Generator Electrical Engineering Question

[dangier_VA]

mbohuntr-Fits in with what I am thinking. Many thanks-how extensive is that program?
David

 

[mbohuntr]

It's called Multisim, It will do everything from simple AC/DC to radio and digital simulations.

 

[Redneck in training]

I ran your set-up on a simulator. (Electrical circuit simulater program) If you are wired in series, the polarities are reversed, and the phases are 180 degrees off, you will indeed get 240 volts. Here's the interesting part, if your phases are off by 10 degrees, you should only see a few volts drop at a 5K resistive load. I'm not sure if the circuit will post, but at 10 degrees, or 170 degrees out of phase, you still get 239 volts.

It all depends how you connect the windings of each head together. If you connect them such a way that both are in the same direction both heads have to be 0 degrees. If you reverse one of the windings (as in the simulation) you have to offset one head by 180 deg.

 

[Soundguy]

wow.. that's odd. many ups types actually LIKE the sine wave that a genny puts out.. vs the sinusidal or stepped square wave that inverters put out. must be some noise on the waveform or a grounding issue that the ups didn't like.

soundugy

Just thought of something else-We have a 1500 watt ups for the computer, router, and satellite equipment. The last January's power outage, the ups did not like the power from the generator and would not switch over. Had not had an extended power outage before and didn't notice that. We have extended capacity batteries and they last a day or two.
In checking the 60 cps, my meter is reading a solid 60 cps on utility power. I can run the meter all around and zero in at 60 cps easily with the rpm adjustment, so I think the meter is close enough.

 

[mbohuntr]

wow.. that's odd. many ups types actually LIKE the sine wave that a genny puts out.. vs the sinusidal or stepped square wave that inverters put out. must be some noise on the waveform or a grounding issue that the ups didn't like.

soundugy

Is it possible the inverter clock pulse (Digital to Analog) runs slower on some inverters giving you a choppy waveform?

 

[hr3]

dangier_VA.. Talked with Generac today... and as I thought it is an old unit and not in there computer setup.. I told they guy your questions, #1 voltage being high 127 and 129.... He admitted yes but not that bad.. #2 that you had a bearing issue and were worried if you skipped a tooth putting it back in,, He said not to worry about skipping ..

Other comments he had were that if you had a bearing issue in one of the heads this could cause a voltage problem.. because of the rotor not running in a perfect circle. ?? another thing he said was allot of the older pto gen sets ran at 58 to 59 hertz. and that kinda makes since with the ups issue you had too.. Ups's don't like high volts but don't mind a little less hz.. He said to try setting your rpm more for the voltage but keeping the hz within limits..

Hope this helps..

 

[dangier_VA]

hr3-Many thanks for following up on the generator. The shop called today and the end bells are finished with new bearing sleeves. Will get them tomorrow and look at putting everything back together this weekend and will post results.
Did Generac give you any indication as to the year?
Thanks again,
David

 

[hr3]

Re: Electrical Engineering Question
hr3-Many thanks for following up on the generator. The shop called today and the end bells are finished with new bearing sleeves. Will get them tomorrow and look at putting everything back together this weekend and will post results.
Did Generac give you any indication as to the year?
Thanks again,
David

No he didn't sorry,, but most times when they "chuckle" it's about 20 years old,, when they "Laugh" it's over 30.. He chuckled,,,:laughing:

 

[Steve_Miller]

My educated guess is that they are identical heads wired in series but the phases have to be correct which I'm assuming you didn't fiddle with (wiring that is). The voltage imbalance is neglectable as each head may not be perfectly wound possibly causing more or less voltage on one or the other or (and this is a guess) that your resistive load is across the 240 volt. If you could put the same load on each generating head you could see if you get the same loaded voltage from each head with the identical load. Frequency within reason (a few hertz) is irrelavent to most household devices with some electronics being the exception. Good luck and thanks for all the info. I stand to be corrected if I stated something wrong.


Thanks
Steve

 

[czechsonofagun]

Frequency within reason (a few hertz) is irrelavent to most household devices with some electronics being the exception.

Exactly. If you ever been to a grid distribution center, the frequency fluctuates more or less, same for voltage.