Re: 10amp Hump

From: 	Robert W. Stephens[SMTP:rwstephens-at-headwaters-dot-com]
Sent: 	Sunday, June 22, 1997 9:07 PM
To: 	Tesla List
Subject: 	Re: 10amp Hump

> From: 	George W. Ensley[SMTP:erc-at-coastalnet-dot-com]
> Sent: 	Friday, June 20, 1997 12:40 PM
> To: 	tesla-at-pupman-dot-com
> Subject: 	10amp Hump
> All,
> I got my new 5KVA pig from T&R this week. EXCELLENT SERVICE!
> Ordered it on Friday got it on Wednesday. Boy is it big 250 lbs and almost
> as tall as my wife.
> Only having a 110v variac i am driving 1/2 the pigs primary. The welder is in 
> series, with a couple of 1500w heater elements across the welders  primary.
> What is interesting is that i see a 10amp hump in current as i bring the voltage
> up before the gaps fire, no load. The hump is reduced by the heaters and
> when the gaps fire the current goes up as expected but seems excessive for
> the results produced by the TC. Any suggestions?
> George.......

Sounds like your pig might be leaping into 60 Hz resonance once some 
mid value of variac setting is reached.  If this is true, further increases in 
the variac setting will not appreciabley increase the HV output of the 
pig.  Rather than risk life and limb poking around on the HV side of 
the pig, an easy and safe way to confirm this would be to install a 120 
volt 60-100 watt incandescent lamp across the other 120 volt primary 
winding of the pig.  If the pig *is* snapping into resonant 
saturation that 120 volt lamp will make a sudden leap from very dim 
to somewhat brighter than normal for its rating (it may suddenly have 
~170 volts AC going to it).  Let us know what this simple test shows.