Small generator over-voltage...

B

Bob Engelhardt

Guest
If there\'s a better site/forum for this question, please let me know.

I have an old (mid 80\'s) Sears Craftsman generator - 4 cycle B&S engine
& 120v, 1350W rated output. (Jeff - model 580.328172)

I haven\'t used it in decades so I cleaned it up & checked it out with
the intent to donate it to the Habitat ReStore.

Imagine my surprise when I measured the no-load output voltage at 134v
(with Fluke 36 True RMS meter). That dropped to 117v with a 10A load.

The no-load frequency is 62Hz, which is what the manual says it should
be (3720 RPM). That drops to 59Hz at 10A load.

The manual also claims a +-5% voltage regulation.

Seemingly unrelated, but ... the DC output is only 7v. Also, there is
1500Hz+-, 20v+- PP superimposed on the 120v 60hz output.

Note that I never before checked the voltage and I\'ve never had a
problem with it damaging loads (refrigerator, freezer, ??). So either
it\'s always been over-voltage & no-matter, or it\'s changed while sitting
idle.

Any ideas about what\'s going on here? And to diagnose & fix?

Thanks, Bob


The manual spec page:
https://imgur.com/phBAUpM
The circuit schematic:
https://imgur.com/vA6RIsa
 

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