# Output voltage?



## wml52 (Feb 21, 2014)

I have a 17 YO going on 18 YO Generac mdl: PP5000 (5000 running watts/6550 starting watts) brushless genset powered by a 10HP Tecumseh.

The generator ran through a 6-circuit transfer switch, which powered just the essentials, well pump, furnace, fridge and a few lights. This set-up worked ok but during extended power outages showering with ice-cold water in the winter wasn't exactly a joy.

I recently did away with the transfer switch in favor of an interlock breaker so I could managed the loads and choose which circuits I wanted to run and when i.e.: the electric water heater.

After fine tuning the generator it fluctuates between 121-124 volts output on L1 and L2 with no load @ 3650-3670 RPM and with the 3500 watt resistive load of the water heater it drops and fluctuates between 115-118 volts @ 3550-3570 RPM. I then pushed the generator a little more by adding another 1500 watt resistive load and the voltage dropped an fluctuated between 108-111 volts for both L1 and L2.

This appears to be the best I could dial it in and wanted to know if this sounds about right? Any info would be appreciated.

Bill


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## aandpdan (Oct 8, 2012)

What RPM was the generator running at when you added the extra 1500 watts?

I don't think your governor is sensitive enough. You really need to run around 3600 RPM for 60 hertz. It's as/if not more important than the voltage.

A 10% tolerance on voltage from your POCO can happen. 108-132 volts or so, 120 is nominal.


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## wml52 (Feb 21, 2014)

Finally got some time to work on the generator. I did a little digging and found the spec sheet for my Tecumseh engine used on the generator. According to the specs the no-load speed should be set at 3750 RPM.

I readjusted the no-load RPM to 3740 RPM and applied various loads, here are the results:

No load 3740 RPM 126.0 Volts @ 62.3Hz
1600 watt resistive load 3725 RPM 122.6 volts @ 62.0 Hz
3500 watt resistive load 3545 RPM 116.5 volts @ 59.0 Hz
5100 watt resistive load 3475 RPM 106.6 volts @ 57.9 Hz 
Oil fired Furnace 3740 RPM 126.0 volts @ 62.3 Hz
1/2 HP well pump 3735 RPM 122.9 volts @ 62.2 Hz

Couldn't dial in the governor any better, if I adjusted the governor to give me 3600 RPM with a 3500 watt resistive load it would over shoot 3750 RPM when the load was removed. Considering the 3500-watt load is my water heater and a managed load I didn't want to push the RPM any further. The majority of the time the generator will be running lights, furnace in the winter and fridge with the occasional well pump kicking in.

Your thoughts?


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## aandpdan (Oct 8, 2012)

They're pretty good. 

You really shouldn't be running the generator at near max load for any length of time so you'll probably tend to be in the 62-59hz range mostly.


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## KRE (Nov 29, 2011)

wml52 said:


> I have a 17 YO going on 18 YO Generac mdl: PP5000 (5000 running watts/6550 starting watts) brushless genset powered by a 10HP Tecumseh.
> 
> The generator ran through a 6-circuit transfer switch, which powered just the essentials, well pump, furnace, fridge and a few lights. This set-up worked ok but during extended power outages showering with ice-cold water in the winter wasn't exactly a joy.
> 
> ...


 You have a droop issue. Either the spring is weak, it's in the wrong whole or the linkage is binding. When it is correct, you can over ride the linkage towards idle and when you release, it will return to speed promptly and will hunt for speed 1-3 times max. Any more or less than that and you have the droop setting wrong. Governor adjustments are a very Simple fix. Running the unit at full rated load is not an issue as long as it can cool it's self, properly.


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