| 摘要 |
PURPOSE:To automatically dehumidify the insulating material of a heater, by providing a leakage detector outputting the signal inversely proportional to the magnitude of the leak current of the heater and a voltage controller for controlling the voltage of the heater corresponding to the signal from said leakage detector. CONSTITUTION:A leakage detector 7 detects the leak current of a heater 1 to output the signal inversely proportional to the magnitude of the leak current. For example, when the insulating material of the heater absorbs humidity and the leak current increases, the reduced signal inversely proportional to said increment is contrarily outputted to a voltage controller 8. The voltage controller 8 controls the voltage of the heater 1 corresponding to the signal from the leakage detector 7. That is, when the leak current is increased, the signal inversely proportional to this is inputted and, therefore, the voltage controller drops the voltage of the heater. When the voltage of the heater drops, the leak current of the heater is reduced and the generation of an electric leak accident is prevented and the insulating material of the heater is dehumidified by the self-generation of heat of the heater. |
