"Jon Elson" wrote in message
...

No, this is totally normal for control transformers
on a 3-phase supply.

Thanks!! That's really what I was asking about. It's just not a situation
I've needed to work on before.

But, where does your 3 phase power come from?
Is this an industrial location with utility 3-phase, or are you using
a "phase converter" in your garage?

It's an industrial situation, a welding & fabrication business with real
3-phase power.

You can measure the DC resistance of the contactor coil, but that does not
indicate the AC load. Due to inductance,

I understand that, but often a resistance value is good enough to determine
whether the contactor's coil might be shorted. If I knew the expected
resistance I could at least have a starting point for troubleshooting since
resistance is much easier to test.

Since the thing still works, connect a meter in the secondary circuit and
read the current with the contactor turned on. Then, get a transformer to
suit.

The secondary is fused at 1-amp and this is supposed to be a 4-amp
transformer so Im not too concerned about that part of it.

I'm more concerned with the primary current because the primary of the
original (bad) transformer is open. I didn't check that before and was
expecting the secondary to be open instead. The problem with the new
transformer seems to be on the primary since it's happening even without a
load connected to the secondary. At this point I'm pretty much convinced
the new transformer was faulty.

I wish I'd measured the current draw on the primary but at this point I'm
figuring it's too late. Since it's smoking it's probably already somewhat
shorted and drawing far more current that it normally would.
At any rate, my next move is to contact mpja.com and see if they'll replace
it. If not I'll get one from a local appliance parts dealer which I
probably should have done in the first place. They show a 35VA transformer
for $18.95 and a 40VA version for $25.50. Either way I'll be sure to check
several things before I pull the trigger next time.

I may still try and check the secondary current first though.