[Sneap] 400 cycle transformers

[Bob Darling]

Paul
It would seem that one possibility would be a240VAC  to 12VAC 60Hz 
transformer. This would give [connected backwards] about 11400VAc at 
about the primary 240VAC rating [1A at 240VAC would be about 250VA, 
safety factor might request a 500VA transformer] If hysteresis causes a 
problem, check out some people who sell E-I laminations for grain 
oriented steel in the same size lamination. It is not an impossible task 
to swap laminations, but hard to pot, so the transformer might produce 
an objectionable amount  of 400HZ hum.This should solve the ratings. You 
might be able to boost the input voltage with a reversed 400 cycle 
variac which occasionally shows up on ebay.
If you can, however, consider operation at about 3:1 voltage rating. 
This would decrease the hysteresis losses to a better level. Then look 
at something like a 480VAC output transformer, which would give about 
1400VAC. You would need a 20VAC input [output] So you should look for a 
480 to 24VAC control transformer with a 1500VA rating. This might be 
hard to find. This would be enough cheaper to warrant the try.
Last. There are companies which will wind custom transformers as a 
prototype. Call Mike Frost at Frosrt magnetics. His one-off price might 
still be better than what you can find commercially. Just tell him it's 
a prototype which might lead to a product.
Good Luck.
Bob Darling
Retired [almost]


Jones, Paul wrote:
>
> Does anybody know a good, reasonably priced source of 400 Hz transformers ? I need both step down and step-up.
> The specific one we are using now is a 70 VAC input with 1700 VAC output for our probe voltage power supply, but we are looking for a similar secondary voltage with a capacity of 1 Amp to drive a more powerful ion source oscillator.
> Any ideas would be appreciated and should be sent to pwjones at unt.edu
> Thanks.
>
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