Re: Soft transformer turn on without a variac

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

Original poster: Esondrmn-at-aol-dot-com 

In a message dated 10/29/03 11:42:02 AM Pacific Standard Time, 
tesla-at-pupman-dot-com writes:


>Anyone remember this discussion?  Basically, the
> > problem I want to
> > solve, and that was discussed previously, was how to turn on
> > power to a
> > variac without tripping breakers.  For my own setup, I have a variac
> > rated 50 amps 240 volts fed from a 30 amp 240 household line (electric
> > clothes dryer).  I set the variac at half way to step down to
> > 120.  I'm
> > using 3 (soon 4) unmodified 15/60 Franceformers.
> >
> >     What I'm looking for, if anyone can help me with this,
> > is a cut and
> > dried plan using readily available parts (part numbers & sources would
> > be ideal), a la Terry's NST Protection filter - just
> > something so I can
> > turn on power to the variac (turned down to the low end) without
> > tripping the house breakers.  Right now I'm using a big old knife
> > switch, which more often than not trips the breaker.
> >
> >     I suspect many other novice coilers could benefit from
> > a solution to
> > this too.
> >
> >     Thanks,
> >     Bill V.


Bill,

Kind of low tech, but someone on the list mentioned before to wire a light 
bulb in series with the variac primary with a switch across the light 
bulb.  Turn the system on with the switch open, the light bulb absorbs 
inrush and magnetizing current, then close the switch for full power.  You 
may need a high wattage bulb like a 1,000 watt heat lamp.  Of course, you 
could also use a high power resistor, oven element, etc.

Ed Sonderman