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Stuart and Stevenson Generator Help?

Arkie

Registered
Last Subscription Date
08/17/2011
Guy called and has a Stuart and Stevenson Gen, model 6GD-100, 3 phase 100 kw 320 amp, 1800 rpm.
I have not seen the unit and I suspect these are the gen head model numbers and maybe not the complete rig model number.

Says bought the rig and it will only generate 180v and can run rpm and fre up and down from 58-63hz and the voltage adjustments don't change the voltage and voltage remains at 180 volts constant.

Anyone got any idea where I can find some service or owners manuals for the unit?

Or anyone care to take a guess at the electrical issue or know anything about these rigs?

I see they are still in business out of Houston, Tx, tried a phone call and had to leave a voice mail with the power generator guy and he has not returned my call.
 

Vanman

Subscriber
Last Subscription Date
07/10/2019
Re: Stuart and Stevenson Generator help?

What voltage is it supposed to be? 320 amps and 100 kw works out to ~180 volts at unity power factor, or ~225 volts at the typical rating of 80% pf.

75% pf works out to ~240 volts. That would be odd! But I have seen 90% and 70%, so... :shrug:
 

Arkie

Registered
Last Subscription Date
08/17/2011
Re: Stuart and Stevenson Generator help?

What voltage is it supposed to be? 320 amps and 100 kw works out to ~180 volts at unity power factor, or ~225 volts at the typical rating of 80% pf.

75% pf works out to ~240 volts. That would be odd! But I have seen 90% and 70%, so... :shrug:
You know that is strange that they gave me a amperage and no voltage from a name tag.:shrug:

Their main point being it's hung at 180 volts and the voltage controls will not change the voltage at all.:shrug:
 

Arkie

Registered
Last Subscription Date
08/17/2011
Re: Stuart and Stevenson Generator help?

What voltage is it supposed to be? 320 amps and 100 kw works out to ~180 volts at unity power factor, or ~225 volts at the typical rating of 80% pf.

75% pf works out to ~240 volts. That would be odd! But I have seen 90% and 70%, so... :shrug:
They emailed me a pic of the tag

220volts at 80% pf.

It stays at 180 with no load and won't move up or down with regulator adjustments.

Trying to communicate with (the horses mouth) Stuart and Stevenson in Houston, Tx. Not going great.:shrug:
 

Wayne 440

Registered
Re: Stuart and Stevenson Generator help?

...Trying to communicate with (the horses mouth) Stuart and Stevenson in Houston, Tx. Not going great.:shrug:
I'm not surprised. About 20 years ago I called them and they tried to help me, but the eventual conclusion was (this may not be a 100% accurate quote, memory fades) "I have no idea, back then we made many different models, for many different buyers, and once they were out of warranty we didn't worry too much about keeping that stuff...".
 

Vanman

Subscriber
Last Subscription Date
07/10/2019
Re: Stuart and Stevenson Generator help?

I wonder if the generator has a manual voltage control rheostat for use when the AVR fails, and he is manipulating that control instead of the voltage adjustment on the AVR itself? :shrug:
 

Steve Dawkins

Subscriber
Last Subscription Date
07/04/2016
Re: Stuart and Stevenson Generator help?

Maybe the AVR board has a coarse adjustment potentiometer, and he is adjusting the fine adjustment trimmer pot on the face of the control panel. I used to set the trimmer pot to mid-position, and then adjust the coarse pot for the desired voltage. Then the trimmer could be used to fine tune the output voltage one way or the other, if necessary.
 

Arkie

Registered
Last Subscription Date
08/17/2011
Re: Stuart and Stevenson Generator help?

I'm not surprised. About 20 years ago I called them and they tried to help me, but the eventual conclusion was (this may not be a 100% accurate quote, memory fades) "I have no idea, back then we made many different models, for many different buyers, and once they were out of warranty we didn't worry too much about keeping that stuff...".
This is what I'm beginning to suspect also.

Seems to be the norm last few years, they want to sell new or get a service contract.

The ease of availability of real good Onan generator electrical Service manuals can sure spoil a guy.

The S&S vintage gen is about 60 miles away from me, 100 F heat, it's a new old purchase, 3 electrical guys have already told them they don't know why. I'm wondering why they did not test the unit BEFORE buying?
I'm not interested in going and wasting time with no service data or even knowing if parts can be obtained.

I have enough contact info that I can hiss the owner of the gen onto them.
 

pegasuspinto

Registered
Re: Stuart and Stevenson Generator help?

I wouldn't waste my time with S&S on this old set. I also wouldn't waste time looking up any service manual. This thing is probably a straight connected simple AVR likely with 6 wires. 2 to the panel knob, two for the field, 2 for sensing. Step 1, does the generator have equal voltage on all 3 phases? Yes-go on, no, generator end may be bad. Step 2, check the rotating rectifier and ohm out the exciter stator and rotor and the main field. Step 3, replace the VR. You can go with the new version of whatever is on there, or I would just probably put in a power tronics.
 

Arkie

Registered
Last Subscription Date
08/17/2011
Re: Stuart and Stevenson Generator help?

I wouldn't waste my time with S&S on this old set. I also wouldn't waste time looking up any service manual. This thing is probably a straight connected simple AVR likely with 6 wires. 2 to the panel knob, two for the field, 2 for sensing. Step 1, does the generator have equal voltage on all 3 phases? Yes-go on, no, generator end may be bad. Step 2, check the rotating rectifier and ohm out the exciter stator and rotor and the main field. Step 3, replace the VR. You can go with the new version of whatever is on there, or I would just probably put in a power tronics.
Would you want to take a shot at working on it?
(or know anyone that would)

It's in NE Oklahoma, around Grove area I think.
 

Arkie

Registered
Last Subscription Date
08/17/2011
Re: Stuart and Stevenson Generator help?

Wayne 440;1497577[B said:
]I'm not surprised[/B]. About 20 years ago I called them and they tried to help me, but the eventual conclusion was (this may not be a 100% accurate quote, memory fades) "I have no idea, back then we made many different models, for many different buyers, and once they were out of warranty we didn't worry too much about keeping that stuff...".
They (Stuart and Stevenson) still operate the same now days. (like whipping on a dead horse)

Never did get any kind of useable info feedback from Stuart and Stevenson techs and archive dept after several attempts. (just got promises they would check but I could not get any feedback responses)

I never did go look at the old vintage Stuart and Stevenson 3 phase gen, 100+ temps and heard that several others had already been whipping on the beast and it was bought at a auction, new install.

I did ask if it was on a trailer or pad mounted. It was pad mounted.
 

ckelp

Registered
Re: Stuart and Stevenson Generator help?

have you tried cross refereeing them to kohler?
i know they have used a ton re-bagged kohlers
 

Arkie

Registered
Last Subscription Date
08/17/2011
Re: Stuart and Stevenson Generator help?

have you tried cross refereeing them to kohler?
i know they have used a ton re-bagged kohlers
I sent message to the owners that they should try such. (try to cross reference the gen section)

Try to find some gen section ID info, electrical instead of using the whole model number. It has a GM engine and a ?? gen section.
 

metallica21156

Registered
Re: Stuart and Stevenson Generator help?

Were you able to find any info out on the genset? I have a 50 kw version. I also had issues with getting power similar to your issue. The issue was on the avr. I fixed the avr and regained power. Now im just trying to address other issues.
 

Arkie

Registered
Last Subscription Date
08/17/2011
Re: Stuart and Stevenson Generator help?

Were you able to find any info out on the genset? I have a 50 kw version. I also had issues with getting power similar to your issue. The issue was on the avr. I fixed the avr and regained power. Now im just trying to address other issues.
No help at all from Sturart and Stevenson. (like whipping on a dead horse)

I never did go out to look at the rig, I heard that several other different ones had been flogging and butchering the unit electrically, so I would have had to try and figure out what they had done and not done plus cold weather and long drive to the unit.
 

metallica21156

Registered
Re: Stuart and Stevenson Generator help?

I called s&s a couple of times. They did contact their records department. They told me the records were lost in the flooding texas had a few years ago so im still on my own.
 
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