Old AC generator voltage regulation.

[WA1LGQ]

   I have an old Onan 1.5 kw gas powered AC generator that I just got running, needed a carburetor dissasembly and cleaning. But it seems that the governor is busted. It has a governor that runs of the camshaft or something, I don't really know much about these things. I was told that this system had a tendency to crap out. I wonder if anybody knows of an electronic regulator circuit that I could build up for the thing. Right now I have the idle adjusted so that no load voltage is about 127 and with a 900 watt load it drops to about 105, so its reasonably usable, but not great. I don't want to use it when its putting out 150+ volts, that could burn out my radio stuff.

............Larry

[KA2DZT]

My generator broke the mechanical governor about 10:30 Sunday morning on Field Day.  It all of a sudden put out real high voltages to the stations.  Blew some fuses, smoked some of those MOV power strips.  The MOV's shorted and took out the fuses.  It did some damage to a K3 rig, not sure how much.  I think everything else survived.

I've been working on a outboard mechanical/electrical control to bypass the governor.  Haven't finished it yet.

Fred

[W7TFO]

I've seen where a crafty guy had the same problem, he took a automotive alternator regulator (Ford, IMHO) and adapted it:  Rectified a genset output sample, dropped it down with a big slide resistor, and fed the regulator.  Hooked the field circuit up thru a big pot and worked like a charm.

73DG

Oops...I at first read you had a voltage regulator problem.  Now it seems it is really a governor problem.  Maybe count the teeth on the ring gear (if it has one) for a reference freq, or just sample the output into a resonant ckt to pull in a solenoid on the throttle.

[WQ9E]

I would also investigate adding an external circuit to protect the gear from over voltage; maybe a circuit to activate a mechanically latching relay to open the line when the output voltage exceeds 135 volts or so.   Enough voltage to "fire" a MOV rated for 120 volt AC use is going to be well over that which makes gear unhappy.  MOVs do some good for voltage spikes but don't offer any protection against a "loose" regulator that lets the voltage creep up to 150 V RMS or so.

Although Onan made some good stuff, with modern 2KW generators selling in the $300 range new I wouldn't put too much effort and money into an older 1.5 KW unit-especially given the price of repairing anything damaged by it.

[WD8KDG]

Good chance the governor was a centrifugal device. As the engine attempted to increase speed the carb was throttled back & visa versa. A machine shop could build another, using the old parts as a template.

Cost$$$$$...........

Craig,

[AJ1G]

You might want to post your question on smokstak.com - someone on here pointed me to that site, sort of like an amfone.net for the antique engine folks, they also have subforums that deal with modern small engines, generators and the like.

Someone on there reverse engineered an older Generac VR.

[ve8xj]

I have a 2 cylinder horizontally opposed   Onan CK series from the late 50's probably very similar to yours. Used it on a sawmill I built way out in the bush on my trapline. It has the simplest,and most reliable  governor  system around once you get them tuned up. Not much to go wrong. Fly weights might be warn. It still is out in the bush so I can't look at it. Onan was taken over by Cummings international but still have a lot of parts for that series,though they usually ask a lot. Found this Onan parts dealer on Ebay  http://motors.shop.ebay.com/partsatcurtis/m.html?_nkw=&_armrs=1&_from=&_ipg=&_trksid=p3686

Maybe he has the parts your looking for.

[ashart]

If you equip your generator system with an old-fashioned "fly-ball governor", the one with the three suspended and revolving brass balls that move under the influence of a centrifugal force proportional to the speed of the generator, and if the system is indoors and the regulator fails, you will learn the true origin of the old saying "going balls to the wall".

-al hart, w8vr

[N8ETQ]

My old kohler uses the "Govenor" to set the freq. 60cy. it
keeps the engine running at 1200 rpm. The voltage
"Regulator" is a couple W/W R's, one with a slider to set
voltage at 115 AFTER YOUR AT 60 CY.  I never really had
to mess with the regulator but the govenor is a PIA.
My engine is 4 cylinder 4 stroke water cooled job that
starts like a model T Ford. Also a PIA!

Manual here:
http://www.oldengine.org/members/frank/kohler1.htm

GL

/Dan

[KM1H]

What about feeding a couple of CVT's?

I have a 5KW generator which has that spring loaded arm that controls the carb but its iffy at best since it was new in 85.

I feed the main panel direct at 240V and use a 1000va CVT at the "office" desk with the 2 PC's and a 500va in the basement to run the SSB rig barefoot and some FM crap if needed.

Carl

[The Slab Bacon]

It is very important to fix the governor on that rig. It maintains a constant engine speed as the load conditions vary. As the load increases it kicks the engine in the ass, as the load decreases it throttles it back. It is very important to maintain constant engine speed in an engine driven generator. It controls both the outpoot voltage and the frequency as well. Without a governor that rig is worthless, and any attempt at electronic voltage regulation is just a gypsy patch at best. It would drive the regulator nuts if the engine speed was constantly changing. (As the regulator calls for more the increased load will cause the engine to slow down defeating the purpose of the regulator.

Onan used to be pretty good about having repair parts for their older models. they may not have a complete governor assy, but they should have the small parts needed to repair it.


Dan (ETQ),
                that old Kohler is way kool. I have seen them at antique gas engine shows, and no one wants to sell them. That little bitty 4 holer is a cute little engine.
It's a shame they're only 1.5kw. But they are a desireable collectable.

[W1ATR]

If you equip your generator system with an old-fashioned "fly-ball governor", the one with the three suspended and revolving brass balls that move under the influence of a centrifugal force proportional to the speed of the generator, and if the system is indoors and the regulator fails, you will learn the true origin of the old saying "going balls to the wall".

-al hart, w8vr

I remember a conversation on these terms with a group on another forum some time ago. "Balls Out" was more associated with flyball governors as the term did show up on a google books search in texts before 1950, and ment the engine was running at full tilt with the flyballs slung all the out horizontal. "Balls to the wall" does show up in plenty of texts regarding military pilots however. The throttle levers generally had a ball knob on the top and when they pushed the throttles all the way to the firewall, it was considered running the bird "Balls to the wall"

[WA1LGQ]

Thanks for the tips. I think you are right with your comments about engine speed Slab. I will look into finding the governor parts. That's probably the best thing to do. The engine is Briggs and Stratton, so might be able to get the parts. I noticed that when it was putting out 120V, the freq was 60Hz. Above or below that voltage, the freq was not 60Hz. maybe I can work with that somehow. I'm not going to get too crazy about this though, right now the way it is set it is somewhat useful, and a replacement generator of similar power is not all that expensive. But the thing is a cool old buzzard 60's vintage green painted beauty. Its probably underrated too. That Kohler looks awesome, way cooler than mine. Once I did try a voltage controlled transformer on it, but it smoked it, and blew up the MOV's.......BANG!

............Larry

[Opcom]

Brushless alternators with a brushless exciter of the kind where it has a rectifier across the exciter rotor and a capacitor across the exciter stator will increase the voltage as the RPM increases and decrease it as the RPM decreases. They depend on an accurate governor to make a steady voltage. I had one in which I set to 62Hz (127V) no load so that with full load I got 117V 60Hz.

[The Slab Bacon]

Hmmmmm................. It is not common for D.W.Onan to use B&S engines. I think they may have had a few, but not many, and prolly a lower end model. They used to manufacture their own. The Onan brand engines themselves were high quality units, sometimes found on other high end pieces of equipment that bought them from Onan.

If you ARE dealing with a B&S engine, I doubt that is an Onan power plant. Keeping the old rule of thumb in mind: "It takes 2 shaft horsepower to generate 1 Kw pf electricity" (At least in small power plants) You prolly have a 3 1/2 - 5Hp engine. Parts should be readily available for it.

[WA1LGQ]

I did not see a B+S nameplate, but it just kind of looks like one of their motors. There is a number stamped into the cover and I used it on the search section of the B+S site and did not find an exact match, but damn close. I should try the Onan site again. I looked there already but could not find the exact model.......LB

[W2PFY]

If you can't find parts then maybe a cheapo battery charger hooked up to it charging a battery with and inverter hooked to the battery might be the answer for a low power  supply? The charger won't care if the voltage is somewhat high or not at 60 cps. This way you will always have 60 cps and the system depending on the inverter may handle a large varying load.

[K9PNP]

Just out of curiosity, what is the model number of your Onan?  I have a 1967 model 2.5LK-1R with an internal generator issue not related to rpm.  IIRC, the older Onans ran at 1800 rpm for frequency of 60 cps.  And the manual shows very little about the generator portion.  I agree on the comment that it was unusual for Onan to use B&S engines.

[W7TFO]

Some smaller Kohler gensets used an engine that resembled a B&S.

73DG

[WA1LGQ]

Mitch, the model number is 105PC 1P/1B.

[The Slab Bacon]

Some smaller Kohler gensets used an engine that resembled a B&S.

73DG

Dennis,
           that was most likely a small Kohler engine. They did make them down as small as 4HP, but the little ones are pretty rare. I have one genset that uses a Kohler 10HP,
(not a Kohler genset) But..............It is one of those 3600 RPM screamers. My Main standby genset here is a 1948 US Power and Light 5Kw "Light Plant" It uses a 2-cyl Hercules BXB flathead engine. 1800 RPM and water cooled with a huge radiator. It kinda looks like a small tag-along welder. It has run 24-7 for as long as a week without ever complaining.