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Re: ASRSG question

Original poster: "Gerald  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>

Hi David,

Seems like a 15KVA pig should charge OK. Cres for 15KVA ballast should be 192 nf so you are operating very close to resonance (.2 uf) or STR mode with .1 uf. I think someone said that the arc welder would ballast at about 30 amps of 240Vac (or 7.2KVA). If this is true, you would be only able to charge half of the capacitance as with full power. In either case (full or half power), 0.2 uf or 0.1 uf would be close to resonance. Did you bring up the ASRG to speed before powering the pig. If not, maybe resonant rise killed the caps. I'm just thinking out loud here. I have no experience with PIGs yet. If you could scope the primary (using HV probes) maybe something could be learned. How low of RPM do you estimate you went?

Gerry R

Original poster: "David Rieben" <drieben@xxxxxxxxxxxxxxx>

I tried both .1 uFd and .2 uFd. .2 uFd is a pretty big capacitance,
I know, but the 3500 rpm is the MAX rpm rating of the motor
and I wasn't running it at its max rpm. The rsg motor is a DC
with infinite speed control via a variac but I can't really tell ex-
actly what rpm I'm running. I can only aproximate it by measuring
the input voltage and multiplying the product of the input volt-
age/130 since 130 VDC is the rated voltage of the motor. I
figured the 15 kVA pig can charge even a pretty large primary
cap pretty fast although I haven't done the exact math on this
with JAVATC yet.

The pig is ballasted with a the guts of a 225 Lincoln arc welder
set at its maximum (225 amp) weldeing setting and I am using
(2) .1 uFd, 50 kV Hipotronics pulse caps for either .1 uFd
byt using just one, or .2 uFd buy paralleling them.


----- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Monday, April 04, 2005 11:58 PM
Subject: Re: ASRSG question

Original poster: "Gerald  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>


One idea that crossed my mind is that your 1/4 inch electrode gap may be part of the problem.
At 3500rpm and 8 electodes, you will have 467 pps. I dont know what size of Cap you are using but maybe at 467pps, the cap cant be charged high enough to break across a 1/4 in gap. Does it run at a lower rpm. Try 240pps. I would not go down to 120 pps with an ARSG since the phase may accidently linger at zero cross over and this could cause an uncontrolled voltage rise if any of the ferromagnetics start to saturate. If you electrically connect all rotor electrodes together, you will be able to go to two static electrodes and reduce the total gap distance to 1/8 inch.

What is the PIG ballasted at and what is your Cp value?

Gerry R.

Original poster: "David Rieben" <drieben@xxxxxxxxxxxxxxx>

No, I'm using 8 rotary electrodes driven on a 11 1/2" diameter x 1/2" electrical grade fiberglass disc. The motor is a variable speed 0 - 130 VDC, 2.5 HP treadmill duty motor that is rated at 3500 rpm.