Re: SSTC problems1 (no its not a PlasmaSonic ;-))

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

Original poster: dhmccauley-at-spacecatlighting-dot-com 


There is a simple test, yes.  If your FETs aren't getting the drive
necessary to saturate them, then they will be running in linear mode.
If this is the case, those FETs will likely be so hot they will be glowing.

Do you have a break-out point?  You *do* need a break-out point.

 > Hi,
 > Today I finished my Feedback SSTC, It is based on Aaron and Justin's
 > feedback SSTC design, I am using a full bridge of FDH44N20 MOSFETS and a
 > 18X 4.25" secondary wound with 30AWG.  After getting much help from Steve
 > Ward via email, I finnaly got to the first testing phase.  I tuned the
 > potentiometers right in the reigon that I saw the biggest swing on the
 > scope.  I had a neon bulb attatched to the breakout point, and at about
10v
 > input, the neon bulb striked.  I brought it up to 150v and the neon bulb
 > got very bright and I coul hear 60hz buzzing in the bridge.  Now I though,
 > well I'll reverse the primary turns.  So I reversed the primary turns, and
 > STILL the output was the SAME the neon bulb was lighting to the same
level,
 > no increase and no breakout.  I am afriad my MOSFETs aren't being driven
 > into saturation by my gate driving circiutry.  Is there a way to test if
 > the MOSFETS are saturating?  Has anyone else experienced this and knows
the
 > remedy?  Help!
 >
 > Regards - Jim Mitchell
 >
 >
 >
 >
 >