On 10/14/2013 7:13 PM, dpb wrote:
....

Your choices as I see it are--

a) replace the GFCI w/ a different/newer one and see if goes away for at
least a while,

b) replace the motor w/ one that doesn't have the leakage current. It's
highly unlikely you'll be able to change its characteristics any
although despite no heavy dust buildup you might try blowing it out
thoroughly w/ compressed air to see if internal dust could be
contributing to the problem, or

c) do away w/ the GFCIs

Oh, there's no fluorescent lighting on the circuit is there?

And, while it's less likely given the two circuits both behave the same
now, look for and check all circuit connections to eliminate any high
impedance ones (relatively) that could contribute to the small imbalance.

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