Patent GB-190508196-A (GB)
Title: Improvements in or relating to Multiple-unit Control for Electric Motors.
Inventor: PERKINS THOMAS STEEL
Filed: 1905-04-17
Granted: 1905-10-26
Abstract: 8196. Perkins, T. S., and Jackson, R. P. June 6, 1904, [date applied for under Patents Act, 1901]. Switches.-Relatestothemultipleunit control of electric motors, and comprises improvements in the means for operating the controller drums of the units, and in the means for controlling the acceleration and preventing overload. Fig. 1 shows the general arrangement for one vehicle. The master - controllers 1 control the reversing - switch 2 and the drum controller 5, which controls the switches 9 for controlling the resistances 65, 66 and the series-parallel connexions. The controller drum 5 operates automatically to cut out the resistances &c., but it may be stopped at any point by a simple movement of the mastercontroller. A limit device is provided to prevent the rotation of the drum should the current exceed a limit, and in case of overload a switch is opened and the master-controller must be moved to the 'off' position before current can again be supplied to the motors. The system can be worked with four train-wires, two for the reversing-switch and one each for full series and full parallel. If more 'running' positions are required, one additional wire is required for each position. In operation, the first movement to F or R of the master-controller closes a circuit through one or other of the actuating-magnets 16, 19 of the reversing- switch 2, throwing it into or retaining it in the position required. A circuit is then closed through one of the magnets 24 of the actuating-mechanism 6 of the drum 5. This magnet raises a pawl 27, and serves to retain the drum in any position into which it may subsequently be moved. A shunt circuit through a switch 29 energizes a magnet 30 and closes a switch 39. In the next position, say S, of the master-controller, contact is made at 31, and a circuit is closed through the blow-out coil 12 and also through the coil of the actuating-magnet 37. The drum 5 is then rotated through the ratchet mechanism 40, 28, the magnet 37 being successively de-energized and energized, by the operation of the switches 29, 39, until the drum has reached the full-series f, when the circuit through the magnet 37 is broken. A resistance 38 is in shunt to the magnet 37, and governs the rapidity of operation. This resistance may be fixed, or may be variable and under the control of the operator. The drum 5 controls the separately-actuated switches 9. In connexion with the switch 60 an interlocking switch 17 is provided in the circuit of the actuating-magnet of the reversing-switch, so that it can only be operated when the drum is in the 'off ' position. Should an overload occur, the coil 64 operates an arm 117 and releases a catch 119 on the controller drum, allowing the switch 59 to open and open the circuits of the coils 9. The switch 59 cannot be closed until the drum has been returned to the 'off' position, when a stop 118 engages the catch 119 and closes the switch. A series of resistances 80 are included in the circuits of the switch coils 9 and so proportioned as to equalize the resistances of the circuits. To prevent the motors from taking too much current during acceleration, a connexion is made from a point on the farther side of one of the field magnets 74 to one of the magnets 41 forming part of the controlling and actuating means for the drum 5, and serves to neutralize its effect should the current be excessive. This current is obviously of small voltage, and can be varied by varying the resistance or its point of connexion with the magnet winding. The wire 10 connected to the trolly may be made a train-wire, so that, should the collector T fail, current may be taken from the collectors on the other cars. The Specification in the original form as published under the Act of 1901 comprises also the details of the construction of the appliances used in the system. The master-controller, Figs. 3 and 4, is provided with a blow-out coil 12, which blows the arc outwardly in all cases. The coil is placed between the drum segments 118, 119 and separated by insulating-pieces 126. A spring 136 is provided for opposing the rotation of the handle. A motor controller is shown in Figs. 7, 8, and 10, which indicate the arrangement of the ratchet-and-pawl aotuating-mechanism 28, 25, 40, the interlocking switches, and the tripping-coil 64. This subjectmatter does not appear in the Complete Specification as accepted.