| 摘要 |
PURPOSE:To enable the easy detection of disconnection of preheating plug, by providing a unit for detecting the electrical current of the plug, a unit for setting a reference value for the preheating current, and a unit for comparing the outputs of both the former units with each other. CONSTITUTION:A reference value for a preheating current is set by the reference voltage generation circuit 52 of a disconnection detecting device 5. The electrical current of preheating plugs 2 is detected by a current detector 53. A comparison circuit 55 compares the outputs of the reference voltage generation circuit 52 and a current/voltage conversion circuit 54 with each other, and finds out the difference between the compared outputs. A relay 57 or a warning unit such as a warning indication lump 58 is put in operation by an output circuit 56 depending on the difference found out by the comparison circuit 55. This constitution enables the easy detection of disconnection of eve one of the preheating plugs 2. |
