[AMPS] Stupid transformer question
Sun, 16 Dec 2001 05:38:44 -0800
>> A quick&dirty test of the insulation might be to simply connect the
>> (fused) unloaded xfmr's primary to 220 briefly to see if it can stand
>> twice the voltage it will see when you actually use it. Then lift the
>> secondary winding from ground, ground the other end and re-test to
>> verify the insulation at both ends.
>Woah there! Don't do that!
>Most efficient transformers are designed to run with the core near
>saturation. Very few would have safety factor of 2x.
> ... ...
// Most of the transformers I've tested begin to saturate at c. 20%
overvoltage. 100% overvoltage is unreasonable. The best insulation test
is with a high-pot tester.
- To see when the core is getting near saturation, unload the
secondaries, slowly increase primary potential and watch primary current.
When pri. current begins to increase substantially, saturation is
- To improve transformer insulation, pot the transformer with
(polyester) fiberglass laminating resin. Potting can be done in one's
workshop for low cost. Info on insulation/potting is on my my Web site.
See "Amplifiers" - Part 3.
- R. L. Measures, 805.386.3734,AG6K, www.vcnet.com/measures.
FAQ on WWW: http://www.contesting.com/FAQ/amps
Administrative requests: amps-REQUEST@contesting.com