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Re: Hey Bert (or anyone else) tell me something...
In a message dated 98-08-25 03:47:53 EDT, you write:
<< ----------
From: Cabbott Sanders [SMTP:cabbott-at-cyberis-dot-net]
Sent: Monday, August 24, 1998 3:25 PM
To: Tesla List
Subject: Hey Bert (or anyone else) tell me something...
I have a 15 kva pig, and i got a 250 amp arc welder hooked in series with
it, up to 240 VAC. I have yet to feed this scarry arrangement any juice.
the dial is suppose to regulate the current.... right? the dials readings
start at 40A and go up to 250A. should i be disregarding this? i would think
the current limiting will be much different. how would i know what the
actual current is if i plug it in, with the dial at a minimum? I need a
current meter shunt thing right?
>>
Cabbott,
I definitely suggest that you use some resistive ballast in series with the
welder - at least until you get the system running and well tuned. Then you
can experiment with different ballast combinations. You connect the welder
primary (AC) leads in series with the pole pig feed lines. Then short the AC
outputs of the welder. Now varying the welder settings will control the pole
pig primary current. You should get a current transformer and meter so you
can monitor the primary AC current into the pig.
For resistive ballast, I used about seven 2,000 watt oven elements bought from
a local store such as Goodwill in the old appliance section. I set mine up so
one element was always in series with the inductive ballast. Then used a
switch array to be able to add more elements in parallel with the first to
eventually have all seven in parallel. This allowed a variable resistance
from 22 ohms to 3.3 ohms.
If you use resistive ballast, you could use a voltmeter across the resistor
calibrated to convert the voltage readings to current - in place of the
current transformer.
Ed Sonderman