Auto transfer switch

[Beau388]

Originally Posted by surclan1

I appreciate the offer but I feel like I need to learn this rig for myself. Cw not very helpful

Just be careful as there is a good chance that you shore line plug is hot (has voltage) while running your generator.

[surclan1]

Thank you and I appreciate your knowledge.

[blw2]

Originally Posted by Beau388

Just be careful as there is a good chance that you shore line plug is hot (has voltage) while running your generator.

I've gotta admit I never considered this possibility. It does seem plausible though that a fault like that could happen. That open ended plug is just flopping around loose in the storage bay...sometimes with a wet rag or whatever. I wonder if some sort of cap over the plug would be a good safety idea.... I guess it's an unlikely thing though

[16ACE27]

Originally Posted by blw2

I've gotta admit I never considered this possibility. It does seem plausible though that a fault like that could happen. That open ended plug is just flopping around loose in the storage bay...sometimes with a wet rag or whatever. I wonder if some sort of cap over the plug would be a good safety idea.... I guess it's an unlikely thing though

No, not in his case. If his ATS is cross-connecting the generator to SP causing both the generator and the SP breakers to trip when running the generator while plugged into SP, I would just about guarantee the SP plug is hot while running the generator. The real question is what is happening to the generator by backfeeding it from SP?

[surclan1]

Sounding like wiring may be incorrect. Does anybody have wiring schematic?

[16ACE27]

Originally Posted by surclan1

Sounding like wiring may be incorrect. Does anybody have wiring schematic?

30 or 50 amp?

[surclan1]

50 amp

[16ACE27]

Once you remove the top (cover) of your switch you should see a specific schematic for it on the underside.

This is a general schematic. You don't need to worry about the wiring/connections for the time delays as they are internal and not your problem. You need to look at how the main power connectors (L1, L2, Neutral) from SP, the Generator, and the load side are connected:

[16ACE27]

Did you make any progress today?

[surclan1]

Wiring looks good. If I had ac on when switching to generator do you think it would cause circuits to trip?

[Chateau29Z]

The self excitation in the generator winding will be opposing the shore power. My genset (Onan) won't crank over with shore power on.

[TurnerFam]

in today' RVs, with onboard generators, there's no issues with starting/running the generator, whether on shore power or not, as the ATS will transfer the power from the generator automatically, making it the default power source if both are available. The two power sources are not connected.

in some less recent models, the owner would need to physically move the shore power cord from the power pedestal to the interior 50amp plug in order to receive the generator's power, though this in itself has nothing to do with whether you could crank/run the generator while plugged into shore power. The two power sources are not connected.

most issues with Generators revolve around low fuel, low oil/pressure, and the failure to realize that they must have time to 'prime' the glow plus and/or the fuel before cranking. In today's model motorhomes, even if you already have some heavy loads 'ON' when the generator cranks, the system is designed to 'wait' until the generator is fully 'running' before the loads are allowed to be powered, which is why you may have to wait 20 to 30 seconds before you hear the ATS 'clunk' over to the generator power. Even Air Conditioners are designed to only start their FANS at first, and then 10 or 15 seconds later the compressor.

[16ACE27]

Originally Posted by Chateau29Z

The self excitation in the generator winding will be opposing the shore power. My genset (Onan) won't crank over with shore power on.

Then you have a problem. The output of the generator isn't connected to the AC Buss at all until after it is running and the time delay times out. Then the ATS disconnect SP before it connects the generator to the AC Buss.

[16ACE27]

Originally Posted by surclan1

Wiring looks good. If I had ac on when switching to generator do you think it would cause circuits to trip?

"AC" as in 120 VAC or Air Conditioning. The answer should be no in either case although switching the ATS with a heavy load such as Air Conditioning is not recommended as it causes excessive arcing and wear on the contacts and stresses the load with the power fluctuation.

[Martinez]

Why would you want to start the generator if it's plugged in? I'm new to this

[Pete'sMH]

Originally Posted by TurnerFam

in today' RVs, with onboard generators, there's no issues with starting/running the generator, whether on shore power or not, as the ATS will transfer the power from the generator automatically, making it the default power source if both are available. The two power sources are not connected.

in some less recent models, the owner would need to physically move the shore power cord from the power pedestal to the interior 50amp plug in order to receive the generator's power, though this in itself has nothing to do with whether you could crank/run the generator while plugged into shore power. The two power sources are not connected.

most issues with Generators revolve around low fuel, low oil/pressure, and the failure to realize that they must have time to 'prime' the glow plus and/or the fuel before cranking. In today's model motorhomes, even if you already have some heavy loads 'ON' when the generator cranks, the system is designed to 'wait' until the generator is fully 'running' before the loads are allowed to be powered, which is why you may have to wait 20 to 30 seconds before you hear the ATS 'clunk' over to the generator power. Even Air Conditioners are designed to only start their FANS at first, and then 10 or 15 seconds later the compressor.

Actually many current RVs don’t even have an ATS. My 2017 Winnebago doesn’t and I’m glad. It works as you indicate you just plug the cord into either the campground utility or the generator inlet in the electrical compartment. When I disconnect from the campground I plug into the onboard inlet and there you go. It’s one less device to worry about (or pay for....). 2016 Fleetwood was this way as well.