GB235936A - Improvements in and relating to the starting of electric motors - Google Patents

Abstract

235,936. British Thomson-Houston Co., Ltd., and Watson, G. O. March 22, 1924. Controllers, with auxiliary switches and no-volt release; sliders.-A starter 4 of a motor, such as an alternating current motor 1 supplied from mains 2 through a circuit breaker 3, has an electrical interlock 8 which is independent of the starter, and which has to be kept closed during the starting operation. The circuit breaker is held closed by a low-voltage release coil 10, the circuit of which is completed through an interlock 6 when the starter 4 is in its initial position. Closure of the circuit breaker causes the closure of an associated switch 5, so that the circuit of the coil 10 can be maintained during advance of the starter, provided that the interlock 8 is kept closed by the operator. In its final position. the starter 4 closes an interlock 7, so that the operator can then release the interlock 8. Should the circuit breaker open, either due to failure of voltage across the mains, or of the operator to keep the interlock 8 closed while the starter is between its end position, it is necessary to return the starter to its initial position before the circuit breaker can be closed again. The starter may be arranged to close the interlock 8 mechanically in its final position and so obviate the use of the interlock 7.