GB215762A - Improvements in and relating to protective devices for electric lamp regulators - Google Patents

Abstract

215,762. Dick, E. May 7, 1923, [Convention date]. Protective systems with fuses.-The movable contact 10 and resistance 9 of an automatic regulator for a train lighting installation, are automatically protected against excess current flowing through the resistance by the actuation of a relay 20 short-circuiting the resistance through contacts 19, 22 and a coil 17, this short circuit being interrupted after the excess current has vanished. The contact 10 is displaced automatically in accordance with the lamp voltage by a solenoid 11 connected in series with an adjustable resistance 12. A coil 16 of an electromagnet is connected as a shunt across the resistance 9, so that on the occurrence of excess current through the resistance 9, the electromagnet is energized sufficiently to attract the armature of the relay and close the short circuit 19. 22, 17, the excess current through the coil 17 maintaining the relay in its displaced position. Upon cessation of the excess current, for example, by the blowing of one of the fuses 15, a spring 21 returns the relav to its normal position. When the relay 20 is actuated, contacts 19, 23 are also closed, thereby short circuiting the solenoid 11 to allow the contact 10 to return to its normal position, alternatively this may be effected by interruption of the solenoid circuit. The coil 16 may be subdivided and connected to corresponding parts of the resistance 9 so that only portions of this coil are effective according to the position of the contact 9. Several coils in series with separate sections of the resistance 9 may be used in addition to or in place of the coil 16.