Re: estimating voltage from HV transformer

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

Original poster: "Dr. Resonance" <resonance-at-jvlnet-dot-com> 



6-8 kVA would be a very safe value to use for 30 to 60 sec operations.

At this high of a potential you would certainly want to replace the xmfr
with fresh oil before operating.
A local power utility repair group could also do a standard 30 kV Erms "cup
test" on your xmfr oil with a 1 pint sample.  Most medium size utilities
have a field portable cup test unit.

The oil is poured in and then it's brought up to 30 kV for a specified
period of time.  If breakdown occurs the oil is rejected and fresh oil is
required prior to operation, or, with an operating xmfr system, some
downtime is routinely scheduled for the draining and refilling of the xmfr.

Dr. Resonance


 > I know this is pretty basic stuff but I was hoping some
 > of you could give me some insight into this situation. I
 > have a 140 kVP, 500 mA single phase Picker x-ray
 > transformer that I have removed the diode sticks from
 > and am running it AC to power a wicked Jacob' ladder.
 > Anywho, I was wanting to get a pretty good ball-park
 > estimate on the actual AC voltage that it puts out with
 > a given input voltage from the variac input. I know that
 > the basic rating of an x-ray trannie is for very short du-
 > ration and that their ratings have to be considerably
 > downgraded for cont. operation. The name plate on
 > mine says that it's only good for 3.6 kVA continuous
 > output but I'm sure that this means w/out the diodes
 > removed  and as a DC power supply. The transformer
 > itself is a monsterous 980 lb. 22" tall x 22" wide x 36"
 > long oil-filled steel tank. The tank holds 62 gallons of
 > transformer oil (est 400 lbs of oil).

 > Keep 'em sparkin'
 > David Rieben