GB190418293A - Improvements in Controllers for Electrically Operated Capstans and the like - Google Patents

Abstract

18,293. Scott, W. H. Aug. 23. Motors, controlling.-Relates to the construction, operation, and arrangement of the various switches and devices appertaining to controllers of the relay type for electrically-operated capstans and the like. The auxiliary controller X controls the operation of the reverser AB, the resistance switches 1-7, the overload device F, and the no-load and safety device G. The reverser. Fig. 2, has four magnets a arranged in pairs to rock the switch to give the desired direction of rotation in such a wav as forcibly to hold off the other contacts. This is effected by the slotted link C and pins c. To prevent the resistances operated by the relay magnets 1-7 from being operated too quickly, either the contacts D, E may be provided with dash-pots or equivalent devices, or a time-switch, Fig. 3, with a dash-pot e is arranged on each pair of the reverser relays, which switch is in circuit with the next relay through the contacts M. The other relay magnet coils 3-7 are preferably connected across the motor armature, and so adjusted that they are successively brought into action according to the voltage across the armature. The final relay switches 6, 7, which are liable to shortcircuit the starting-resistances, may also be provided with time switches. The armature f of the overload device, Fig. 4, can break the current operating the relays at L, so as either to break the motor circuit or introduce resistance therein as shown in Fig. 1. The current at which the armature f falls is adjusted so that hunting is prevented, the action being automatic. The coil G of the overload and safety device is in series with two sets of lamps H, and closes, by the switch J, the circuit of the reverser and the first part of the relay switches. When both resistances H are in series, the armature of the magnet G is down, but is raised when one of them is short-circuited and can then be retained by both resistances in series. In the ' off ' position the plate K short-circuits one resistance, and during starting the resistances are in series and the switch J remains closed. The result of this is that failure of the voltage from any cause necessitates moving the controller B to the ' off' position, and prevents damage to the motor.