| 摘要 |
PROBLEM TO BE SOLVED: To break operating power to an electric device in an overheating state by providing a safety device equipped with a conductor element thermally close to at least one among plural circuit elements of the electric device energized through operating power. SOLUTION: The main portion of a safety circuit 37 is contained in a controller, is connected to a power source via a fuse 38, and overcurrent is protected by the fuse 38 so that the circuit is broken. When an on-off switch 18, a relay switch 44, and a bimetal thermostat 48 are closed, a heating element 12 is energized so as to generate heat by passing current via resistive PTC material 26 between conductors 28, 30. The heating element 12 contains a conductive element or a fiber 34, and is connected to operating power, and is extended along the whole length of the heating element 12 from a point 58 to a point 60. The conductive fiber 34 electrically insulated from the PTC material 26, and the conductors 28, 30 is connected to a relay coil so as to cause current to flow. |
