| 摘要 |
PROBLEM TO BE SOLVED: An overcurrent protection circuit is not made to actuate at a starting current at the time of initiating the supply of electricity, and the overcurrent protection circuit is made to actuate in case an excessive current is flowing at a stationary time to prevent from an indoor current breaker being actuated, and in case such a failure has happened to occur as an excessive current equivalent to a load short circuit flows at the constant voltage power, the overcurrent protection circuit is immediately made to actuate to prevent a secondary breakdown of element. SOLUTION: This has a throw-up means by which the output voltage to a constant voltage power supply 33 is initiated to supply a predetermined voltage to a halogen heater 1 and an overcurrent protection circuit or the like that has plural actuating current values to detect a current to the constant voltage power supply 33 and cuts off a supply electricity to the constant voltage power supply 33 at the time of abnormality, and time constants Ts1, Ts2 until detecting the abnormal current of the overcurrent protection circuit are set up at a longer time than the throw up time (throw start time constant Tsu) in case an actuating current is lower (time constant Ts2) than an overshoot current value at the time of heater lighting, and they are set up at a shorter time than the throw up time (throw start time constant Tsu) in case an actuating current is higher (time constant Ts1) than an over shoot current value at the time of heater lighting.
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