Onan generator shorted (110 side)

[vacuumbed]

Hello everyone.

My 1978 Pace Arrow developed an issue. When the shore cord is pugged in to power it will trip the residential house breaker immediately.

I traced it to the generator, which is an Onan 6.5 gas unit. The Hot and the Ground has full continuity! This can't be right. Has anyone heard of this issue?

I'm thinking the voltage regulator is blown or there is a problem in the generator itself.

[TEXAS]

Since you have voltage. No damage was done. If the engine is going up and down. That would cause your voltage swing most of the time. Do as Jim says and you will be ok.

[Generator_Jim]

134 vac is a little high. If you have a frequency (Hertz) meter, connect it across the 120 volts and adjust the governor speed spring on top of the cooling fan for 62 at no load and 58 at full load. Your voltage should be within tolerances at that point.

JimL

Scott and Sherrie -- where have you been, I missed you.

[PaulJ2]

The older non regulated generators are voltage controled by the engine speed only. So any hunting or deviation of speed affects voltage/frequency. They depend on some load to help keep them stablized. 134 volts with no or light load will probably be 120 or so with a load which is fine.

[ScottnSherrie]

vacuumbed wrote:
I ran it and it's putting out 125 to 134 volts with no load.

The range is ok but the fluctuation is huge. I would think it should hold voltage with less than one volt fluctuation.

[vacuumbed]

I ran it and it's putting out 125 to 134 volts with no load.

[vacuumbed]

This is the best news I've heard all day! I am going to fire it up and check the voltage.

[PaulJ2]

ScottnSherrie wrote:

vacuumbed wrote:
With the coach disconnected, the HOT side of the generator has full continuity to both Neutral and Ground. This can't be right.

Well, I think that might be ok. I think hot and neutral/ground would be connected through the coils of the generator. I'd run out and check on my older Onan but am over 900 miles away at the moment.

Agree: I think you will find they are connected through the generator windings as above.

[ScottnSherrie]

vacuumbed wrote:
With the coach disconnected, the HOT side of the generator has full continuity to both Neutral and Ground. This can't be right.

Well, I think that might be ok. I think hot and neutral/ground would be connected through the coils of the generator. I'd run out and check on my older Onan but am over 900 miles away at the moment.

[vacuumbed]

TEXAS wrote:
The Onan units of that time. Did not have regulators. Most likely you have back fed the generator. Which will burn out the stator and can also damage the rotor.

Need to know what genset you have.

This is the type of information I'm looking for. I'm hoping my generator can be repaired.

With the coach disconnected, the HOT side of the generator has full continuity to both Neutral and Ground. This can't be right.

[vacuumbed]

wolfe10 wrote:
Again, let's address the root cause of the problem-- how did shore power get to your generator.

Do you have an ATS?
Do you manually switch from shore to generator by changing plugs?

In either case, you need to find out how shore power reached the generator.

As I mentioned earlier, I rewired the ATS which caused shore power to reach the generator.

I am going to remove the ATS so the shore cord has to be plugged in to the generator.

As the OP what I need to focus on here is how to repair my broken generator.

[wolfe10]

Again, let's address the root cause of the problem-- how did shore power get to your generator.

Do you have an ATS?
Do you manually switch from shore to generator by changing plugs?

In either case, you need to find out how shore power reached the generator.

[Kpackpackkelley]

Bfa a-c bf a-b nh j-p bga a-c service manual 900-0337
Maybe this will help.

[vacuumbed]

I just want to pop in and say that I appreciate all of your help on this issue.

[vacuumbed]

Here is the model #

6.5 NH-3CR/16004K

[TEXAS]

The Onan units of that time. Did not have regulators. Most likely you have back fed the generator. Which will burn out the stator and can also damage the rotor.

Need to know what genset you have.