| 摘要 |
PROBLEM TO BE SOLVED: To provide a heater disconnection detecting device which can detect surely the disconnection of a heater out of a plurality of parallel heaters even in the case of an operation at a low voltage lower than a specified voltage of the heater and can be generally used for a variety of heaters. SOLUTION: The heater disconnection detecting device is composed of an electric heater circuit connected with a transformer and a current detector. A voltage impressed on a heater is detected by a transformer and inputted as a heater voltage signal, and a voltage flowing in the heater is detected by the current detector and inputted as a heater current signal, and in the case a relation of the signals is deviated from a predetermined region, an alarm is outputted. The device is provided with a circuit holding a maximum value signal of the heater voltage signal and the heater current signal, and constructed so that an operation for resetting a circuit that holds a maximum value signal is repeated succeeding to the finish of the take-in processing of the maximum value signal by a singal processing part, and the determination of heater disconnection is made from a relation of the maximum value of the heater voltage signal and the maximum value of the heater current signal. COPYRIGHT: (C)2007,JPO&INPIT
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