Patent ID: 7957112

Claim:
A protection circuit for limiting operating power of an electrical device, in a circuit connected to an electrical power source, to below a predetermined power rating, the protection circuit comprising: a switching device for adjusting electrical power supplied from the power source to the electrical device; a sensor for sensing a parameter relating to the operating power of the electrical device; and a comparator for comparing the parameter sensed by the sensor to identify an undesirable operating condition in which the electrical device operates at a power exceeding the predetermined power rating and for, in response to identifying an undesirable operating condition, providing an output signal for controlling the switching device to adjust the electrical power supplied to the electrical device to below the predetermined power rating, while maintaining an electrical current flow through the electrical device, wherein the switching device comprises a relay arranged to switch between first and second circuits, the first circuit providing normal connection of the electrical device to the power source, and the second circuit providing connection of the electrical device to the power source upon identifying the undesirable condition.