Onan 6300 LPG generter putting out 154.6V

[chollenback]

I went ahead and fired up generator and took readings at all outlets and they all read 154.6V when generator is on. This is way to high. I see that Voltage regulator was replaced in 2014 according to paperwork. I guess regulator is fried but I want to ensure it is not something else and that I prevent this from occurring the next time.

Model number is 6.3NHEFA63753J

120 V

52Amps

6.2KW 60Hz/ 1Ph

 

What do I need to do to get this back within specs. Now I know why I was smelling "burning" when it was running.

 

Thanks

[wolfe10]

Yes, that is WAY too high.

What is your HZ-- wonder if that is too high as well.

[manholt]

I would call Onan (Cummins) ASAP!

[kaypsmith]

Check all connections between generator and transfer switch, a loose or open neutral will cause high readings, as well as other things. I would check the ATS very carefully for loose connections and faulty relays. Definitely believe that the frequency (HZ) needs checking. Were it mine, I would disconnect from the ATS to start my checking and corrections, when loose from the ATS, be sure that you check voltage then, if in normal range, change the ATS. Yes Carl,  I would call in a qualified technician, especially if the voltage still shows high while disconnected from the ATS.

[wolfe10]

Not sure how an ATS could cause high voltage ??

[kaypsmith]

Sorry, I re read the post, and checked the model # of the generator, it is a 120 volt generator, so my comments are not valid. A loose or missing ground on a 240 volt system could cause this, but not on a 120 only. Overspeed of the engine or arching commentator could be the cause of over voltage. Most 50 amp coaches uses 240 volt generators is basis for original comment. I'm not sure what speed motor that generator uses, but many are 2500 rpm with an larger pulley on the motor and a smaller one on the generator to spin the generator at 3600, it would not take to many over rpm to drastically change the frequency which in turn raises the voltage. I would still disconnect generator from the ATS for testing the generator, too many volts will fry other components in the system.

[desertdeals69]

If the frequency is between 59 and 61 the rpm should be 1800.

[jerrycarp]

I just went out and looked at my gen (same as op) this unit has two circuits 30 amps each feeding into the ats feeding each leg of ats. , so I believe you could have loose neutral.

While my ats is open I think I will check lugs.

Jerry

[wolfe10]

Jerry,

Would appreciate your checking to make sure you do have 240 VAC between the hots.  Many generators with two hots do not.

[jerrycarp]

No it is not 240v , correct me if I am wrong but your 240v 50a service is split back to 2 120v lines at the Ats to feed service panel.

Just like the shore power the gen has two hot legs with common neutral. After checking lugs and because of your request good time to exercise gen with both ac running each leg reads 126v. If op feels they can safely check, it would not hurt to check for balance it is simple and quick

Jerry

 

[wolfe10]

Jerry,

Yes, some generators are wired with the two hots "opposite each other" (will read 240 VAC between them).

But, others are wired with the two hots "on the same side" (will read 0 VAC between them). If this is how it is wired, an open neutral will not result in high voltage.

Give Onan a call with your model and serial number, they can tell you which way yours is wired.

 

Onan 1-877-938-6762

[kaypsmith]

Sorry to have caused too much controversy, I have been unable to locate any manuals on this unit, but have now viewed pictures enough to determine that it is a 120 volt only unit. Also it is a direct drive motor to generator, which means no drive belt (good) and that it will have to be 1800, or 3600 rpm, this vintage Onan would be 1800 4 windings. Definitely 0 volts between each side.

[chollenback]

will call Onan. I do not want to fry anything.

I will post back what they tell me.

Thanks

[dickandlois]

On 7/18/2018 at 7:35 PM, chollenback said:

I went ahead and fired up generator and took readings at all outlets and they all read 154.6V when generator is on. This is way to high. I see that Voltage regulator was replaced in 2014 according to paperwork. I guess regulator is fried but I want to ensure it is not something else and that I prevent this from occurring the next time.

Model number is 6.3NHEFA63753J

120 V

52Amps

6.2KW 60Hz/ 1Ph

 

What do I need to do to get this back within specs. Now I know why I was smelling "burning" when it was running.

 

Thanks

chollenback,  In your original post you posted the  Model as 63.NHEFA  plus a series of numbers,This series falls into the Onan Emerald  series. There is an issue with the fuel used with the model you posted using the charts I have.

         The 6.3NHEFA is listed as a gas powered unit.

          The 6.3 NHEL( ) series is listed as an LP fueled unit.  There are 4 different versions of them listed with different regulator boards offered -so if you contact Onan, make sure you get the proper information required. 

 Is the series label difficult to read? and if so, can you read the serial number clearly - that might be a better route to take or at least an option so one gets the proper information and parts.

Rich.   

[chollenback]

I called Onan and they were no help. I did massive research on these things but I am still a little confused as things contradict what I should do. 

Volts are still high and Hz is at 61.8Hz. I read that Hz can be between 60-63Hz. Not sure if this is right. If it is 60Hz I think it should be the max.

Voltage Regulator appears to be working because it keep constant voltage (I assume it is working - if it was not I think I would get wacky voltage jumping all around).

Any ideas?

 

[dickandlois]

44 minutes ago, chollenback said:

I called Onan and they were no help. I did massive research on these things but I am still a little confused as things contradict what I should do. 

Volts are still high and Hz is at 61.8Hz. I read that Hz can be between 60-63Hz. Not sure if this is right. If it is 60Hz I think it should be the max.

Voltage Regulator appears to be working because it keep constant voltage (I assume it is working - if it was not I think I would get wacky voltage jumping all around).

Any ideas?

 

OK , Try this information and see if they can be of any help. Remember the devil is in the details !!!!!

Rich.

onan-rv-troubleshooting-guide.pdf

 

[manholt]

Your Hz is in range, but your #2 pin is loss or regulator needs to be replaced.  Check #2 pin first.

[kaypsmith]

Do you have a 1500 watt electric element heater? If you do, place it on the highest setting with nothing else on in the coach, take a voltage reading this way, if it drops below 128, you will probably be ok. What type meter are you using? If so, have you checked from the S&B wiring to verify that it has not gone wacky somehow. I have seen false readings on a digital meter with a low battery in the meter.

[manholt]

I got the old fashion, red & black prob!  Does a digital need re-calibration?

[dickandlois]

This is what the voltage regular looks like. http://www.flightsystems.com/p-ONAN-305.html  

This is an aftermarket unit that was made to transfer heat better, There is also a model(the red link) on the information sheet that is a direct mount with a metal case. 

Link -----http://www.flightsystems.com/p-ONAN-305-0826.html

You need to match the regulator boards up. The other board that fails is the control board , but your unit appears to start - you have not mentioned any starting issue.

These control boards are both pron to heat damage, often caused by poor cooling air movement and that problem is best addressed by cleaning the generator(with all the old filters still in place, 35 to 40 lbs. of air pressure) Removing the air filter, check for any damage to the blower, clean with air if necessary and replace the old air filter.

Hope this helps.

How often and when where the filters and other service intervals performed?  If the pictures do not match what you have, please take a picture and see if you can get a part number(s) 

Rich.

[chollenback]

Rich/Manholt,

The name plate on outside says Model: 6.3NHEFA63753J Serial Number K943255498, 120V, 52A, LP fuel, 6.3 KW, 1800RPM, 12V. it is propane (I wonder if they switch the covers). I tested the regulator pins per the book and they all were closed except when testing 10-5 pin. This is what the book said that it would be open and read 0 (which it did). I lowered the governor speed to get it 132 Volts and 56Hz but when I turn on A/C and refer it drops to 122 volts and 52HZ. if I put on other A/C it pops automatic transfer switch (I think it does this because of the low voltage).    

Kaypsmith: The regulator was changed in 2014 and he replaced with a B305???? ( I am not home to get paperwork out to look at P/N). I did see that this Voltage regulator can be rebuilt and was one of the selling points (I guess). I will take pic of VR when I get home. I do recall that it looks like what Rich posted in his link but I have a larger capacitor looking thing on mine (looks like a size of a "D" battery).

I see that he kept great records of the upkeep and it has been serviced routinely.

I did find out that I can turn the generator on and of inside the RV at the panel but I can only shut it of at the generator and not start it. This appears to be a control board issue. However, everything I read says that this has no bearing on the voltage (it just regulates the oil pressure, fuel, etc.,)

Does this help or does it muddy the water :0

 

[dickandlois]

chollenback, Thanks for your reply and information. Every piece of information helps / it tends to help pin down items. Does not always speed things up! 

The only item missed was the service records and it sounds like you intend to send that once you get back home. 

One would hope that the Regulator would last longer then 4 years !!!!!!   The fact that heat is a known issue for failure and there are 2 versions of it offered ?   

           You did mention that the picture info I sent looks like the one currently installed. So I'm thinking the current one (because of the part number) is an OEM replacement. That could be cleared up once you are home.

Your RPM to frequency and voltage at this point tend to lead me to the Voltage Regulator. NOT having the wiring diagram to see how the regulator module is interfaced with the armature winding leaves me with a gape. There are given resistance readings that should be checked along with all the internal and external connections related to the alternator.

The test you conducted on Control Board, sure would  tend to mean it is in good condition.  The start / stop issues could be just a connection issue at the module and or inside the coach - then again those wires running between the 2 could be an issue . The switch on the Module should be mirror at the remote switch.

Rich.

No Number to cover issue. (the generator is ether Gas or LP, not a hi bread) Looks like a labeling conundrum. Maybe it is me. LOL 

[chollenback]

Rich,

I did a quick search and this is the exact same one I have.

http://www.randkproducts.com/used-onan-63-nhefa63753j-lp-generator-p-698.html

You can see it is same model as mine but does not appear on any Onan manual as LP.

I will post pics when I get home.

Thanks

 

 

[chollenback]

Maintenacne done about every 250 hours. PN for voltage regulator is 0305-0809-01

[chollenback]

OK guys here are the readings of the VR 305-0809-01-HC-0003441F22

Pins    OHMS

5-9      596

7-9      865

10-9   619

11-9   695

12-9   708

10-5   1 (this is correct per the book)

5-11    697

5-12    692

5-3       880

Are these readings OK? It looks like this is OK, but I am no expert.

Thoughts?