Generator runs but no power output

[Brave Dave]

I have a 2015 Winnebago Brave 27B. It has an Cummins/Onan, 4000 W gas generator. The generator runs fine and indicates 74 hours of use. The circuit breaker on the generator itself is in the on position, the coach power cord is plugged into the generator outlet, however, there is no amperage or power being delivered by the generator.

A friend of mine who is an electrician helped me look at the system. When the generator is running there is 110 V on the generator outlet box, but no amperage.

All of the circuits and circuit breakers in the coach are on and no blown fuses. Measuring at the generator outlet box, takes all of the rest of the coach out of the equation.

The fact that I am able to detect 110 V at the generator outlet box makes me think that the generator circuit breaker is working.

Any ideas of where I can start to figure out why this is not putting out power even though it starts and runs well?

[Old-Biscuit]

Gen Outlet goes to transfer switch

No AC to RV....gen side of transfer switch not engaging

[MarvinG]

Probably totally unrelated BUT, my generator or transfer switch sometimes fails to output voltage unless I have some kind of load connected. It never fails if I switch my AC fans (only) on before I start the generator.

I’ve never worried enough to track back and diagnose that because it never fails when I do start it with a slight load waiting for voltage.

[twinboat]

Originally Posted by Old-Biscuit

Gen Outlet goes to transfer switch

No AC to RV....gen side of transfer switch not engaging

Generator outlet means no transfer switch.

[twinboat]

Open the generator outlet box and check the wire connections.

[Persistent]

Originally Posted by Brave Dave

I have a 2015 Winnebago Brave 27B. It has an Cummins/Onan, 4000 W gas generator. The generator runs fine and indicates 74 hours of use. The circuit breaker on the generator itself is in the on position, the coach power cord is plugged into the generator outlet, however, there is no amperage or power being delivered by the generator.

A friend of mine who is an electrician helped me look at the system. When the generator is running there is 110 V on the generator outlet box, but no amperage.

All of the circuits and circuit breakers in the coach are on and no blown fuses. Measuring at the generator outlet box, takes all of the rest of the coach out of the equation.

The fact that I am able to detect 110 V at the generator outlet box makes me think that the generator circuit breaker is working.

Any ideas of where I can start to figure out why this is not putting out power even though it starts and runs well?

Please post model number of generator for better advice. Usually generators of that size are connected to a transfer switch. Transfer switch may be defective or have a blown fuse.

Plugging the shore power cord into a generator outlet typically means there is no transfer switch. In that case the outlet may be defective. Are all pins making good connection to the plug. Can you measure 120 volts in the socket?

Some RV's have a large, maybe 30 amp socket, for external accessories. It may be powered from the RV main circuit breaker panel. It will have no power if the transfer switch is not connecting. Can you post pictures?

120 volts at the generator outlet means generator is working.
No current means there is an open circuit down stream.

Possible plug not connecting in the socket.
Possible socket does not have 120 volts out.

[Old-Biscuit]

Originally Posted by twinboat

Generator outlet means no transfer switch.

YEP..........manually has to plug in shore cord into gen outlet




As you suggested.......need to open Gen Receptacle and check wiring connections

[wolfe10]

The on-generator breaker can appear in the on position but be tripped.


Turn it OFF and back ON.


Then pull out your voltmeter and check the outlet you plug your shore power cord into.


Let us know what you find.

[tap4154]

You probably have an open circuit somewhere. Maybe a wire is loose in your 30 amp outlet box, or it's a bad receptacle. I would start there, then check wire connections at your internal outlets and breaker panel. Have you replaced any 110 outlets recently? As Wolfe10 said, turn the generator breaker on and off. May not have fully engaged, or may be failing. Mine has the same setup, with no transfer switch.

[bigchick]

i've been thinking bout this also. you have voltage but say no amperage (current flow). how are you determining no current flow? you need a load to have current flowing. if you are just plugging an amp meter into the receptacle there is no load and no current flow. are you using the current flow show on a surge protector / ems display? they will show no current flow if there is no load downstream.

do the 120 volt devices work if you plug into shore power?

do you have a 30 amp to 15 amp adapter? if you do what happens if you plug it into the generator receptacle and put a load like a light or radio on the 15 amp output side?

i'm thinking you have an open circuit after the generator receptacle. this could be the shore power cord, where the shore power plugs into the rv, or at the main breakers in you electrical panel.

do you have an EMS installed in the incoming shore power path? if so, it is showing an error and interrupting incoming power.

time to get the meter out and start tracking the power path. just measure the voltage and each and every connection point. don't worry about the amperage. the open circuit is causing the lack of current flow (no load, no current flow). find where the voltage disappears and correct the connection.

i'm kind of surprised that your electrical friend couldn't figure this out.

[Brave Dave]

I am checking voltage and power right at the receptacle box from the generator. I would think that the rest of the recreational vehicle would be out of the equation as the only thing I am checking is the generator and the plug that the vehicle cable plugs into since I have no transfer switch.

I am checking the voltage with a fluke 77 V meter and I am checking the current with a clamp on amp meter. If I plug the coach power cord into the generator receptacle, no 110 outlets or appliances like the microwave have power.

I will try the breaker switch again tomorrow morning, however, I think I have tripped it and reset it two or three times.

Thank you for all the suggestions, let me know if the information I have provided stirs any additional thought.

[Brave Dave]

Originally Posted by MarvinG

Probably totally unrelated BUT, my generator or transfer switch sometimes fails to output voltage unless I have some kind of load connected. It never fails if I switch my AC fans (only) on before I start the generator.

I’ve never worried enough to track back and diagnose that because it never fails when I do start it with a slight load waiting for voltage.

I'll apply a load and try again. Thanks for the idea! Ill update tomorrow.

[Brave Dave]

So I did not follow my engineering training of changing one variable at a time.....but the generator is now producing power.

A point of clarification of my system. I do not have a transfer switch, but have a manual transfer system. The generator has a 30A outlet in a basement compartment. The coach has a 25' 30A power cord. The cord can either be plugged into shore power or the generator outlet.

I tried all/most of the suggestions all at once. I tripped the generator breaker 3 or four times (generator not running) and then left it in the latched closed position. I opened up the generator outlet box and tightened the ground wire nut, and the 3 screws on the back of the generator 30A receptacle (black wire allowed 1/2 turn, others were very tight). I plugged the coach 30A cable into the generator 30A receptacle and turned on my Victron inverter to charge only. I turned on the heater fan only and started the generator. I was bummed when nothing happened. Seemed like 10 seconds later......the fan started and Microwave clock turned on. I let it run for about 15 minutes and shut it off. I restarted the generator 2 additional times with the fan on and it worked each time....after about 10 seconds.

Is the 10 second delay normal?

Thanks to all for the tips. Fingers crossed.

[MarvinG]

Yes it is for mine.