High frequency heating system with changing function for rated consumption power

A high frequency heating apparatus comprising:

• a high frequency heating source having a predetermined maximum rated high frequency output;
• inverter means for receiving an AC input and supplying a predetermined high frequency drive power to said high frequency heating source, said inverter means including rectifying means for rectifying the AC input and a switching element for switching a DC output from said rectifying means;
• changing means for manually changing and outputting a plurality of rated consumption power change signals, said changing means including at least two levels corresponding to the maximum rated high frequency output of said high frequency heating source and at least one high frequency output lower than the maximum rated high frequency output, associated with a rated consumption power of said apparatus;
• and
• control means for controlling the high frequency drive power from said inverter means in accordance with the rated consumption change signal from said changing means, the high frequency output from said high frequency heating source and the rating consumption power of said apparatus being linearly, variably set in accordance with the rated consumption power change signal, said control means including an AC input detecting means for detecting the AC input to said inverter means, comparing means for comparing a detection output from said AC input detecting means with a reference signal, control signal output means for outputting a control signal for switching said switching element of said inverter means in accordance with an output from said comparing means, and reference signal generating means for generating the reference signal;
• and
• wherein said changing means changes the level of the reference signal corresponding to one of the plurality of rated consumption power change signals and said changing means further including a plurality of resistors interlocked with said reference signal generating means and a switch for switching the plurality of resistors.