Re: Halogen SMPS

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

Original poster: Jan Wagner <jwagner-at-cc.hut.fi> 


On Sat, 3 Jan 2004, Tesla list wrote:
 > Original poster: Kreso Bukvic <kreso.bukvic-at-kc.htnet.hr>
 >
 > I yesterday looked at halogen smps rated for 150 W. They are expensive like
 > heck but could they power a SSTC ? Maybe 2 in parallel?

If you have a look inside, it's just a high freq oscillator on the mains
side that drives some power transistors, which in turn drive a small
toroidal ferrite core transformer. In the cheap models I got, the output
isn't even rectified. It's 12V or thereabouts, which means that to make
it useful for TC use you'll have to remove the original secondary and add
a new one with 100..200 or more turns to get HV.

The nice thing with the xfmrs in the halogen smps is that the pri and sec
have a thick plastic spacer ring in between them, so insulation is
already quite good "per default". A HV-modified smps might work quite
well even with no extra insulation. But I'd nevertheless dip the modded
xfmr into polyurethane varnish or some crafts shop casting resin to help
the HV corona and flashover risk a bit...

I've been too lazy to measure yet what freq these things run at - could be
100kHz. The other thing is how stable that freq is with respect to the
load - i.e. whether or not this smps is suitable for a direct base-feed
of the TC secondary coil. Without knowing, the safest thing would be to
rectify the HV AC output of the modded smps, and feed it to a traditional
TC setup with spark gap & tank cap etc.

Just my $0.02...

regards,
  - Jan

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  Helsinki University of Technology
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