Tranfers switch

hohenwald48 wrote:
I think the progressive low voltage drop out is set to 104 volts. If that's a cheapo 16 gauge extension cord. You will have about 13-15 percent voltage drop so you would need at least 120 volts coming in to the cord to keep the voltage at the distant end above the Progressive drop out voltage level.

I suspect your problem has no relationship to the transfer switch but power disconnect is occurring due to the Progressive detecting a low voltage condition. The Progressive contactor is the thunk you're hearing and not the transfer switch.

I think you probably need a shorter and/or fatter cord.

That makes better sense, if the OP should have one of those low voltage sensors.
I've learned some, since posting, cuz I had some problems of my own, upon arriving at our location on Thursday afternoon.
Story short, I was missing the neutral return, with shore power and I think because the twist loc shore cord wasn't seating and tightened properly. Took care of some other things along the way to this probable discovery, including some wiring heat damage inside the transfer switch, due to loose connections. What I found out with it's operation, is that shore power goes straight through the normally closed contacts, so not much to normally prevent it from low voltage there. The genset uses the NO contacts and as a result takes priority over the power feed, so when it starts, it first delays, utilizing a PC board inside and then the contacts close for energizing the circuit box, regardless of power from the shore or not. It's possible that the genset wouldn't transfer with low voltage, I guess.
Anyway and unless you have other sophisticated equipment inline, there's not much to prevent low voltage from shore power and I've seen plenty of it, in our travels.