Patent ID: 7772530
Filing Date: 2010-08-10
Classification: H05B

Abstract:
1. Apparatus for induction heating of a workpiece, the apparatus comprising: a power source having an ac output with pulse width modulation control; an impedance matching device having an input connected to the ac output of the power supply; an inductor connected to the output of the impedance matching device to generate an ac magnetic field; a means for moving the workpiece through the inductor to magnetically couple selected parts of the workpiece with the magnetic field; a means for selectively adjusting the frequency of the ac output when each one of the selected parts is coupled with the magnetic field for induction heat treatment; and a means for selectively adjusting the power of the ac output by changing the duty cycle of the ac output when each one of the selected parts is coupled with the magnetic field for induction heat treatment and the frequency of the ac output is adjusted.