Transfer switch or generator?

[Old Dude 66]

Coming back from our Colorado summer trips the last two years, we were running the generator and ACs to keep cool. Both times, about half way back to Texas, we lost power coming from the generator. The gen was still running but the coach wasn't receiving the power. I checked the breakers to no avail. The monitor board is always blank when it does this.

Last year, we took it in and were told the breakers were weak and were replaced. This year it did it all again. I started it up to take it in for service after sitting for about a week, and, lo and behold, the gen was working fine. It ran fine to the repair place (about 30 minutes away). Service folks at Coach Specialist in Mansfield say they don't have a clue since they can't find the problem as long as it is working.

I called Cummins/Onan and they said it can't be the gen and that it shouldn't even be running if it isn't putting out power. They think it is probably the transfer switch.

We have a 2011 Winnebago Adventurer and I have hard wired a Surge Guard. Could it be the Surge Guard causing problems or maybe the transfer switch?

I have read all of the transfer switch posts I can find.

[Dr4Film]

The correct way to confirm whether it's the transfer switch or not is to wait until it happens again, then with the generator still running, remove the cover from the transfer switch and using your DVOM measure the output side of the transfer switch to see if power has transferred through the relay's. While there you could also verify power on the input side of the generator relay.

If you have power on the input side of the generator relay but none on the output side you have just found your problem.

Dr4Film ----- Richard

[Gary RVRoamer]

You say you checked the breakers, but was that the breaker(s) on the generator or the ones in the coach. The generator will continue to run if its output circuit breaker trips.
It could be that the transfer switch gets flaky when hot. I had that problem with mine, but it is mounted next to the engine (its a DP) and the monitor circuit board got a false failure when it got hot enough. In a typical transfer switch, it could just be a solenoid failure or a relay that lets loose.

[Old Dude 66]

I checked the breakers on the generator. The problem with waiting until it happens again will be when we are traveling on a hot day after about 5 hours on the road. Not a good time to stop somewhere and start circuit testing. I didn't think to check the coach breakers. The shop now has it running in hopes of getting it to do its trick so they can check it out. Betcha $100 it won't do it today. Not near hot enough and it only does it after a long time running in the heat. We have extended warranty but I am about ready to have them start throwing parts at it with my paying the cost.

[ImagineIF]

If it's not hot enough to keep the ACs running, turn on some other loads. Do you have a dryer? Plug in a portable heater and turn it on high with the AC going. You just need to load the generator.

As stated, when it happens again, don't turn off the generator until you've found the problem. Some transfer switches look at the voltage and possible frequency on the generator side of the transfer switch. If either is out of range, they turn off power to the coach. If this happens and the out-of-range readings come back in range then power will be restored after the transfer switch's timer expires. The timer is typically 90 - 120 seconds.

[wa8yxm]

If you are good with electrical, or know someone who is.

have them install a pair of single outlets, with fuses to protect, on the generator output (I'd connect them in at the transfer box)

When you loose power simply popping a night light into those outlets will tell you...LIGHT LIGHT = Switch DARK DARK = Generator, Light Dark=likely generator (or dark-light)

I like test lights, way easier than volt meters.. Though a Kill-a-watt in volts mode may be of use too since 45 volts may light the light, but not transfer the switch.

[teddyu]

On my unit, between the generator output and the transfer switch is a junction box where the leads from the generator (factory provided) are connected to wiring supplied by the MH manufacturer that goes on to the transfer switch. Mine is under a cabinet base. Found by removing the bottom drawer. Just a note, if power is not sensed at the transfer switch from the generator, the transfer switch will return to the SP position. My junction box uses standard twisted wire nuts to connect the two sets of leads. When I found the junction box, the wire nuts were tight, but I over-taped each nut to ensure the wire nuts would not vibrate loose. Wire nuts are good for home use (no vibration) but come-on, in a MH please! JM2¢...

[gatorcq]

My suggestion is to locate the ATS, remove the cover and check the connections. There were some ATS 4 to 8 years ago that were produce and failed due to loose connections.