GB444399A - Improvements in and relating to fault detecting and cutting out systems for electricsupply circuits - Google Patents

Abstract

444,399. Protective cut-out arrangements. BRITISH THOMSON-HOUSTON CO., Ltd., Crown House, Aldwych, London, and BUTLER, F. E., 74, Eastlands Road, and JEWITT, D. E., 17, Hillmorton Road, both in Rugby. Sept. 19, 1934, No. 26934. [Class 38 (v)] Apparatus for detecting and cutting out faults in supply systems consisting of a number of circuits, particularly on ships, where insulation failures are frequent, comprises a relay Y connected to the supply mains and adapted to be operated by the occurrence of a fault to complete the circuit of a motor M, which drives a generator G to apply a testing current to the circuits in turn and automatically cuts out the faulty one. Two power circuits are shown connected by solenoid-operated contactors K, with overload relays L, to bus-bars N, across which is a resistance having its mid point earthed through the coil of the relay Y. An insulation fault on a conductor or conductors causes the relay Y to start the motor M which drives the generator G and also a multi-contact switch, which has a set of three contacts A .. C for each circuit and, by its rotation, causes each circuit to be opened in turn at A and a testing current to be supplied from G to each opened conductor in turn over contacts B, C. If there is a fault on the conductor under test, the detector P trips contacts R and permanently disconnects the circuit containing that conductor. Should there be a further fault on the system, the motor M will go on testing the circuits in turn until the fault has been found and disconnected, whereupon Y stops the motor.