STATE DETECTOR FOR DETECTING OPERATING STATE OF RADIO-FREQUENCY HEATING APPARATUS

摘要

An operating state detecting technique is provided to precisely detect abnormalities of a radio-frequency heating apparatus. An anode electric current detected at anode electric current detecting resister (40) of a magnetron is input to an A/D converter terminal of a microcomputer (27) on a side of a control panel circuit board. The electric current is subjected to an analog-to digital conversion and a value of an anode voltage IaDC is obtained. The microcomputer (27) judges an operating state in accordance with a plurality of read-in values of the anode voltage IaDC. Further, the microcomputer (27) obtains the sum total of values of the anode voltage IaDC corresponding to one rotating period of rotating antennas (68), (69) and judges an operating state of the radio-frequency heating apparatus (100) in accordance with the sum total. The read-in IaDC value system set forth above corresponds to a change of a power feeding distribution and makes precise abnormality detection possible without erroneous operation. In addition, the microcomputer (27) changes a threshold value used for abnormality detection or a changing quantity (increment) from an operation start in response to a set output power when operating states, such as an output power of the radio-frequency heating apparatus, things to be heated, etc., are changed, and makes precise abnormality detection possible without erroneous operation.