Re: 400 Hz/60Hz Re: Vicious Cycle! (fwd)

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Ed Phillips by way of Terry Fritz <twftesla-at-qwest-dot-net>" <evp-at-pacbell-dot-net>

Tesla list wrote:
> 
> Original poster: "davep by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<davep-at-quik-dot-com>
> 
> > What's the difference between a 400hz Variac and a 60hz
> 
> > Variac?
> 
>         Mostly:
>         core material and core size.
> 
> > Besides the obvious!! :o)
> 
> > Can a 400hz model be used on 60hz lines?
>         Sort of.
> 
>         In general 400 Hz gear CAN be used BUT at vastly
>         reduced volatage ratings.  (roughly: the limiting
>         factor is CURRENT rating, to keep THAT the same,
>         when a 400Hz nominal design is used on 60, that means
>         applying less voltage.
> 
>         There is a 'rule of thumb' which i forget.
>         Maybe:
>                 1/2 the 400 Hz nameplate voltage at 60 Hz can
>                 be applied.
>         But i can't swear to that.
>         Hopefully someone has this factoid to hand...
> 
>         best
>         dwp

	No; way too high.  The maximum voltage to avoid core saturation would
be the 400 cycle nameplate voltage times (60/400).  In the heyday of WW2
surplus I remember some dishonest dealers selling 400 cycle motors and
transformers with the note "conservatively rated at 400 cycles".  I
suspect that more than one guy filled his shop with smoke.

Ed