GB587953A - Improvements in electrical energy regulators for electric cookers, ovens, hot-plates and the like - Google Patents

Abstract

587,953. Switching systems for heating resistances. SHARPLES, J. T., WOOLNOUGH, G. L., and METROPOLITANVICKERS ELECTRICAL CO., Ltd. Sept. 26, 1944, Nos. 18371/44. 4048/46 (divided out of 587,947, [Group XXXVII]) and 11497/45. [Class 38 (iv)] In a supply system for a hot-plate or the like having two or more heating elements controlled by a regulator which adjusts the average current input to the elements by adjustment of the " on " and " off " periods of the current, the regulator has, in addition to a number of control settings in which the elements are connected in parallel and which proyide progressively increasing mean current input, further settings whereby the circuit of one element may be interrupted or the circuits of all the elements may be continuously closed. The regulator may be of the form described in Specifications 517,538 or 587,947, [both in Group XXXVII]. As shown, heating elements H1, H2 are supplied from lines LI, L2 through a regulator of the form illustrated in Fig. 9 of Specification 587,947 and having six control settings in addition to an " off " position. In the " off " position, contacts 5, 6 are maintained separated to open the common supply lead from line L1, whilst over the range of control settings 0-4 the elements are energized in parallel over the normally closed contacts 50, 51 of a snap action switch and the intermittently closing contacts 5, 6 of the regulator. The period of closure of the latter contacts progressively increases from setting " 0 " to setting " 4." At setting " 4.5 "contacts 5, 6 are permanently closed and the elements, therefore, continuously energized, whilst at setting " 5 " the snap action switch opens its contacts 50, 51 so that element H1 alone is energized continuously. In a modification, contacts 50, 51 open at setting " 4.5 " and reclose at " 5."