| 摘要 |
PURPOSE:To completely prevent the anomalous rise of temperature in heaters by a method in which the operating current of a motor to drive an air blower is detected and according to the magnitude of the current, whether the amount of air to be sent is normal or abnormal is judged. CONSTITUTION:When making an operation switch 8, an exciting coil 4-a for a motor is excited and an air blow is actuated. The load current of the motor 1 is detected by a no-load warning circuit 9, and when the load current is greater than no-load current, the output contact 9-b of a warning circuit is closed, and the exciting coil 6-a of an electromagnetic switcher 6 for heater is excited to supply current to the heater, thereby forming an atmosphere of a given temperature. If the motor becomes no-load state or the circuit is interrupted because of overload, the situation is detected by the no-load warning circuit 9, the contact 9b is opened, electrification to the heater 2 is interrupted, and the anomalous rise of temperature is completely prevented. |
