' breaks the motor circuits at the switches p<1>, p'. To reverse the motors, the contact c is placed on the contact c<3>, and the controlling-current in the circuit 14 then energizes the solenoids of the switches D', D<2> to reverse the motor connections and also to close the branch 15 between the circuits 14, 8. The resistance switches are then operated as already described, and the controller may also connect the contacts c, c<3>, c<2> for parallel working. If one of the motors fails, the corresponding switch D<1>, D<2> is opened by hand, so that the switch r cannot be operated to complete the series motor - circuit. If, however, the switch n is operated by hand to close the circuit 10, the parallel branch circuit through the other motor is completed when the controller is placed in the " parallel" position. Hand-switches h are placed in the lead 4 and in the connections 5, 6, and 7 between the contacts c<1>, c<2>, and c<3> and the three train wires 1, 2, 3 which connect the controllers of the several vehicles. A solenoid switch o in the connection 7 breaks the connection 5 when the motors are reversed.