Need help figuring out generator frequency

[KBennett]

My friend just called trying to figure out why his wife's engraver won't always work when plugged into the generator. She does gun engraving at the Cowboy shoots so she needs portability. The generator is a Coleman Pulse 1850 and runs his circular saw with no problems. The governor kicks the RPM of the generator way up to run the saw but hardly does anything when the engraver kicks on.

I am wondering if this has anything to do with the 60 Hertz that is required to run most appliances and since the RPM is low (near idle) the frequency is too low to run the engraver. Do you guys know if the the generator is putting out 60 Hz at idle and if it has to be running 3600 RPM?

 

[dcoffman]

generator freq

His gen. has to be up to speed. the engraver doesn't call for enough amps for the sensor to kick it off idle and up to speed. Tell him to just let it run at speed,most double wound gens need to be running at 3600 rpm. An ONAN is quad wound and only needs to run at 1850 rpm to produce 60 cycles.

-- email address removed --

 

[gregdoerfler]

that would be right about not drawing enough amps to kick up the idle, but there should be a switch on it to override auto idle and make it run full speed all the time.

 

[klenger]

Freq is determined by enigne RPM and voltage is controlled by the generator field voltage, which (at least for my Onan) is controlled electronically by the voltage regulator. BTW, my Onan 3600 LP runs at 3600 RPM. The higher end Onans run at 1800.



I think there are three posible things that could cause the engrave not to work:



1) Incorrect freq.

2) Incorrect voltage

3) Incorrect wave shape (not likely)



You can get a meter from Camping World that will show freq and voltage. Also, generator sound can be deciving. At idle, the generator may sound like it is running slower, when in fact, it is running at full speed, but running unloaded. Without a meter of some type, it's pretty hard to tell what's going on.

 

[big jake 1]

tell him to throw a load against the generator to exite it, maybe plug a 400w halogen work light in and then try the engraver.





big jake



THE FORD GUY Oo. Oo. Oo.

 

[nickleinonen]

most mid level multimeters have a frequency setting on the meter, set it to that, and the probes into the outlets on the gen and watch the frequency on the meter...

 

[KBennett]

Thanks for the replies and confirming my thoughts on frequency.



nick, that is a good idea on the multimeter. Mine does not have that feature but I do have an oscilloscope and a 24 volt step down transformer to look at the sine wave.



I will tell him to look for the override switch to keep the generator at full speed or to try big jake's idea.