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US 4,902,877 AGranted
Power control for multiple heating elements
AssigneeMicropore International Limited
InventorsAlfie L. Grasso, Richard C. Scott
Life of this patent
Estimating the term…
Abstract
A power control arrangement for controlling the power output of a plurality of resistive heating elements (9a, 9b) comprises a multi-position switch (S1, S2) for connecting the heating elements in series and in parallel, a zero voltage switch (4), AND-gate (5), clock pulse generator (6), shift register (7) and semiconductor device (8) such as a trail which cooperate to vary the duty cycle applied to the heating elements in both serial and parallel modes.
Claims4
Heating apparatus for an electric cooking appliance comprising:
- only two resistive heating elements having a fast thermal response, such as infra-red lamps;
- power source means for providing a source of alternating current;
- and
- manually operable switch means for controlling the power output of said two elements in response to energization with alternating current, said switch means comprising connecting means for selectively connecting the elements in series or in parallel, selecting means for selecting a proportion of complete half-cycles of alternating current to be blocked from energizing said elements, and blocking means for blocking the selected proportion of complete half-cycles from energizing said elements irrespective of whether said elements are connected in series or in parallel.
1 more element
Dependencies are inferred from the claim text.