Transfer Switch

[Lastbeer]

Howdy all,
Purchased a used fifth wheel with a Onan 5500 generator. It impressively ran all three A/c units and coach. The coach was plugged into shore power, and I cranked up the generator.

After that, the coach was not getting electricity from shore power. I tracked the problem to the transfer switch.

Question: My assumption is that the transfer switch cannot handle two electrical inputs. Can anyone offer other suggestions?

Thanks,
James

[Mopar_Earl]

Yes it can. When the generator starts there is a little bit of a time delay and the switch will switch the trailer from shore power to generator power. Shut the genset down and it goes back to shore power. If yours doesn't work that way, there is an issue. Be sure to wait long enough for the time delay. It's allows the genset to stabilize before it's loaded.


Earl

[Lastbeer]

After both were providing power, the shore power relay started to not engage fully.

I am assuming that was the cause. I am about to buy a new transfer switch $150.

Thank you for your input.

[Mopar_Earl]

Check your wire lugs first before you order. Mine were very loose. Unplug your shore and genset off when you check it.


Earl

[Scottenj]

Originally Posted by Lastbeer

After both were providing power, the shore power relay started to not engage fully.

I am assuming that was the cause. I am about to buy a new transfer switch $150.

Thank you for your input.

I assume you are nowhere near Massachusetts because I am selling a 50 amp transfer switch with built in surge protection.

[Camper_bob]

The transfer switch is set up to "prioritize" generator power. If you have generator power as well as shore power incoming to the ATS, you will be using the generator's power. Cut off the generator, and the ATS will switch over to shore power. Power the generator back up, and it will switch back to generator.

You need to test each source independently if you want to trouble-shoot the ATS. And as you're switching back and forth between power sources, it's a good idea to shut down any high draw appliances like the AC units, the water heater (or any electric heater), microwave, etc.

But what OP is describing is normal and expected behavior.

ETA: Just read your follow-up post again. Sounds like shore power doesn't engage correctly after generator input is removed? If that's the case, you could open up the ATS and clean the contacts. Or as was stated before, make sure all the wires are tight. Loose wires on the AC side of power cause all kinds of nasty problems.

[Lastbeer]

The shore power relay is not fully engaging. I can push (wooden stick) on the relay and fully engage.

The relay is closed (physically designed), so I think I will take your advice and disconnect all, dismount box, and try to clean. Then reinstall and test.

Thank you for your ideas.

[Lastbeer]

Texas. How much are you selling it for?

Originally Posted by Scottenj

I assume you are nowhere near Massachusetts because I am selling a 50 amp transfer switch with built in surge protection.

[Mopar_Earl]

Originally Posted by Lastbeer

The shore power relay is not fully engaging. I can push (wooden stick) on the relay and fully engage.

The relay is closed (physically designed), so I think I will take your advice and disconnect all, dismount box, and try to clean. Then reinstall and test.

Thank you for your ideas.

Switch is hanging up or the pull in coil is weak or bad connections to the coil.


Earl

[Camper_bob]

It very well could be no good. They're not notoriously reliable in my experience and from what I understand from others.

[Scottenj]

Originally Posted by Lastbeer

Texas. How much are you selling it for?

$100 but I am trying to sell it locally where someone picks it up, I wasn't thinking in terms of having to ship it somewhere.