| 摘要 |
PURPOSE:To protect a switching element against failure in commercial AC mains and secure a cooking apparatus with safe and stable operation by decomposing the current flowing through a heater coil into digital amount of required resolution, and continuing monitoring. CONSTITUTION:An abnormal voltage is generated at commercial AC mains 9 resulting from momentary power failure, ground discharge, etc., to cause flow of excessive current through a heater coil 2, and the coil current converted by an A/D converting means 4 into digital amount with the specific resolution is turned from the specified digital amount L2 to L3. Now the output of a high frequency power supply 1 is suppressed by a control means 5, and when even the L3 is exceeded, this is stopped so as not to allow flowing of the coil current. After stopping, the power supply 1 is output for a certain period of time at certain intervals by a return means 6, and when the coil current has become under the digital amount L3, the output stop of the power supply 1 is released, and return to the normal output is made after a certain time by a return point delay means 7. |
