Hi All
I've wanting to build a induction heater, but not winning much with it.
The problem is as soon as I power it up, it either blows the fuse (10 Amp) or pops the Mosfets.
I have attached the schem of the circuit used.
I have tried various mosfets (IRF540, IRFZ44N, IRFP460) all the same.
However if I only power up the +15V (LM7815) side and place my scopes probes onto the gates, I can see its oscillating, at roughly 120khz if I recall correctly, however the waveform doesn't appear to be correct, and it would appear that the gates are both high for a fraction of a second, and the voltage levels seem to be funny, with low only going down to 2.2V and high only going to 3.8V.
+24V is from a rectified Toroidal transformer with a 15000uF cap. rated for 10amp.
The work coil is 8 turns of 4mm copper tubing, the coil is 60mm diameter and 55mm long. It is centre tapped to form 4+4 turns.
I've tried various arrays of capacitors for C1 (22nF to 4uF), but it still won't start up and keeps popping fuses etc.
Any assistance would be greatly appreciate!
Thanks in advance
Justin
I've wanting to build a induction heater, but not winning much with it.
The problem is as soon as I power it up, it either blows the fuse (10 Amp) or pops the Mosfets.
I have attached the schem of the circuit used.
I have tried various mosfets (IRF540, IRFZ44N, IRFP460) all the same.
However if I only power up the +15V (LM7815) side and place my scopes probes onto the gates, I can see its oscillating, at roughly 120khz if I recall correctly, however the waveform doesn't appear to be correct, and it would appear that the gates are both high for a fraction of a second, and the voltage levels seem to be funny, with low only going down to 2.2V and high only going to 3.8V.
+24V is from a rectified Toroidal transformer with a 15000uF cap. rated for 10amp.
The work coil is 8 turns of 4mm copper tubing, the coil is 60mm diameter and 55mm long. It is centre tapped to form 4+4 turns.
I've tried various arrays of capacitors for C1 (22nF to 4uF), but it still won't start up and keeps popping fuses etc.
Any assistance would be greatly appreciate!
Thanks in advance
Justin