Hi!

Its quite possibly normal for the coil to get quite hot !

I'm beginning to think that it must be. It is definitely a coil rated for
use with AC power.

I talked to an HVAC guy and asked what he thought the other day in the
grocery store. He wasn't sure how hot the contactors ran, but he did raise a
good point. In this thing's normal application, it would have received some
"relief" (if you will) from the circulating fan in the equipment. I hadn't
thought of that, but it makes sense.

In any event, I put an inline meter on the power wiring going into the
transformer. With the contactor closed, the transformer is pulling about 7.2
watts at 125 volts AC.

What I've finally decided to do is to add a fuse to the transformer. It's a
3 amp slow-blow fuse (hey, it was handy!) from my parts box, but it should
stop any gross meltdowns before they happen.

The coil runs silently when powered, with no humming or chattering at all.

William