Improvements in and relating to 'tell-tale' devices for indicating the failure of anelectric circuit

摘要

442,107. Detecting faults. DONALDSON, F. G., 14, The Parsonage, Manchester. Feb. 13, 1935, No. 4602. [Class 37] [See also Group XXXVIII] For giving an in termittent alarn when failure takes place in a controlling circuit, the cir cuits of both the controlling unit anc the alarm include a thermal switch. As shown, when current flows through the thermal unit, the contacts d are opened. Should the circuit a fail, the contacts d close and complete the alarm circuit b, the thermal device acting as an interrupter to complete the alarm circuit intermittently.