Gen keeps running, all power shuts off, thumping noise behind breaker box

[Txtnt]

We have an 2013 XLR thunderbolt with cummins 5500 generator. Generator starts and runs great. We start generator, wait a few minutes till we hear the thump and have power then turn on each A/C one at a time. All power comes on including both A/C's, but after running awhile all power shuts off. (Bare in mind generator keeps running and none of the breakers are tripped.) After all the power shuts off you can hear a continuous thumping noise behind the breaker box. The only way to get power to come back on is to shut down generator, fire it back up & then turn everything back on. Then it starts all over again, generator runs and we have power for awhile, then power shuts off while generator is still running, hear thumping noise and no breakers are tripped. Battery is fully charged, we thought unit was over heating when this started so oil & filter recently changed, but after this problem had already started. RV is parked in front of our house and does not have shore power plugged in. Headed to Sturgis in 3 days and dry camping...need help! Thanks!

[stevejd235]

Do you have a surge protector that is throwing out errors? I know my Progressive surge protector has killed my power twice because of a low voltage drop or because my Honda generator was not netural grounded.

Just something to look at.

[elind]

My two Honda 2000s together will put out 4000 watts peak for the first 1/2 hour and then it should shut down if it stays over 3200 watts after that point. The Honda manual talks about this. Does the Cummins genny have the same feature?

[DennisTD]

The "thump" you hear is likely the transfer switch. It sounds like that is dropping out.

[Still Kickin]

Originally Posted by DennisTD

The "thump" you hear is likely the transfer switch. It sounds like that is dropping out.

X2. I would try and trace the wires from the gen to the switch and check for any loose connections. But like the other poster said, could be a bad transfer switch. How does it respond if you just let it switch and not load it with the A/C draws, putting less draw like the micro. Sorry but maybe others can chime in with more insight.

[Jeff Auton]

Mine did the same thing yesterday. I have a 2015 401 amp. I had a 2014 300x14 and never had any problems with it. I turned the second air conditioner off yesterday and had no more problems. My guess is trying to run too much at one time.

[Mountndream]

can you run 2 A/C units on the generator? is anything else being used? I know on my generators, if the overload is tripped, I have to shut down and restart

[Txtnt]

Thanks everyone for comments. We checked amps at breaker, only have juice to one breaker so this is causing problem. Now in process of trying to locate access to check connections, which is proving not so easy....

[Txtnt]

Ok, had a duh moment, after reading we were checking the shore line side amp and that's why no power. So checked all connections, everything is tight. We have always been able to run both a/C's on gen power even at 100+ temp outside. Maybe transfer switch is bad and the thumping noise is it try to switch to shore power?

[DennisTD]

The transfer switch will be on shore power "normally". When it senses generator power it will switch to that after a short time delay. That is the thump sound. So if you are not plugged into shore power and you start the genny you will get 120V after the genny is on and the transfer switch time delay. If you are plugged in to shore power and you start the gen it will transfer to gen power, but if for some reason the gen drops off, either by the gen shutting down or a problem with the switch, it will switch back to shore power.

So...continuous thumping sound would suggest either the generator is not generating electrical power (but the engine is still running), the logic/time delay circuitry in the transfer switch is failing, or you have a loose power connection between the gen and the transfer switch.

Good luck. I'm counting down to Sturgis as well.

[dbryan79]

Originally Posted by Txtnt

We have an 2013 XLR thunderbolt with cummins 5500 generator. Generator starts and runs great. We start generator, wait a few minutes till we hear the thump and have power then turn on each A/C one at a time. All power comes on including both A/C's, but after running awhile all power shuts off. (Bare in mind generator keeps running and none of the breakers are tripped.) After all the power shuts off you can hear a continuous thumping noise behind the breaker box. The only way to get power to come back on is to shut down generator, fire it back up & then turn everything back on. Then it starts all over again, generator runs and we have power for awhile, then power shuts off while generator is still running, hear thumping noise and no breakers are tripped. Battery is fully charged, we thought unit was over heating when this started so oil & filter recently changed, but after this problem had already started. RV is parked in front of our house and does not have shore power plugged in. Headed to Sturgis in 3 days and dry camping...need help! Thanks!

It's just the squirrels tripping and falling down