Hello Hass,
Yes, many people have tried microwave oven transformers with varying results.
I have had good luck and bad. The biggest problem is the fact that one end
of the secondary winding is bonded to the transformer core. It is a simple
matter to lift this connection off but there is then a great risk of
insulation breakdown from the now floating ht winding to the core.
I have done this twice with home brew amp. I had one flashover and the
second try has been in service for around 8 years without incident.
You must also remove the two reluctance slugs that are wedged into the
core. Not sure what they do but you don't want them in there for your ht
supply.
A better option is to have 2 identical transformers and run the primaries
in parallel and the secondaries in series in a grounded centre tapped
configuration. This does away with the risk of the ht flashover.
There is another disadvantage with these transformers. The core laminations
are generally welded. I think that this results in increased core losses
and heating.
A friend of mine, VK6EH, actually stripped down a microwave transformer
core by grinding out the welds. He then bathed each lamination in a thin
shellac solution and reassembled the core and increased the insulation
between the secondary winding and the core. He used insulated bolts to bolt
the core together rather than welding it. After doing all this work, the
transformer runs very cool where previously, it used to get very hot even
when no current was being drawn through it.
73 and good luck,
Alek. VK6APK
At 01:52 PM 27/07/2003 -0300, PU5HAS-Emilio Hass wrote:
>Hello,
>someone here have ever tried to use transformers from microwave ovens to
>use in an amp?My friend told me that the voltage is about 2000v...Perhaps
>is a good way(and cheaper) to do an amp...
>
>
>
>73s
>Hass
>PU5HAS
>
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