| 摘要 |
PROBLEM TO BE SOLVED: To provide an electric heater capable of reducing a leakage current from a sheathed heater by using a means arranged essentially for an apparatus. SOLUTION: A safety relay 16 which interrupts electric power supply to the sheathed heater 2 when an apparatus temperature is abnormal is installed separately from an SSR 10 controlling a power supply quantity by turning on/off power supply to the sheathed heater 2 when intermediate potential is connected to an alternating current power supply 1 connected to the ground. By a relay failure detection circuit 17 detecting a failure of the relay 16, electric leakage by an insulation failure of the sheathed heater 2 is detected, and when the failure is detected, the relay 16 and the SSR 10 are turned off to reduce the leakage current from the sheathed heater 2. COPYRIGHT: (C)2010,JPO&INPIT
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