Message-ID: <56D0C373.1090004@abelian.org>
Date: Fri, 26 Feb 2016 21:28:19 +0000
From: Paul Nicholson <vlf0403@abelian.org>
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Subject: Re: LF: MF: EbNaut
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Status: O


Thanks Wolf,  I went to low power around 20:44 and
turned off a few seconds before 20:50.

Gary wrote:

 > Solid & clean signal up to 2020z then started seeing
 > little spikes on the trace

The little spikes are from the EbNaut BPSK.  Also I was
winding the power up and down and measuring things so
it wasn't such a steady signal.

But it still isn't running right.  Oddly now with the
rewound transformer, the FETs are getting hotter, they
were pretty cool before.  Drain current is about the
same at full power.

And the transformer is still getting too hot.   Doesn't
look fit for a long run at the moment. The waveforms
look good, plenty of sharp edged gate drive, not much
ringing on the drains.  But it just isn't very efficient.

Without a load, drain current is 1.8 amps after the
rewind. Before, the unloaded current was 400mA, so something
is wrong. Full power is 5 amps at 32 volts.

I find that to get the leakage inductance down low enough
the secondary has to be wound on top of the bifilar
primary.  Is that normal?   If I space the turns neatly
around the toroid, the leakage inductance is way too
high.

I think I won't try again tonight, more work tomorrow
into the dummy load I think.

Thanks for the reports!

--
Paul Nicholson
--