Community Forums

Bilito · 11-20-2012, 11:20 AM

re my posts regarding buzzing in the elect panel under the bed.

I took my new Kill-A-Watt meter out to the rv and plugged it into the 120V outlet with the gen running and it was reading 163 volts AC. I did that on two outlets and it read the same, this cannot be, so I got my handy dandy multimeter out and set it to ac volts and stuck the prongs into the outlet, it also was reading 163 volts.

What is going on? This can not be right....

Dr4Film · 11-20-2012, 11:35 AM

Please post the year, make, model of your RV an also the make and model of your generator.

Also let us know if your transfer switch is the device mounted under the bed you are referring to that is buzzing.

Some generators have voltage regulators and others do not. Need to know more information before trying to help.

Dr4Film ----- Richard

Bilito · 11-20-2012, 11:48 AM

Quote:

Originally Posted by Dr4Film

Please post the year, make, model of your RV an also the make and model of your generator.

Also let us know if your transfer switch is the device mounted under the bed you are referring to that is buzzing.

Some generators have voltage regulators and others do not. Need to know more information before trying to help.

Dr4Film ----- Richard

It's a 1992 32 ft Silver Eagle on an Oshkosh chassis with a big ford gas motor

The gen is a Generac NP66G and according to my manual there is an Electronic Voltage Regulator in the control panel with a Voltage Adjust POT inside. It states that at 62HZ the voltage should read 124 volts, if incorrect slowely turn the adjust pot until ac voltage is correct

I guess the first thing is to find that panel, I just had the cover off the control panel to change the two 30 amp C/B's and it was full of wires and I do not recall seeing anything back in there that looks like the drawing in my manual

Bilito · 11-20-2012, 12:09 PM

Quote:

Originally Posted by Bilito

It's a 1992 32 ft Silver Eagle on an Oshkosh chassis with a big ford gas motor

The gen is a Generac NP66G and according to my manual there is an Electronic Voltage Regulator in the control panel with a Voltage Adjust POT inside. It states that at 62HZ the voltage should read 124 volts, if incorrect slowely turn the adjust pot until ac voltage is correct

I guess the first thing is to find that panel, I just had the cover off the control panel to change the two 30 amp C/B's and it was full of wires and I do not recall seeing anything back in there that looks like the drawing in my manual

This picture is what I see with the control panel removed, the drawing is a pic of the page in the manual
The only thing I see in the panel is a tiny blue screw that looks like it can be turned. It does not look like the drawing at all
????????

Sportscoach · 11-20-2012, 01:46 PM

Quote:

Originally Posted by Bilito

I took my new Kill-A-Watt meter out to the rv and plugged it into the 120V outlet with the gen running and it was reading 163 volts AC. I did that on two outlets and it read the same, this cannot be, so I got my handy dandy multimeter out and set it to ac volts and stuck the prongs into the outlet, it also was reading 163 volts.

What is going on? This can not be right....

It can be right. If you have a generator with an electronic voltage regulator, the output transistor (IGBT or MOSFET) may be blown = shorted. When shorted, it supplies the maximum current to the rotor windings and 165 volts AC is almost exactly the voltage you will see for many Onan models. I've seen it myself on an 6.5 NHD. I don't know about your Generac, but it's certainly possible. The VR will turn the current on/off to hold the voltage constant, and if it can't turn off, you'll get around that voltage.

I doubt if turning the voltage adjust will lower the voltage.

wa8yxm · 11-20-2012, 01:52 PM

You used two different meters and both showed the same result... now if you want to be 100% sure take those same two meters to a known voltage source and confirm they read correctly but..

I believe Sportscoach, And this is the field I traied in (Electronics) he more or less hit it on the head with one minor alteration.

Even if it does NOT have an electronic voltage regulator. (Older genrators had a different type) That's the problem, the voltage regulator is not regulating.

Sportscoach · 11-20-2012, 02:01 PM

Quote:

Originally Posted by wa8yxm

Even if it does NOT have an electronic voltage regulator. (Older genrators had a different type) That's the problem, the voltage regulator is not regulating.

I agree - test the meters. It should be easy - find any AC socket. As to the older gens - most of them I'm familiar with use either a transformer for regulation or adjust based on the RPM of the engine. It's pretty hard to get those older gens up to 165 VAC, but that number just jumped out at me as matching the number I saw when my electronic VR broke. It's also possible to get numbers like that if the wire to the VR is broken (the wire that monitors the output voltage), so I'd check any connections in the wires to the VR.

Bilito · 11-20-2012, 02:13 PM

Quote:

Originally Posted by wa8yxm

You used two different meters and both showed the same result... now if you want to be 100% sure take those same two meters to a known voltage source and confirm they read correctly but..

I believe Sportscoach, And this is the field I traied in (Electronics) he more or less hit it on the head with one minor alteration.

Even if it does NOT have an electronic voltage regulator. (Older genrators had a different type) That's the problem, the voltage regulator is not regulating.

In order for me to get a small screwdriver in there to adjust the POT, it scares me to death to try that with it running and all those wires in there, so I shut it all down and turned the POT to the left, then started it up again, the voltage went down to 157, (BTW the little red LED by the adjuster was on steady) so we did it all over again and the volts went down to 156, the LED steady, tried it again but this time I turned the POT the opposite direction and the LED started to blink and the Gen never came on line, after a min or two it shut itself down before it came online?????????? I may have run out of gas, which is probable, the tank is way below 1/4.

I put about a gallon in it a few days ago because I was running the gen and fixing a stuck choke and ran out of gas

I have not checked the volts at the outlets with it plugged into the shore power, nor have I checked my two meters against each other in the house to see if they read the same in there

clyon51 · 11-20-2012, 03:50 PM

The LED just lets you know excitation has taken place and voltage is being generated/regulated. I've adjusted my Generac before and it's very easy. Most of those wires are 12v control wires but you never take a chance unless you know for sure. I just use a long screwdriver and make sure I'm insulated. Turn the screw clockwise to reduce voltage.

Muddypaws · 11-20-2012, 04:09 PM

The rule when working on any live electrical system is to never ever stick both hands in there. Put your other hand in your pocket (seriously). Wear rubber soled shoes so your body doesn't become the ground path. If you're using a long screwdriver wrap tas much of the metal shaft as you can with electricians tape.

Not a good idea to droit while nobody else is around either.

Bilito · 11-20-2012, 04:12 PM

Quote:

Originally Posted by clyon51

The LED just lets you know excitation has taken place and voltage is being generated/regulated. I've adjusted my Generac before and it's very easy. Most of those wires are 12v control wires but you never take a chance unless you know for sure. I just use a long screwdriver and make sure I'm insulated. Turn the screw clockwise to reduce voltage.

Clockwise to lower it, that's the opposite of what I was doing.
Are you supposed to adjust it while it is running?
Do you think I can get it down to 120 volts?
What do you think was making that light blink?

wa8yxm · 11-20-2012, 06:00 PM

I have a very nice INSULATED screwdriver, IN fact I have several (most electronics types do, electricians not so many) Forget where I got the one I'd loan you.. but Radio Shack used to carry some nice insulated NON METALLIC ones (or very little metal)

They are used in tuning the coils in radios and televisions. A couple of the ones I have should (in theory) be good to a few thousand volts. never tested that theory.

Bilito · 11-20-2012, 07:29 PM

Quote:

Originally Posted by wa8yxm

You used two different meters and both showed the same result... now if you want to be 100% sure take those same two meters to a known voltage source and confirm they read correctly but..

I believe Sportscoach, And this is the field I traied in (Electronics) he more or less hit it on the head with one minor alteration.

Even if it does NOT have an electronic voltage regulator. (Older genrators had a different type) That's the problem, the voltage regulator is not regulating.

I just tested both meters in my house wall plug both are right around 122 volts

clyon51 · 11-21-2012, 06:26 AM

You could have a frequency problem, so I would first check that:

The output frequency of a generator is measured in Hertz, which refers to the number of alternating current (AC) cycles per second. The standard frequency for electrical service in the United States is 60 Hertz. The RPM of the engine that powers the generator is the factor that determines the frequency, and the generator owner's manual contains instructions on how to adjust the engine speed. Before you can adjust the frequency, you need a way to test it. High-end multimeters include this function, but a cheaper and easier way to measure frequency is to use a Kill-A-Watt-type household load meter.

So check to make sure the hertz is 62 with NO load. If it is higher, then you need to lower engine RPM.

Once hertz is at a proper level, check the volts....124v would be perfect. If necessary to adjust, keep the VOM attached with engine running and warm. Now adjust the POT slowly to 124v. If counter-clockwise lowered before, then start that way first.