GB582715A - Improvements in or relating to protective systems for x-ray apparatus - Google Patents

Abstract

582,715. Control systems for space discharge apparatus. WESTINGHOUSE ELECTRIC INTERNATIONAL CO. July 5, 1943, No. 10902. Convention date, July 7, 1942. [Class 38 (iv)] . To prevent overloading of an X-ray tube 22, supplied through transformers 12, 20 and rectifier 23, a protective relay 31, energized by voltages VKV and Vt, which are in series and dependent, respectively, upon the proposed input voltage to transformer 20 and the setting of the exposure timer 27, is adapted to open the timer supply circuit at contacts 30, and thus prevent closure of a timer relay 25 in the primary circuit of transformer 20, when the voltages VKV and Vt correspond to overload conditions. Voltage Vt is derived from a potentiometer 34 which is supplied by a transformer 36 from mains 10 and the moving contact 35 of which is connected mechanically to the pointer 28 of the timer so as to move with the latter. The potentiometer may be graded to compensate for the non-linear anode voltagetime rating characteristics of the tube, whereby all incipient overload conditions produce the same actuating voltage for the protective relay.