On Jun 24, 2:17 pm, "Pete C." wrote:
Ignoramus19021 wrote:

I have not used my phase converter in a while. When I fired it up the
other day, the main Allen Bradley size 2 starter made a very loud
noise, like a old style 60 Hz door buzzer. Despite that, the converter
ran, but I decided to not use it and investigate.

This is a Size 2 starter starting a 10 HP motor.

So.

What would be the proper troubleshooting procedure here and what is
likely wrong? Any ideas?

Spiders...

As in a spider or similar bug in the contactor keeping it from fully
seating so it buzzes, but still seating far enough so the contacts
close.

Reminds me of an issue last fall. Corn dryer main blower starter was
doing about the same thing. It would fire and just buzz (this one
wouldn't start the blower). Turned out that there must have been an
Asian beetle under the contacts the first time. Smashed him good, and
it was just hammering on the contacts trying to make a good
connection. It couldn't draw enough juice through the remaining pole
to start the motor, so eventually it would pop the breaker.

Had something similar happen on the pressure pump for the house
water. It's starting to become standard practice for debugging to
check for bugs...

JW