When I brought out my generator the other day, I started it up and measured the output voltage. It was reading 180+ volts on the 120V receptacles. It was reading 300+ volts on the 240V receptacle. I manually moved the governor down and the engine was barely running to achieve 120V. Can I assume that the voltage regulator is faulty?
Westinghouse WH7500E Generator - Too Much Voltage
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ptonsparky
Tom
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- EC - retired
Did you have a load of any sort on it? Plug a couple 1200 watt milkhouse heaters into it, measure again, and if you can measure the HZ.
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K8MHZ
Senior Member
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- Electrician
It's normal to see a higher voltage when a generator has no load. Connect a load and re-test before you assume something is wrong.
jumper
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qcroanoke
Sometimes I don't know if I'm the boxer or the bag
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Adjusting the governor will affect HZ.
Most small portables run at 3600 RPM to get 60 HZ.
Slowing it down will lower HZ also.
ATSman
ATSman
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That is correct. If my memory serves me adjusting the field voltage on some gens will change the output voltage. Like others
have mentioned it should be measured under load.
K8MHZ
Senior Member
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- Electrician
VR isn't in play when there is no load.
mbrooke
Batteries Included
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Is the meter true RMS? A none true RMS meter will read crazy stuff if the voltage isn't a perfect sine wave.
Ok, I connected a 1000W heater as a load. I'm using a Fluke 87 III True RMS meter. As a test, I checked the meter in my house receptacle and am reading 123 VAC. When connected to the generator, with the load applied, I am still reading 182 VAC. The generator bogs down a little when the heater is turned on and then gets right back up where the RPM's sound right. I checked the frequency on the output, with a Fluke 376FC clamp meter and the frequency is 61.2 hz.
There is a pot on the regulator, but from video's on youtube, it sounds like it might adjust 2 volts per turn. I don't think that there are enough turns on that pot to get me down to 120VAC.
There is a pot on the regulator, but from video's on youtube, it sounds like it might adjust 2 volts per turn. I don't think that there are enough turns on that pot to get me down to 120VAC.
ptonsparky
Tom
- Occupation
- EC - retired
Well, you have the right equipment that’s for sure!
LarryFine
Master Electrician Electric Contractor Richmond VA
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- Henrico County, VA
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- Electrical Contractor
I would first try to get it closer to 60Hz, then adjust that pot. There are multi-turn pots that use a very fine thread.
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The primary purpose of most generator voltage regulators is to control the output voltage via a closed loop system, not just to compensate for IR drop under load.
As such it needs to be able to limit the field current when running without load to keep the output voltage within the generator specs, and possibly allow that no load voltage to be adjusted to match the local system voltage.
There must be a way to supply more field current when the generator is fully loaded, and that logically requires limiting the current when there is no load.
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MTW
Senior Member
- Location
- SE Michigan
Sounds like you need a
There is a manual that gives a flow chart and resistance test for the windings, exciter and voltage regulator.
Mwe Investments, LLC known as West Pro Power Systems is an importer located in Ohio, they have one smaller unit recalled last December due to fires.
Looks like they also have a service bulletin on changing out defective regulators. Sounds like your in for one.
And a service bulletin for floating the neutral if your home GFI is tripping.
From the spec page.
There is a manual that gives a flow chart and resistance test for the windings, exciter and voltage regulator.
Mwe Investments, LLC known as West Pro Power Systems is an importer located in Ohio, they have one smaller unit recalled last December due to fires.
Looks like they also have a service bulletin on changing out defective regulators. Sounds like your in for one.
And a service bulletin for floating the neutral if your home GFI is tripping.
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MTW
Senior Member
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- SE Michigan
The manual calls for the Hz to be set at 61.5 to 63
mbrooke
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Accumulator? Amplifier? Ignition voil? Whats with the 1895 terminology :huh:
jumper
Senior Member
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- 3 Hr 2 Min from Winged Horses
mbrooke
Batteries Included
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- United States
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- Technician
New Checks
New Checks
I am back to working on this problem. I cannot find the exact AVR that is installed. I started looking at some Youtube videos, but nothing is exactly what I am in need of. One video said to remove the AVR and check the AC voltage across the + and - of the brushes. The video said it should be between 5 and 10 VAC. However, mine is measuring 27VAC. I did a resistance reading between the rotors as the video suggested. It said I should get about 45 ohms and if it is over that, then I should check the soldering of the wires to the rotors. At first, I was getting 5K+, but then I took some emery cloth to them, as suggested, and got 55 ohms. I'm not sure if these readings are for the generator that the video was testing or if this is general readings that should be good for all generators of this size.
Any thoughts?
New Checks
I am back to working on this problem. I cannot find the exact AVR that is installed. I started looking at some Youtube videos, but nothing is exactly what I am in need of. One video said to remove the AVR and check the AC voltage across the + and - of the brushes. The video said it should be between 5 and 10 VAC. However, mine is measuring 27VAC. I did a resistance reading between the rotors as the video suggested. It said I should get about 45 ohms and if it is over that, then I should check the soldering of the wires to the rotors. At first, I was getting 5K+, but then I took some emery cloth to them, as suggested, and got 55 ohms. I'm not sure if these readings are for the generator that the video was testing or if this is general readings that should be good for all generators of this size.
Any thoughts?
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