BrianB
Generac Ultra Source 17,500 Model: 004583-0 , SN 4820634
During a power outage and using it I noticed the lights very bright.
With a meter, I checked Voltage and Hertz.
Voltage: @120 Plug= 148 , @220 = 280
Hertz: @120 outlets, I would see 59.9, and then it would jump to 120+. back and forth? @220 outlet It would never stabilize.

Any suggestions on what to check and would replacing the Voltage Regulator take care of this? From Parts list i see part # 0F9719.

Any suggestion on anything else that I should check or look at would be appreciated.
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murphy
For the frequency to jump from 59.9 to 120+ the engine would have to double its speed. At double speed the engine would destroy itself. You have a meter that is not capable of reliably reading the corrupted waveform from a generator. That makes me wonder if it can reliably read the voltage. I'm not saying that your voltage wasn't high, just that I don't trust your meter to give an accurate reading.
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BrianB
It is a Southwire unit I got a Lowes, so I won't say it is up to par with a nice Fluke.
But for most of what I do it has worked.
I have ordered a Regulator, and I was in a hurry one evening after work. So I will do another check to verify my findings. I think it was operator error. I did do a quick reference to a wall socket, and it was steady. so I will see with my next check this weekend. Living in Houston, the possibility of bad weather and no power is continuous this time of the year. Thanks
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BrianB
But back to my issue, and I hope you or someone can help.
If my Frequency is good (59.9), and stable, but My voltage is up to 148.
Would that mean that the Regulator is bad?
I have not tried to adjust it, and I have had this generator for 10yrs maybe with no issues.
How could it change with no adjustments made?
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murphy
Some of the voltage regulators were built with a plastic pot for adjusting voltage. Those have proven to be unreliable. Basically a pot is a strip of resistance material with a copper wiper that is moved over the resistance material. In your case it has been pressing on the same spot for 10 years. Vibration from the engine causes microscopic movement which will eventually "saw" through the material and ruin the pot. If that is what happened a new regulator is required. You could try adjusting it but if the resistance material has been severed you will get wild voltage changes as the pot is adjusted. It's also possible for "gunk" (anything that shouldn't be there) to get between the wiper and the resistance material breaking the wiper connection to the resistance material.
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Peddler
Sometimes sub standard meters will give a better reading with a small load applied to the circuit. As the VR ages it is not unusual for the voltage to drift. I would adjust the voltage to 120 L-N or 240 L-L with your existing VR and stop there unless it won't hold the adjustment for some reason.
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BrianB
I picked up a new Meter, nice Fluke 87V.
Remeasured Voltage and Hz.
Both legs should be at 120 L-N, measured 299 to 301VAC
Both legs Hz were at 59 to 60 the whole time.
I am measuring the voltage right at the 60amp breaker, and I pickup the Neutral at the 60amp plug.
The only thing I don't have is it tied to earth, as I am working on it in the middle of my shop. Would that affect anything?
I also seam to have lost the electric Fuel shutoff. I replaced it and it worked for a while then it stopped working.
I take the needle out and just turn the fuel off and let it run . Would this lead to a 12 volt system issue?
At the battery, I measured 14VDC dc, but at the 12vdc plug, I had 0 volts. not sure why.
What should I check next.
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UPS
BrianB;52887 wrote:
I picked up a new Meter, nice Fluke 87V.
Remeasured Voltage and Hz.
Both legs should be at 120 L-N, measured 299 to 301VAC
Both legs Hz were at 59 to 60 the whole time.
I am measuring the voltage right at the 60amp breaker, and I pickup the Neutral at the 60amp plug.
The only thing I don't have is it tied to earth, as I am working on it in the middle of my shop. Would that affect anything?
I also seam to have lost the electric Fuel shutoff. I replaced it and it worked for a while then it stopped working.
I take the needle out and just turn the fuel off and let it run . Would this lead to a 12 volt system issue?
At the battery, I measured 14VDC dc, but at the 12vdc plug, I had 0 volts. not sure why.
What should I check next.


If the voltage was even close to 300 volts with a load applied, the lights would not have been just bright, they would have burned out instantly. Have you tried measuring the voltage with the new Fluke while some possibly sacrificial load is applied?
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Birken Vogt
Come on guys, it is a common problem for this unit.

Verify that the voltage regulator is seeing full voltage (2 terminals marked SEN)

If it is and it still insists on putting out 300 volts, replace it and be happy.

Not that complicated.
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Peddler
If you have run it with the voltage output that high for any length of time the battery charge circuit which is a separate winding in the stator is probably producing 20-30 VDC and that is what is killing your fuel solenoid and anything else that is 12VDC. I would get a new VR on this thing before you do any more damage. It is pretty rare to loose sensing but as was mentioned earlier that could cause the problem as well.
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BrianB
Peddler,
I found the Diagnostic Repair Manual for this model online.
I was going to start going through it, but maybe you could list out what I need to test and values I should see on each test. I am an Engineer, but not a EE, so I understand Schematics, just not the technician to troubleshoot this efficiently.
Just a list of what and where would be very helpful, I will post the readings, and from that maybe you can give me a direction. Your help is very much appreciated.
Thanks
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Peddler
The #11S and #22s are the top two wires on the VR and they provide feedback to the VR of the output voltage. If you are getting the same voltage to these two wires as you do the #11 wire at the breaker to neutral then you have a voltage regulator problem. If you are not getting the voltage to these then you have to track down why as they are connected in the stator to the output leads. I am almost certain your trouble is the VR, common failure.
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BrianB
Peddler,
I'm looking at the wire diagram and #11s is 3rd and I don't see #22s. Could you be thinking of #44s, as it comes off the other side of the winding. I am referencing the "Run Circuit from Diagnostic Repair Manual diagram on pages 24 & 25. I tried to post a PDF of it, but don't know how.

OK, I was looking at other things in the book and came across Wiring Diagram 0G0731, and I see where #22s parallels #22 off the center of the winding.
The according to 0G0731, the VR is wired as: 11s, 22s, 4, 0, 6, 162.
"Run Circuit" Diagram on pages 24 & 25 has the VR wired: C/Ground, 162, 11s, 4, 44s, 6.1,

From My SN, how should I wire the VR 0F9719?
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Peddler
The 11s & 22s wires on the Voltage Regulator are what you need to confirm are sending voltage feedback to the VR. If they are working as they should then you would have the same voltage on 11 & 22 on the breaker and neutral. From the top depending on the orientation of the VR the wires are 11 & 22 (sensing), 4 & 0 (field), 6 & 162 (DPE) in that order.
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BrianB
OK, I was looking at other things in the book and came across Wiring Diagram 0G0731, and I see where #22s parallels #22 off the center of the winding.
The according to 0G0731, the VR is wired as: 11s, 22s, 4, 0, 6, 162.
"Run Circuit" Diagram on pages 24 & 25 has the VR wired: C/Ground, 162, 11s, 4, 44s, 6.1,

From My SN, how should I wire the VR 0F9719?
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Birken Vogt
Wire VR # 0F9719[0] as Peddler stated. These things are also cast into the aluminum SEN = sensing, FLD = field and DPE = exciter power.

The other arrangement shown on pg 24 and 25, and on the schematics before page 80, is for the older/bigger/more expensive [0]6768[0] which is not what you have, and the pins are in a different order.
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BrianB
So I plan the following.
1. Measure voltage between 11A & 22 (120VAC) and 44A & 22(120VAC)
2. Measure voltage between 11s & 22s (120VAC
3. Measure charge voltage at battery (14VDC)
4. Measure 12VDC Outlet

Am I missing something that would point to an area or item that may be causing the problem.

Thanks
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Peddler
I thought you said you had like 140-150 volts line to neutral in your original post. That points to a VR but as was explained if there was a problem where the VR was seeing the output voltage it would keep trying to raise the voltage. A voltage regulator doesn't often work intermittently but I guess it is possible.
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BrianB
Peddler, I'm not sure what has happened.
When I first started looking at the problem, I saw 148 to 150 VAC on each leg. Now I see 284 VAC 59.9 Hz.

Also, at no time did the VR Red LED light up.

Here is my data from checking everything I could.

Started Generator
Checked for red LED on VR unit. No Red light

AC Voltage Readings
Description VAC Hz
11s to 22s 284 59.8
11A to 22 284 59.8
44A to 22 284 59.8

Engine was running smooth, Voltage and Hz were steady.

Battery
Battery w/Generator Off 12.93VDC
Battery w/Generator Running at Speed 12.40 VDC
Battery w/Generator at idle 12.46 VDC

At this point I disconnected the battery.

TEST 19 (pg47)
Battery Charge Rectifier Check
BCR1 & BCR2 w/Wires off
(- Lead) to Center/(+Lead) to Outside (13A/66) 0.50 VDC
(- Lead) to Center/(+Lead) to Outside (13A/77) 0.50 VDC
(+Lead) to Center/(-Lead) to Outside (13A/66) Infinity
(+Lead) to Center/(-Lead) to Outside (13A/77) Infinity

Test 8 (pg42)
Diode D2/Resistor Test
(- Lead) to Center/(+Lead) to Base (4/Resistor Side) Infinity
(+ Lead) to Center/(-Lead) to Base (4/Resistor Side) 0.468 VDC
Resistor Ohms 22ohms

Given this information: should a new VR fix this, or do I also need a the PCB
The part numbers are 0D4409 for PCB, and 0F9719 for the VR.
At this point I would rather be safe than sorry.
What else should i look at?

And thanks for the help...
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BrianB
Hi, I'm back at trying to fix this thing.
I did all the checks listed above.
I replaced the PC Board - Part OD4409 and the VR 0F97190SRV to see if that would fix everything.

Well NO...
The motor went into a over rev condition, and I would shut it down before it got to high.
Put the old PC board back in, and it would run correctly with Idle control on or off.
The red light was not on the VR, and I only got 39VAC.

Any ideas anyone????

​​​​​​​Please...


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Bimmster
Progress?
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Peddler
make sure the DPE breaker is closed and that you are getting voltage on the excitation circuit to the VR.  Also double check your wiring on the VR as you had high voltage before and now you are just getting flash voltage.
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