Onan 6300 LPG generter putting out 154.6V

[dickandlois]

On 7/29/2018 at 1:13 PM, chollenback said:

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?

There is no reference to resistance information you offered. 

This is a PDF file that I put together - in hopes that it will explain the dynamics of how the regulator works in this specific case. 

The Voltage to frequency chart did get clipped on the right side, but 80% is displayed and should be enough to understand the regulator interaction to speed and current in the armature winding to maintain a constant 120 volts at 60 cycles in this case. The voltage to frequency chart IS US-FULL if only the RPM's are low. The rest is a Z number generated inside the regulator to keep things set at 120 Volts.

Rich. 

Onan Voltage Regulator_model-305-manual.pdf

        The Last page 6 Bottom right corner offers some resistance tests and information covering the Generator field coil resistance and information on cleaning the slip rings and brushes. My Bad. Totally missed this information. Concentrated to much on your resistance reading. Getting to the slip rings and brushes might require removing the generator from the coach and if you attempt this - please take  a number of pictures so reassemble is possible.

GENERATOR      Checking the rotor DC resistance is particularly important before installing a new regulator. This is your chance to find out if there is a problem that possibly caused the last regulator to fail. Unplug regulator. Measure the resistance between pins 9 and 10 on the connector that plugs into the regulator. It should be between 23 and 28 ohms. A reading much lower than 23 ohms indicates a partial short in the rotor. A reading much higher than 28 ohms indicates a problem with the brushes, slip rings or a bad connection. The most likely cause will be dirty or oxidized slip rings so check them first and clean if necessary (See Slick Stick, Pg. 9). If the resistance is still high, check the brushes and connections. If possible, check the stators for grounds (See G-MAN, pg. 9). Make sure that the field flash voltage is reaching the regulator by measuring 12 VDC on pin 7 to frame ground during cranking. No voltage indicates a control board or wiring problem.

 

[chollenback]

Rich,

 

Thanks for info. Do you know if these Onon's have a Potentiometer (you can adjust voltage)? if so, where would that be.

[dickandlois]

15 hours ago, chollenback said:

Rich,

Thanks for info. Do you know if these Onon's have a Potentiometer (you can adjust voltage)? if so, where would that be.

The Module is a sealed unit and with no information on the armature winding or wiring  for the unit. I doubt that there is a pot to set. I must admit that I have not been a fan of some of the control systems used.  They know that there is a heat issue and heat kills electronics. I know that your aware of the one alternative for the module, that is in a metal case.  personally I might try one and see if it can be  mounted to a heat sink  that allows for more airflow. Thing is - is there enough room to mount one and still install the covers? 

Note! Ask if you buy a new module and that does not remedy the problem. Can it be returned.

Although it might be best just to have a shop run some diagnostics before going ahead with any more investment. 

Rich.

On 7/29/2018 at 1:13 PM, chollenback said:

 

[chollenback]

I was able to get ahold of Onan Customer service tech and he said voltage regulator is bad. I asked, "could voltage regulator test OK but still be bad"? he said yes, the capacitor can impact this. I ordered a new capacitor 220uf 400V to see if this will fix issue. I looked and I do not see where a capacitor can cause a high voltage reading from voltage regulator. Does this sound right? Can capacitor be the issue (capacitor should be here in a week).

[manholt]

One word.  Yes!

That said, if you know better than  Onan Tech.  Why call?

[dickandlois]

The real issue is the regulator is sealed / potted in a silicon type compound and it is not the easiest stuff to remove with out causing peripheral damage.. What reading did you get on the slip rings and brush resistance of the winding's listed on page 6 lower right hand corner???

Rich. 

[smilnjac]

I have the same Generator and it is putting out 170 v no load and 134 under a heavy load.   The shop replaced the Voltage Regulator twice and it keep failing and doing the same thing.  Under further inspection they tell me it is the rotor.  Bad new they don't make or stock it anymore.  Worse news if you can find one its a $1000 part.