| 摘要 |
PURPOSE:To safely use a heating body by blocking the electric power supply to another heating body even when the secondly mentioned heating body is in trouble by leak, etc., by using both a switch and two-way thyristor and cutting off both terminals of the heating bodies from an AC power source. CONSTITUTION:When power supply is set by rotating a rotary volume 16, an interlocked switch 19 is closed and one terminal of a heating body 4 is connected with an AC power source 2. Simultaneously, a switch 17 for signal is closed and power supply is set. The set value of power supplying rate by the position of the volume 16 is transmitted to a microcomputer 7 after the electric potential at the connecting point of a resistance 15 and volume 16 is changed and AD-converted. Upon receiving the signal, the computer determines the power supplying rate and the rate is displayed by a display means 8 and, at the same time, the power supply to the heating body 4 is controlled by sending a control signal to a driving means 9 and driving a two-way thyristor 10. The same operation is performed at another heating body 5 independently from the heating body 4. |
