Generac 7000EXL Voltage Problem

[David G.]

Well this is all new to me, let me see if I can make this understandable I'm not an electrician, but I do have some knowledge of it. If I unplug leads coming off stator I measure 170+ volts to ground @60 hertz. Between leads 44 & 22 I see 340+volts. Between lead 11&22 or 11&44 it's 170 volts. Lead 11 is the neutral. If I plug these back in I have little or no voltage at the outlets. 8+volts on the 120's and 16+ on the 240. Question 1. Is this the normal output voltage at the stator, to be regulated by the System Control Board, or am I losing the neutral causing the high voltage? Question 2. If so why do I lose the voltage when I reattach the wires? I have followed the neutral through the part of the circuit I can test and it's good. Could it be apart inside somewhere? This generator has only a couple hours of run time on it. Thank you very much in advance for your help! I'm pretty sure I'll never buy another generac.

[EricWood]

David, I don't know for sure, that's kind of a tough one to diagnose without the hands-on.

The 8/16 volts sounds like proper residual voltages, such as your voltage regulation is defective/shutdown.

The fact that you unplugged the 11/22/44 plug, and saw high voltages is puzzling.

Looking at the schematic and diagram, I would suggest trying to disconnect the 155 and 156 wires from the idle control transformer to the system control board and isolate them, then try running it verrrrry briefly, to see if you get the elevated voltage with the 11/22/44 plug connected. Also, just to get it out of the picture, disconnect the plug to the idle control solenoid before checking, too.

If the high voltage is valid that you are measuring, then it sounds like your regulator is going to full-field (max DC to the field via the 1 & 4 wires on the 1/2/6/4 plug). If you had isolated originally at the 11/22/44 plug, that eliminates any burden and/or malfunction of the idle control circuit and eliminates the system control board from operating.

Just a hunch until you test again, but if voltage checks out high with 155/156 isolated and all else connected, then possibly the system control board is not sensing loaded/non loaded conditions, and is shutting the voltage regulation down when 155/156 are supplying input into it.

I'm guessing you have the manual, but just in case, here's a link to where it can be viewed on line:

http://www.generac-portables.com/ser...nuals.cfm?rd=1

eric

[David G.]

Eric, Thank you very much for the quick reply.I will try these tests as soon as I have time and get back with you. One thing I forgot to mention. If I disconnect lead 11 and leave the other two connected I then have voltage at the outlets, but its 240 on the 120 receps. As soon as I plug 11 back in it goes back to the residual voltage. I am testing with a fluke 87 vom. The reason I was suspecting the neutral was past experience with my home. I lost the neutral on the service coming to the house and my voltages spiked and ruined a lot of appliances, cordless phones and other things. My expertise is dwindling swiftly.

Thanks again Eric, I really appreciate the help.

[Elden DuRand]

David:

A suggestion: Try measuring the voltages using an analog meter (remember......they're the kind with the glass front and the little pointy thing that moves when you hook it to a hot circuit)

If the analog meter shows near normal, you've got spikes that the digital meter is misinterpreting. You can try filtering the meter input with a 1K resistor in series with the testing point and a shunt .01 microfarad capacitor across the meter and see if this tames the spikes.

Anyhoo - prolly won't work but worth a shot.

Take care - Elden

[David G.]

Elden,
Thanks very much, I don't have an analog meter, but I checked it with wiggies and it seems to be a little above 240 across the leads. I guess the fluke was giving a bad reading.
Thank again for your response.
David

[David G.]

Originally Posted by EricWood

David, I don't know for sure, that's kind of a tough one to diagnose without the hands-on.

The 8/16 volts sounds like proper residual voltages, such as your voltage regulation is defective/shutdown.

The fact that you unplugged the 11/22/44 plug, and saw high voltages is puzzling.

Looking at the schematic and diagram, I would suggest trying to disconnect the 155 and 156 wires from the idle control transformer to the system control board and isolate them, then try running it verrrrry briefly, to see if you get the elevated voltage with the 11/22/44 plug connected. Also, just to get it out of the picture, disconnect the plug to the idle control solenoid before checking, too.

If the high voltage is valid that you are measuring, then it sounds like your regulator is going to full-field (max DC to the field via the 1 & 4 wires on the 1/2/6/4 plug). If you had isolated originally at the 11/22/44 plug, that eliminates any burden and/or malfunction of the idle control circuit and eliminates the system control board from operating.

Just a hunch until you test again, but if voltage checks out high with 155/156 isolated and all else connected, then possibly the system control board is not sensing loaded/non loaded conditions, and is shutting the voltage regulation down when 155/156 are supplying input into it.

I'm guessing you have the manual, but just in case, here's a link to where it can be viewed on line:

http://www.generac-portables.com/ser...nuals.cfm?rd=1

eric

Eric,
I did those tests with the 155/156 and idle control solenoid disconnected, still just residual voltage. I gave some false information in the first post. 22 is the neutral. When I did those same test with 22 disconnected I got 212 volts at the 120 receps and a little above 240 @ the 220 recep. As soon as I reconnect 22 all the voltage leaves except residual. You were right on with the fluke, I think it was showing spikes. I didn't have an analog meter but I checked it with wiggies and it was a little above 240 across the leads.Thanks again.