On Oct 29, 10:18 pm, rich wrote:

Does the coil resistance change much as the contactor wears out?
Somehow, the contactor coil seems to get weak over time, or the
contacts inside are dirty or both. My master contactor would click,
but not turn everyhing on until I cycled it a couple times.

It's the contacts inside that get oxidized or burned, not a
weakening coil. They're usually copper, and copper's oxide isn't a
good conductor so they will heat up and oxidize even faster. The
opening of the contacts creates a spark and burns them, adding more
resistance. Clicking it on and off will sometimes result in contact,
but the contactor is basically shot.

Dan