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Registered Member #75
Joined: Thu Feb 09 2006, 09:30AM
Location: Montana, USA
Posts: 711
I have seen audio transformer in guitar amplifiers etc. that use the same thickness laminations as the mains power transformer. From this I guess it is safe to say that you can go up to a few kHz without getting into too much trouble due to iron losses. I suppose it really depends on the transformer, and how hot you can tolerate it to get. Sure there will be more losses, but I would not be surprised at all if you could get 10 times the output power with only a 2 times increase in the losses.
Registered Member #1104
Joined: Tue Nov 06 2007, 07:38PM
Location: Wisconsin, United States
Posts: 34
A while ago I decided since I didn't have a fly back I would replace it with a wall transformer wired in reverse. I used a single transistor design (because it was simple) and hooked it up. The only thing I actually had to do was wind a feedback on the core because I used the original primary and secondary. Then I turned it on and I was surprised to get a 1cm arc to ground (from 6 volts in). I am guessing it was running at about 4-6 kHz. Unfortunately the secondary shorted internally after a few min.
Registered Member #1408
Joined: Fri Mar 21 2008, 03:49PM
Location: Oracle, AZ
Posts: 679
FireBird wrote ...
A while ago I decided since I didn't have a fly back I would replace it with a wall transformer wired in reverse. I used a single transistor design (because it was simple) and hooked it up. The only thing I actually had to do was wind a feedback on the core because I used the original primary and secondary. Then I turned it on and I was surprised to get a 1cm arc to ground (from 6 volts in). I am guessing it was running at about 4-6 kHz. Unfortunately the secondary shorted internally after a few min.
This is very interesting as there is such a vast difference in wall warts you MAY be on to something. I have seen (especially from Motrorola) wall transformers that were designed for higher levels (those were 16v) and they may have enough to withstand this type of reversal for more than a few minutes. Not knowing what you started with, it's difficult to say if this is really applicable but there are some, especially the older ones that have much more accessibility (larger, simpler design) especially the HP printer transformers.
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Running laminated transformers on higher frequencies
