GB190612333A - Improvements in or relating to Apparatus for the Electrical Production of Heat for Cooking and other purposes. - Google Patents

Abstract

12,333. Berry, A. F. May 26. Transformers. - In electric heating- apparatus of the induced - current type, the part of the permanentlyclosed secondary circuit which lies outside the core is so constructed that the induced current passes back to the portion inside the core along a path practically parallel with and close to that which it takes on leaving, thus minimizing wasteful induction effects. The primary circuit 2 is wound round the central member 1<a> of the core 1. Outside this is wound a single turn 4 of the secondary conductor, the two ends of which are connected to two metal strips 4<a>, 4<b> electrically connected to a circular plate 6, serving as a support for the article to be heated. The plate has a slot 6<c>, so that the inductive effect of the current passing thus in practically parallel parts is greatly minimized. The slots 6<b> cause the current to pass through the central portion 6<a> of the plate, which is recessed so as to present a smaller sectional area to increase the heating effect. The slots may be in other directions to effect these purposes. In a modification, the secondary circuit 4 is formed in two parts, both of which have strips 4<a>, 4b for connexion to the hot plate. In this case, a slot may extend across the hot plate so that the adjacent portions of it carry current from the two parts of the secondary circuit in opposite directions at the same time. In another form, the heating-portion is formed of two superposed plates insulated from one another except at one end, the upper of which may be slotted, the current passing from one plate to the other.