PURPOSE: To detect an abnormal temperature rise generated in a part even when there is no current difference on normal operation and on abnormality, to detect the fault of an electrical equipment, to interrupt the power circuit of the equipment and to protect the electrical equipment by composing a protective gear of a temperature sensor, an input interface, a micro-computer and the power circuit of the electrical equipment.

CONSTITUTION: A temperature sensor 11 detects the abnormal temperature rise of a part generated at the time of the fault of an equipment, converts the temperature rise into the quantity of electricity and adds it to an input interface 12. The input interface 12 converts the quantity of electricity into a signal capable of being input to a micro-computer, and adds the signal to the micro-computer 6. The micro-computer 6 outputs a control signal when the signal input from the input interface 12 is turned into a specified signal, and adds the control signal to a relay circuit 7. The relay circuit 7 interrupts the power circuit 8 of an electrical equipment. Accordingly, the abnormal temperature rise generated in the part is detected, the power circuit of the equipment is interrupted, and the electrical equipment can be protected.