smkettner wrote:
I think the delay modules also convert power to 120v DC to operate the control coil.
Maybe operating the coil on DC stops the frequency shift that PI picks up.
the unit’s DC coil prevents AC “chatter” noise
hmmm, yes, that's what KJINT was suggesting a few posts up. Thanks for the link.
The WFCO doc says "the unit’s DC coil prevents AC “chatter” noise and drop-out in low-voltage conditions", meaning low AC voltage. But that's covered by the EMS already so shouldn't be happening. The EMS display doesn't report a low VAC either, but does briefly show a high HZ.
My issue appears to be more with presence/absence of loads when the new relay is activated. With no loads when the new relay closes, the EMS does not detect any abnormally high frequency and is happy. When there are loads, it aborts with the High Freq error message. That's why I suspect contact arcing is problem.
