loud humming from auto transfer switch. normal?

[43D18]

So after hooking up our GT351 to 50a service I noticed a very loud humming from the auto transfer switch. Everything worked fine but the humming persisted. I unplugged and replugged and the humming stopped.

Thoughts?

[Iggy]

I'm a electrician and have heard contactors do this now and then.
I suspect the bouncing around may have made the contactor out of alignment and when you energized it stayed a little cockeyed.
By de-energizing and re-energizing it seems to have realigned ok.
Nothing to worry about unless it happens every time you hookup.
I doubt it will happen again.

[43D18]

Thx Iggy. All is working fine, and was even with the humming, just seemed much louder than I would think is normal. Appreciate thw reply. I'll update with any changes.

Thx

Mike