Malfunctioning Converter?

[jefe]

I bought my BF about 1 year ago and immediately switched out the converter as advised with the progressive dynamics unit (PD4655). Right now my RV wont charge unless the truck engine is running. It will not recognize being plugged in and does not respond to the generator running. The lights and fridge (on LP) work but the AC, Microwave and outlets do not run (as they shouldn't when there isn't access to power beyond the batteries). Is this definitely an converter problem? Any idea what might be going wrong? I took the panel off and checked that all the wires were still connected and they were. The green light is solid on for the PD converter.

[randallrae]

It sounds like you might have tripped your main AC breaker , check all your breakers.

[whemme]

Try this.

Go to my post titled Hidden Generator Circuit Breaker in the Technical Library section on this forum.

Or you can go to it by clicking on the following direct link: http://www.bornfreervclub.org/bulletin_ ... =18&t=4375

[jefe]

I did NOT realize there was a breaker on the generator. Thanks again Bill, don't know what I'd do without you.

[randallrae]

Remember it is best to unplug the coach before starting the generator .

[whemme]

randallrae,

Sorry, but I disagree with your recommendation. It is not necessary to disconnect from the AC power pedestal before starting your generator in your Born Free motorcoach. Your Born Free is equipped with a time delay AC transfer relay. This relay in its normal state connects the power coming from the AC power pedestal to the AC power bus inside your coach. When you start and run the generator, there is a 20 to 30 second delay and then this relay switches the AC output of the generator to the AC power bus inside your coach and disconnecting from the AC power pedestal.

This 20 to 30 second delay is to allow the generator time to stabilize and be ready to accept what ever AC loads are on inside the coach.

If you have technical information that recommends that before starting the generator, that the AC power cable plugged into the power pedestal should first be unplugged, please enlighten us.

[oliverpsmile]

Bill, for some reason my generator (after 15-20 seconds) got in parallel with the shore power. The Shore Power breaker in the house tripped first. May be the transfer switch makes before breaks the connections. I do not know. I did not investigate.

[jefe]

That got the generator charging the coach again, but it dies when I try to run the AC after a few minutes. Is there an electrical fix or do I need to service the generator?

[randallrae]

Bill the transfer relay in our Born Frees is to prevent the generator back feeding power into the power lines . The transfer relay does this whether the generator is in phase with incoming power or not . If the two power sources are not in phase this can create a power surge when the relay energizes , and that can cause breakers to trip .

[whemme]

Bill the transfer relay in our Born Frees is to prevent the generator back feeding power into the power lines . The transfer relay does this whether the generator is in phase with incoming power or not . If the two power sources are not in phase this can create a power surge when the relay energizes , and that can cause breakers to trip .

randallrae,

I agreed with your first sentence but not with your 2nd and 3rd sentences. The AC power input from power pedestal and the AC power input from the generator when running are totally isolated from each other by the transfer relay. They can't interfere with each other because they are isolated from each other by the mechanical contacts in the relay. Since that is true, it really does not matter whether the AC voltage from the power pedestal is in or out of phase from the AC voltage coming from the generator. Also, there is no way for the phase relationship between the two sources to stay in or out of phase anyway. The frequency of the AC voltage coming from the power pedestal will be a very accurate 60.000000 Hz whereas the frequency of the AC voltage coming from the generator can be as high as 63 Hz and as low as 57 Hz assuming the governor is set properly on the generator. Whatever the generator voltage frequency is with no load on the generator, it will drop somewhat under a load. This difference in frequency between the power pedestal and the generator means that the phase relationship is constantly changing. But as I said, it does not matter since the job of the transfer relay is to isolate the two sources from each other anyway.

[whemme]

That got the generator charging the coach again, but it dies when I try to run the AC after a few minutes. Is there an electrical fix or do I need to service the generator?

Jeff,

You don't state if your Born Free is equipped with a Onan generator or a Generac generator. If it is an Onan then I have some experience with that generator.

First question, did this problem with the generator quitting after running awhile under the load of the air conditioner just start or has it been a problem for a while?

Second question, will the generator kept running so say 1/2 hour as long as there is no load on it?

Third question, when the generator quits while under the load of the air conditioner, does is slowly die like it can't handle the load anymore or does if run at normal speed then then just suddenly quit?

First, I would say that your generator does not have an electrical issue. Depending on the answers to the above questions and assuming the generator is an Onan, I will make a wild guess that your problem is a defective fuel pump. On way to check this is right after the generator dies, pull off the rubber fuel hose going into the fuel filter. If you have no or any a small dribble of fuel falling out of the open end of the fuel hose, then you have a bad fuel pump.

Let us know what you find.

[randallrae]

http://www.davidsonsales.com/NPD_Vs_IPM.htm , https://www.cumminspower.com/www/litera ... ion-en.pdf Ours are open-transition transfer switches .

[whemme]

randallrae,

OK. I agree with you that if the air conditioner is running from power pedestal AC power and then if you were to start the generator, after the transfer relay delay as the mechanical contacts of the relay transfer power to the running air conditioner from the power pedestal to the generator that as the contacts move from one position to another, the air conditioner may be without AC power momentarily (like for maybe only 0.01 seconds). During that time, the air conditioner compressor and fan motors work like a generator themselves. If the AC voltage at the power pedestal happens to be out of phase with the AC voltage out of the generator at that instant in time, I agree with you that there will be a major bump or jump in the the AC current between the generator and the air conditioner. However, that is protected by either the 30-amp breaker on the generator and/or the 30-amp AC input breaker on the coach's power panel.

The air conditioner is the only AC load that exhibits this problem as it is the only AC appliance utilizing high current AC motors that can cause this out of phase momentary high current switch over problem.

I have attached page 6 from the 2015 Born Free Owners Manuals below. Note the very 1st paragraph titled Operating Instructions. It states the following: The AC / Heat Strip must be in the OFF position when the generator is started or when the shoreline power cord is plugged in.

I think this recommendation is to prevent the very problem you are referring to and I thank you for pointing it out.

[randallrae]

As Cummins states the contact arc can cause this problem , so the refrigerator , water heater , and converter can contribute enough of a current draw to cause arcing . I don't know if all converters use transformers , but I'm sure the older converters did ,and that causes the same inductive load problem caused by the air conditioner . I doubt leaving the power on will hurt the transfer relay , but I think it is why the breakers occasionally trip .

[whemme]

I think the only inductive load of consequence would be the air conditioner. If as the Born Free Operators Manual instructs if you shut of the air conditioner before starting the generator, that will eliminate the possible inductive feedback problem when the transfer relay switches modes.