Generator Electrical Engineering Question

[Transit]

One thing I am not reading is what the voltage was before you disassembled the generator, maybe the 127-129, 250 is normal.

Bill, not everyone has access to an O-scope, nor the ability to use one. Even better yet, a Fluke 434 power analyzer.

 

[Sootgrinder]

You are less then 5% high, you are within the parameters that your utility company has to provide so don't worry about it. When you take it back apart make sure that you are 180 out when the gears are meshed together all the way, with this type of gear the two will be out of time when the teath are first engaged but when it slides all the way down the shaft rotates and changes the timing.

Soot

 

[dangier_VA]

Transit-We ran the generator last January for 5 days straight (off at night), and as I recall the readings were 124/125 volts per each leg and 240 volts combined.

hr3-If memory serves me right, the no load voltage was around 127/128 in January. The generator (alternator) is brand named Niagara, with Generac in small letters on the bottom of the name tag. Model # 5403-3, serial #0161083.

Many thanks for the responses. I only moved the gears what would amount to two teeth from one power head to the other. Would that small adjustment caused the increase in voltage? Should the voltage regulators maintain a setting of 115 volts per power head as listed on the data tag? Should the regulators be checked?

I think I am going to look into brush end bearings with a larger diameter and have the end bell bored out for proper fit. Just have to get the old bearing off. No puller space, so modifying a auto alternator pulley puller and hope it will have the strength.

 

[dangier_VA]

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]

If your two waveforms are not in phase, your voltage and power will suffer. I would talk to a generac tech and get their input.

 

[firedog]

If your two waveforms are not in phase, your voltage and power will suffer. I would talk to a generac tech and get their input.

Ditto... I'm thinking you are out of phase.

 

[KWentling]

I think I am going to look into brush end bearings with a larger diameter and have the end bell bored out for proper fit. Just have to get the old bearing off. No puller space, so modifying a auto alternator pulley puller and hope it will have the strength.[/QUOTE]

Just have the machine shop (preferably a motor shop) sleeve the housing back to the original bearing size. We do that all the time at the shop I work at. Make sure they use a bearing chart and get the proper fit. A C3 bearing should be a push in fit with no rocking or turning in the housing. Your talking of center punching the housing fit made me cringe.

Lots smarter generator people here than me. I've worked in motor shops for the last 30 years as a machinist and I don't remember ever seeing a generator like yours come through the shop. We have a generator guru at the shop. If I can think of it I'll question him about it. Cycles can be checked with an electric clock plugged into the generator compared to a watch second hand. Done that before to get engine RPM correct on the farm. Then adjust the voltage regulator to get the voltage right.

Kim












Kim

 

[Skyco]

I'm wondering what you are measuring the voltage with?
Many meters will read AC voltages all over the place if it isn't a really pure sinusoidal waveform. Most generators I've looked at with a scope aren't that pure and clean.
Do the generators even have any sort of voltage regulators? Some don't.

 

[dangier_VA]

Checking the power voltages with a Fluke digital meter. Double checked with an older Simpson analog meter. Both were within 2 1/2-3 volts.
Appreciate the responses.
David

 

[Rob-D]

zzvyv6-Nope, by power/cps meter.

KWentling-The generator gets the 220/240 volts from the paralleling of the power heads with the wiring (one leg from #1/one leg from #2) to the breaker. Would it make sense to get the max use of the magnetic field? The other leg from each power head is grounded.

Craig Clayton-I have pictures of the complete unit (attached). Did not take pictures when it was broken down. I may have to go to a larger bearing and have a machine shop bore out the end bell. Right now I have about .20 slop.

Probably better off having a sleeve inserted. The housing might not have the strength if you bore it out to the next bearing size. The housing can be bored out to, say, .050" oversize and a sleeve inserted and locked in with Lock Tight Sleeve Retainer. If you go to a larger bearing you have the armature shaft diameter to contend with also.

Rob