Re: Interference-SSTC

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Jan Florian Wagner by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jwagner-at-cc.hut.fi>


> I dont think i can lower the frequency much at all.I have tried top 
> capacitance and it really gets hard to tune.That leads to QUICK MOSFET 
> heating and then its death.

When you go down in frequency, remember to add more primary turns so that
you don't overpower the mosfets!

If you are using a gate drive transformer for the mosfet drives, you
probably have to make a new drive xfmr that works at this lower frequency 
(IF the new frequency is much below the original one, AND the gate drive
waveform looks sloppy and the xfmr drive circuit starts to heat up
unnecessarily much).
 
> BTW-my old fan mysteriously died.No heating.It has surface mount ICs and 
> such.Could it have been killed from output from the secondary?

Could be. If it was one of those brushless / PC PSU type fans. They
really don't like overvoltage... A capacitor on the fan power supply lead
(as close as possible to the fan) should help here.

The cap does not help though, if your supply voltage itself goes much
beyond 12V (if it is a 12V fan). One 12V fan I "tested" died on 18V input
already. :o(

cheers,
 - jan
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