In a message dated 25/05/2004 22:01:42 Central Europe Standard Time,
[email protected] writes:
Maybe somebody has something to say about
this......
I think you're spending too much time measuring things at frequencies that
are not LF. It's a great analysis of the detail, but I can't help thinking you
are overlooking an obvious fault.
BTW. What is the output power? The supply Voltage? and the
efficiency?
Just concentrate on the basics. The circuit works, but if you start
removing diodes adding resistors etc, then there's not much anyone can do to
help as you are now developing your own circuit and not trying to duplicate
mine.
Build the circuit as close to the original as you can.
Check you have the correct waveforms at the gates. (keep wire lengths
short. This maybe 136kHz, but the waveform rise and fall time neeed to be fast.
Around the HEF4013, FET driver and FETs, the construction should be consistent
with good VHF practice )
Measure the 136kHz output power, the supply voltage and calculate
efficiency.
Then you'll have a benchmark of performance. If you have less than 200W
output from a 36V supply or an efficiency less than 60% then you have a fault in
a component or in the construction that you need to find.
After you have a reasonable benchmark, change one thing at a time and
compare. If you have an improvement, leave it in circuit. If you don't, then put
it back as before and try something else. Jim's work on the transformer is
excellent and I'm now comparing my original transformer with a version of Jim's
built on a 3C90 42mm core as supplied in the kit.
I've built versions of this circuit from 400W at 73k to 700W (4 FETs) at
136kHz. There's even a version running in the Medium waveband around
1200kHz.
Good luck
David G0MRF
