Patent ID: 7808760
Filing Date: 2010-10-05
Classification: G01J,G01K,H01H,H01R,H02H

Abstract:
1. An electrical device including a heat sensing circuit to enable a load to be selectively coupled to or disconnected from a power source in accordance with a level of a sensed temperature, the circuit comprising: a relay assembly operable between a closed state when the sensed temperature is below a predetermined limit temperature, thereby enabling the coupling of the load to the power source, and an open state when the sensed temperature is above the predetermined limit temperature, thereby electrically disconnecting the load from the power source; and a sensor assembly including a light source operatively associated with a light sensor, the light sensor being configured to be sensitive to specific levels of the sensed temperature, the light source being configured to emit light along a plurality of optical paths at any one of a plurality of wavelengths sensitive to temperature, wherein the light sensor is configured to sense temperature at any one of a plurality of operating points on the electrical device and trigger the relay assembly between the closed state and the open state.