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Topic: Priority of 120 volt Sources (Read 1452 times) previous topic - next topic

Re: Priority of 120 volt Sources

Reply #25 –
Not sure about ALL  of the ATS switches on our coaches but ours doesn't have a set of NC and NO  power contacts. There are two contactors  both with NO contacts. One coil pulled in by shore power and the other by generator power.
Priority depends on how the coils are wired, as the coil of one is wired thru a NC aux contact on the other.
Justin & Cathy Byrd
1995 U280 "Old Faithful"
36' Build #4673
C8.3 Cummins
Allison MD3060R 6 speed - retarder
Powertech 10KW  4cyl Kubota

Re: Priority of 120 volt Sources

Reply #26 –
Quote from: FourTravelers –
Not sure about ALL  of the ATS switches on our coaches but ours doesn't have a set of NC and NO  power contacts. There are two contactors  both with NO contacts. One coil pulled in by shore power and the other by generator power.
Priority depends on how the coils are wired, as the coil of one is wired thru a NC aux contact on the other.

Anything to save a dollar.  With a remote possibility of both sets of contacts being closed at the same time.
1992 Foretravel Grand Villa
U225 SBID Build No. 4134
1986 Rockwood Driftwood
1968 S.I.A.T.A. Spring
1962 Studebaker Lark
1986 Honda VF700C
1983 Honda VF750C
Charlie, the Dog was broken out of jail 24 Oct 2023
N1RPN
AA1OH (H)e who must be obeyed.

Re: Priority of 120 volt Sources

Reply #27 –
You have a dilemma. . . Some transfer switches are shore priority, and some are gen priority.  Our coach is shore priority.

We cover your situation by wiring a front of bed switch to the small diameter shore transfer switch relay coil. When that coil is not powered it acts as of shore power is dead. This mod has come in handy several times.

I think your only solution is opening your live-voltage transfer switch and disconnecting a shore wire, maybe to the coil. Probably not a good time to understand how transfer switch is wired. Assume your 50 to 20 amp adapter is inside the bay door.