In article ,
says...

snip

I have access to the unit and can get the HVAC guys to work on it
but maybe some hints will save us some hours/days of experimenting.
Thank you in advance.

Well, lessee... Assuming local electrical codes allow it, how about
a grounded shield braid over each of those motor power leads? Or perhaps
bringing the motor's power leads through feedthrough caps in a grounded
metal enclosure?

I'm sure others will have other suggestions. Good luck.

--
Bruce Lane, Owner and Head Hardware Heavy,
Blue Feather Technologies -- http://www.bluefeathertech.com
KC7GR -- kyrrin (a/t) bluefeathertech dot-com (Reassemble to use)
"I'll get a life when someone demonstrates to me it would be superior to
what I have now..." (Taki Kogoma)