Re: De-Rating '400hz' Variacs

In a message dated 96-05-11 01:49:31 EDT, you write:

>The problem is,
>>how much should I de-rate a 60Hz variac when used in 50Hz service? 
>Technically, 50/60 of voltage. Now for 400Hz to 50Hz that is
>significant, for 60Hz to 50Hz: don't worry about it.

I just recently came upon a couple 3 phase 10a 120v variacs. Problem they are
400hz. Are they of any use, can you derate these?

Kevin M. Conkey

  I asked the same question a while back and got the answer of 60/400 or 18 volts.
  Even so, I bought one and took it apart.  Talk about nicely wound toroidal chokes.
  I took the thing apart with the intention of using the wound cores as filters.
  I'm going to cover mine in epoxy for insulation.  They should work quite well for
  400Hz and higher frequencies.
  -- Chip