[AMPS] SB220 Xformer labodomy

[Steve Thompson]

In message <19990220134450.AAA11963@[209.239.238.77]>, Rich Measures
<measures@vc.net> writes
>
>
>>
>>In message <19990218225337.AAA20049@[209.239.238.103]>, Rich Measures
>><measures@vc.net> writes
>>>
>>>
>>>
>>>>
>>>>I have a very noisy SB220 power transformer that sounds like a bad
>>>>florescent ballast. Other than being noisy, the amp works fine.
>>>
>>>€  Such transformers are normally potted in tar.   However, you could
>>>have one with a potting void.  .  On my Web site, a simple method of
>>>potting transformers with polyester laminating resin is described.  The
>>>transformer needs to be removed in order to do the potting.  The screws
>>>that hold the laminations together need to be tightened before potting.
>>>
>>>-  later, Len
>>
>>Yacht varnish appears to work well. We submerged the tfr for 24hrs and
>>let it dry for a week or so.
>>
>€  I like to use such varnish for the outside of the laminations.
>However,  shrinkage during drying  is so large that is it not appropriate
>for use inside a transformer.  .  Polyester laminating resin does not
>have this disadvantage.
>
>-  later, Steve
>
Good point - our need was only external protection.

Steve

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