GB221213A - Improvements in and relating to heat-responsive electric circuit-controllers - Google Patents

Abstract

221,213. British Thomson-Houston Co., Ltd., (Assignees of Eaton, J.). Aug. 27, 1923, [Convention date]. Protective arrangements; automatic circuitbreakers.-A protective arrangement for a motor or other device 12 comprises a thermal element 13, the heating coil 14 of which is connected in the motor circuit, and which upon overload bends to the right and allows a switch 10 to open; this in turn opens the motor circuit and as the element 13 cools its lower end bearing against the right side of a catch 19 on a member 15 rotates the member 15 into engagement with a contact 22 thereby closing the circuit to an electromagnet 16 which attracts an armature 17 and brings all parts back to their original position. The member 15 is pivoted to the armature 17 and is biassed to the position shown by a spring. As an additional precaution an electromagnet 23 may be provided in the motor circuit, adapted on a large overload of short duration to attract an armature 24 on the member 15, thereby rotating the member 15 free from the element 13. The switch 10 opens and the apparatus is reset as before. Fig. 5 shows a modification in which the contact 22 is replaced by a member 25 adapted to be rotated step by step by a catch 26 on the member 15. After the circuit-breaker has opened and closed a certain number of times an insulating sector 28 prevents the member from completing the circuit of the electromagnet 16, and the circuit-breaker remains permanently open. Later on it may be reset by closure of a switch 29.