Re: Variacs - Overpowering an NST.

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

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

Hi Ed,

At 09:47 AM 2/16/2002 -0800, you wrote:
>Tesla list wrote:
>> 
>> Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>
>> 
>> Hi Neil,
>> 
>> See Figure F in this sheet:
>> 
>> http://hot-streamer-dot-com/TeslaCoils/Misc/VarBack.jpg
>> 
>> It shows how much overload current you can put through a variac and for how
>> long and then how long it needs to cool down.
>> 
>> You can overload variacs substationally (with current but NOT voltage).
>> You just have to let them cool down.  A small fan blowing on it does
>> wonders.  You do have to be very careful not to burn the brushes.
>> 
>> Cheers,
>> 
>>         Terry
>
>Terry:
>
>	That statement about overload could be taken two ways, as I well know
>from having a wife who ALWAYS makes the unexpected interpretation!!  I'm
>sure what you meant about voltage is that you can't "overvolt" an
>iron-cored device by more than a percent, rather than that there is no
>limit to the voltage you can apply to one.  [In spite of the frequent
>question about running a 120 volt transformer on 240 volts to get more
>output.]
>
>Ed
>

I meant that you can take a 10 amp variac and pull 30 amps out of it for a
short time without much worry.  However, if you take a 120 VAC variac and
plug it into 240VAC, that's "bad" ;-))

Of course, running a 120VAC variac at it full 140VAC designed output
capability is just assumed ;-)))

Cheers,

	Terry