Re: 4.5amp Variac good enough?

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

Original poster: "Terry Fritz" <twftesla-at-uswest-dot-net>

Hi Matt,

A 12000volt 30mA transformer can be rated in "VoltAmps" or "VA" which is the
measure used for such things.  You simply multiply the voltage and current.  so
your transformer is:

12000 x 0.030 = 360 VA

Your variac is the same idea so:

120 x 4.5 = 540 VA

So the variac has plenty of room to spare.  You will want about 90uF for a PFC
cap.  However, from the chart below, your tranny would run about 550 VA without
a PFC cap so you would still be close to fine.

http://hot-streamer-dot-com/TeslaCoils/Misc/NSTStudy/12-30.gif

You may note that variacs can be run at higher than recomended power too for a
short time as shown in figure "F" below.  A little fan helps a bunch too.

http://hot-streamer-dot-com/TeslaCoils/Misc/VarBack.jpg

However, it is always best to run things within their ratings if you can...

Cheers,

        Terry


At 09:14 PM 2/25/2001 -0500, you wrote: 
>
> Hi,I have a 4.5amp variac and wondered if a PFC capacitor used with a 
> 12kv30ma NST could be fed by the 4.5amp variac? 
>
> matt