Electric circuit for a mains electric cooker - has temperature-controlled relay to reconnect element across two phases for voltage boost, subsequently reverting to phase-neutral connection

摘要

The circuit for the heating element has a higher voltage applied initially (and occasionally afterwards) to give a faster warm-up time. At least two phases of a three phase mains supply must be available, as well as the neutral. The element is connected between one phase to neutral by a relay operated switch and between the same phase and another phase by a second switch, operated by the same relay. The relay is activated by a sensor detecting the residual heat of the element. For low temperatures, the relay connects the element between the phases, but when the element is already hot, it is connected between the phases, but when the element is already hot, it is connected between the first phase and neutral. ADVANTAGE - No need for temp.-dependent resistors to control current in element.