Melting 2 lbs copper scrap with home made feedback induction heater
This secondary feedback induction heater uses a simple modification of the technology that runs solid state Tesla coils. The heater shown here has been run up to almost 9kW and resonates at 50kHz. The cap bank consists of 4 x 80A 3kV AC resonant caps (dawncaps). The basic schematic is shown here:
https://autotuningmainsinductionheate...
The UCC mosfet driver chips shown in this schematic were replaced with more powerful heatsinked driver chips to drive the full bridge of SKMGB100 half bridge modules in continuous resonant mode. The non heatsinked UCC driver chips would overheat and fail under these conditions. The replacement chips driving the gates on the SKM100s at 15V (plus minus 30V) are the IXDI614CI and IXDN614CI inverting and non inverting driver chips set as a push- pull arrangement.
Here is the principle of operation:
Circuit uses full bridge SKM100GB. Uses 555 set just above resonant frequency of tank circuit to start off the resonant tank. The output of the full bridge inverter is magnetically coupled to tank circuit via a ferrite coupling transformer (the thing wound with Litz wire). When this is impedance matched with the tank circuit, then there is virtually 100% energy transfer from the full bridge to the tank circuit. The coupling transformer stays cold or at most gets slightly warm. The feedback is achieved using a small shunt to one leg of the work coil- basically a thin piece of wire connected parallel to one of the legs of the work coil- this is passed through a small ferrite core wound with 100 turns magnet wire which is shorted across a 56 Ohm 5-10W burden resistor. This small coil completes the feedback loop. Opposing 5W 9V zeners are key for it to work. If they are not there then the setup will not work. Instead the low amplitude output of the 555 shorts out through the 100 turn feedback coil and parallel burden resistor and there is no signal available for the hex inverter to start off the oscillations of the bridge to kick the system into resonant mode. These opposing zeners allow the circuit to start up and run stable once enough current is fed into the system fir the feedback loop to take over.
Watch video Melting 2 lbs copper scrap with home made feedback induction heater online without registration, duration hours minute second in high quality. This video was added by user SciTubeHD 16 February 2022, don't forget to share it with your friends and acquaintances, it has been viewed on our site 55,523 once and liked it 1 thousand people.