Setting engine speed on generator


Old 02-12-09, 07:51 PM
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Setting engine speed on generator

Powermate 5000 w/ the Subaru EX30, what is the best way to set no-load RPM?

I have a non-contact tach and a DMM that reads Hz.

Should I adjust for a set RPM or voltage?
I know the governor should keep the RPM's in check under load, but how much do these things deviate when under load? Should I adjust for about 130V @ no-load or just for 60Hz?

How detrimental is the cycles over the volts, meaning will appliances work more poorly on low voltage or Hz?

I would assume 3600 RPM would be the target correct?
Reason I ask is I tested it out with my Fein vac and a radial arm saw hooked together and the saw would not get up to speed, remove the vac and it did however I didn't test the voltage when this occured but will this weekend.
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Old 02-13-09, 10:42 PM
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3600 should get you 60 hz. and the correct voltage at the receptacle as far as I know. The way I understand it, 1 revolution of the armature per second equals 1 hz, so 60 per second equals 60hz, times 60 (seconds in a minute) and you get 3600 revolutions in a minute (rpm). I'd say if you have that and close to 120 volts, then I think I'd be satisfied. There may be someone more qualified than I am to add to this, so check back.
Old 02-14-09, 06:37 AM
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With no electrical loads connected to the generator (“no-load” condition). Set engine at approximately 3720 RPM. Setting the no-load speed slightly high helps prevent excessive RPM and frequency “droop,” when heavy electrical loads are applied.

Meter should read about 61.5-63.5 Hertz (3690-3810 RPM) and with load applied it will settle down to approximately 3600 RPM and 60 Hertz.
Old 03-01-09, 09:42 AM
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Update on progress.....

Would have done this sooner but my PC had a nasty virus and I had to replace hardware

I set the no-load idle to 3720 RPM, voltage at 3720 is 125V. Loaded with a Fein vac and voltage was now at 118 @ 3690 RPM. Tried to turn the radial saw on again and it would spin but not spool up, voltage dropped to 90V and RPM was 3650. Stayed like this until I turned the saw off but would not fully spool up.

Any ideas on what this may be? Brush surface is clean (ring), brush lenght is about 5/8-11/16" out from the socket. Capacitor measures correct farad.
Old 03-01-09, 01:22 PM
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I have a 3500 Yanmar that will run my air compressor. I have had several 5000 watt colemans in here for service & they will not. I'm kinda thinking the Coleman are overrated, especially when starting a heavy load. Maybe someone more familliar with generators can let us know more about these... Roger

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