Patent GB-348516-A (GB)
Title: Improvements in or relating to the control of steam locomotives
IPC: B60L15/42
Filed: 1930-02-03
Abstract: 348,516. Controlling locomotives from a distance; electric motor control systems. IGRANIC ELECTRIC CO., Ltd., 147, Queen Victoria Street, London, KITSON & CO., Ltd., Airedale Foundry, Leeds, and TAYLOR, J. R., Monterey, Uddingston, Glasgow. Feb. 3, 1930, No. 3617. [Class 79 (v).] A control apparatus for steam locomotives has the regulator valve driven by means of an electric motor controlled by means of a control in the driver's cab in such a way that said regulator valve is adapted to be moved automatically to a position corresponding to that of said control. The reversing-gear may be controlled in a similar manner. According to another feature of the invention apparatus for controlling a distant device driven in reverse directions by means of an electric motor comprises a generator in constant rotation and permanently in circuit with said motor, and means whereby the potential at one end only of the field winding of the generator varies in accordance with variations in the position of an element at the control station, and the potential at the other end only of said field winding varies in accordance with variations in the position of the motor, the relation of the variations in said potentials to the variations in the positions of said element and said motor being such that when said element is in registration with the distant driven device said two potentials are equal and the motor is deenergized and when said element is moved out of registration with said device the difference in said potentials causes a flow of current through said field winding in such a direction that the motor is energized for bringing said device into registration with said element whereupon said field current ceases and said motor is again de-energized. In the construction shown a locomotive regulator valve 1 is controlled by a motor 3 of which the armature is connected directly across the armature of a constantly-driven generator 5 and the field winding 7 is constantly energized by an exciter generator 9. The locomotive reversing-gear 2 is similarly controlled by a motor 4 having an armature connected directly across the armature of a generator 6, the generators 9, 5, 6 being constantly driven by an auxiliary steam engine not shown. The generator 9 is shunt wound to develop a constant voltage across its terminals, and across these terminals there are connected in parallel, in addition to the field windings 7, 8, two potentiometer resistances 10, 11 situated in the locomotive, and two potentiometer resistances 12, 13 situated in the driver's cab. The field winding 14 of the regulator generator 5 is connected between the sliding contact 15 of resistance 10 and the sliding contact 16 of resistance 12, so that when these contacts are similarly placed on the resistances no current flows through the field winding 14, and the generator 5, and, therefore, the regulator motor 3, are not energized. When the driver moves the contact 16 of resistance 12 a potential difference is created across the field winding, the generator 5 is energized and drives the motor 3 in the corresponding direction to open or close the valve 1. At the same time the motor 3 moves the sliding contact 15 through the gearing shown until this contact reaches a position corresponding to that of the driver's contact 16, when the field winding 14 is de-energized and the motor 3 stops. The reversing-gear is controlled in a similar manner. An emergency circuit extends from the generator 9 through a switch 26 and a resistance 27 in the driver's cab, a solenoid 22 and contacts 23 controlled thereby, and a trip coil 24 controlling a cut-out 25. Normally the switch 26 is closed and the emergency circuit energized, and the solenoid 22 holds an emergency valve 21 open if that has been first opened by hand. If the switch 26 is opened the solenoid is de-energized and the valve 21 closes thus shutting off the steam supply. Breaking the cable between the locomotive and the driver's cab has the same effect, and if a short-circuit occurs which cuts out the resistance 27 the trip coil 24 will be sufficiently energized to open the contacts 25 and thus allow the valve 21 to close. A switch 35 enables the emergency circuit to be re-established when the valve 1 is closed but not when it is open. There may be more than one control position, the one in use being selected by a switch. Five conductor wires extend between the locomotive and the driver's cab, 28 for the emergency circuit, 30 to the positive end of both driver's resistances, 31, 32 to the respective sliding contacts, and a return conductor 29.