Re: electronic PWM variac

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Dmitry (father dest)" <dest@xxxxxxxxxxx>


> Original poster: Jim Lux <jimlux@xxxxxxxxxxxxx>
>>
>> >Re  "electronic variac" using a bridge rectifier and a
>> > single PWM FET.
>>
>>>If this circuit works with inductive loads, then it's
>>>only by sheer luck. There is no path for the current
>>>to free-wheel when the FET is off, so you wind up
>>>either destroying it, or having to use an oversized
>>>snubber that wastes a lot of power to keep it alive...
>>>
>>>Steve Conner


> Ah yes... but a TC with a pole pig isn't particularly inductive. At
> least, it shouldn't be.. the pole pig has fairly low leakage
> inductance.  There's not much energy stored in the capacitor charging
> part of the primary, so freewheeling might not be much of an issue.

> Driving an unloaded NST is another matter.

how about magnetizing inductance of the pig?
and how about pfc-ed nst?