Generac rotation ??

[Stans]

What direction would this puppy need to be driven, clockwise or counter-clockwise? From the "facing the pulley" direction.
Stan in Kimberley

[Steve Dawkins]

If you don't see an arrow anywhere that indicates rotation, it's probably bi-directional. Single phase generators generally don't care which direction they spin.

[BTPost]

Originally Posted by Stans

What direction would this puppy need to be driven, clockwise or counter-clockwise? From the "facing the pulley" direction.
Stan in Kimberley

Pull the end plate and see if the brushes have an offset from perpendicular.
If not, then it doesn't matter. If so rotation is away from brush face...

Bruce in alaska

[Gunny]

Shouldn't make any difference with that machine. Spin it either way.

[MBusch]

I see there is cooling fins on this generator. If I'm not mistaken air should be pulled in and exhausted out back. The fins are generally angled and scoop air and discharge the air in the center. To make sure check a car's generator. to direction verses cooling fins angle.

Myron in Minnesota

[John Newman, Jr.]

I've got one that looks very similar to that - mine is 4000 Watt 110 / 220 and has a Sears tag on it, but the Mfg'r code on the tag indicates Generac.
Cast iron pulley / cooling fan with straight blades. Perpendicular brushes. Will go either way.

[Arthur]

Hello John Newman,

I have a Generac that seems to be like what you have. Mine is an RV unit and is also belt driven with what I call a micro groove belt. It is 4000 W and mounted vertically.The engine pulley is cast iron about 8 in.dia., the alternator pulley is also cast iron and 5 or 6" dia.. The belt seems to be too tight and the adjustment is backed off all the way.

This info. is on my belt,-- 10 RM Poly V Belt, Raybestos Manhatten, 36624

Would you mind checking your unit for belt size and Rpm of unit? My unit model no. 6120-1.

If I can help in any way, let me know. Arthur

[Stans]

Hi Arthur....rpm as posted is 3600. I plan to drive it with a Wisconsin EY27W which is rated at 4.9 hp @ 1800 rpm driven with a 1 2/2" pulley on the motor and driving the 3" pulley on the gen head should equal 3600 rpm. Right???

The brushes are straight on to the shaft, and the vanes are straight out from the center of the pulley so either way should be good.

Does anybody have any idea of that white box (it is resisting my gentle efforts to remove it) is in the pic? I am wondering if it is a 12 v dc junction and this unit will produce 12v dc?
Stan

[Stans]

I meant 1 and 1/2 " pulley on my last post.
Stan

[Jim McIntyre]

Originally Posted by Stans

Does anybody have any idea of that white box is in the pic?

Looks like a connector with mated plug, which probably has a few electronic components (such as rectifiers) encapsulated in the yellow stuff.

[Stans]

You're right, there's some lumpy stuff under the yellow gunk (now fairly hard) that's probably components. In case anyone is interested, this is a fairly well made unit. Almost 50lbs, good beefy bearings, very well made. It should stand up to long service and be easily servicable if spare parts are still available. Not bad for a donated unit even if it will only put out 20 amps @110v.
Stan

[Arthur]

Originally Posted by Stans

I meant 1 and 1/2 " pulley on my last post.
Stan

Stan, your drive setup is different from mine. If you are planning to run the engine at 1800 and the gen at 3600 rpm,I believe you'l have to have the engine pulley twice the dia. of the gen pulley.To me,that ratio seems a little high for a single belt pulley to carry,especially a 4 kW gen. Most of the time I get all mixed up trying to get ratio's right,but maybe someone will come in and straighten us out. Arthur

[Stans]

You too Arthur???? I always get mixed up with those things. I do know that somewhere along the line it has to be 2 to 1. It's only a 2kw gen head though and I won't be loading it up fully anyway, because it's going to be the emergency backup for a ham radio station. I am a member of our provincial emergency amateur radio group and need something to keep me going in a power outage.
Stan

[Steve Dawkins]

Hi Stan,

If the pulley on your generator is 3" diameter and must turn at 3600 rpm, then the pulley on your engine should be 6" if it is going to turn 1800 rpm. When powering a generator, the rule of thumb is 2 HP per kilowatt. Since your engine is rated at 4.9 HP @ 1800 rpm, that is close to a perfect match for your 2400 watt generator @ 3600 rpm.

The "white box" is a connector and mating plug like Jim M. said. It's part of the voltage regulator/exciter circuit. It wasn't designed to provide 12 volt dc power for external use.

Steve

[Stans]

thanks Steve! The Wisconsin EY27W is actually rated at 7.9 hp at 3600 rpm or 4.9 hp at 1800 rpm and I just thought it would be quieter, and subject to less wear and tear at 1800 rpm. I wonder how it would stand up to sudden loads at the lower rpm though because usually there's less torque than at the higher rpm.
Stan

[Steve Dawkins]

Your engine probably won't be much quieter at 1800 rpm than it would at 3600, but the pitch of the noise will make it seem quieter. You're right, there will be less wear at 1800 rpm.

I'm more of an electrical guy than an engine guy. I'm not sure about the power curve on engines, but I would think your engine would have a tougher time recovering from a sudden heavy load if it was running at 1800 rpm. It seems like there would be less torque at the slower speed. Hey gear heads, the electron chaser needs some help here!

[John Newman, Jr.]

Engine load recovery:
Think of your car or truck with the cruise control on and set for 40 MPH. The available HP will be able to handle the various inclines that you encounter on your drive, but will lag a bit at the bottom of each hill. At 70 MPH there will still be a little lag, but it will recover quicker. In each case though, the variations are gradual. If you were to instantly go from a 'downhill' mode to a 45 degree 'uphill' mode (Yes that is extreme) it would take quite a bit longer to recover. Your generator is placing a similar load on this engine. If you go from a no-load to full-load with one flip of a switch, there will be more recovery time required than if you add or subtract a percentage of the rated wattage incrementally. So if you are running along at about 60% (in your case that would be 1200 watts) and switch on another 100 watt light bulb, it should be able to absorb it without difficulty. You mentioned using this set-up for emergency radio power. Is there a substantial increase in electrical consumption when you key the mike? How much difference is there between Receiving and Transmitting?
You also might try experimenting with different engine / generator pulley combinations. If you select pulleys that will let you run the engine at 2000 - 2200 RPM (5-1/2" and 5" engine pulley respectively), you are still better off than going 3600, and it will improve your position on the HP / Torque / RPM curves.

[Wayne 440]

If you have the HP/torque curves for your engine, set it up at or slightly less than what ever speed the unit makes the most torque. You and the engine will be much happier with the results.

[Stans]

Thanks Wayne & John....I've just posted a question in the small engine section to see if anyone can help me find the power curve info for this engine. Your advice makes a lot of sense as I'm wanting to run the engine at the slowest feasible speed for obvious reasons. My son keeps telling me his Infinity (car) is "designed" to run at 6 or 7K rpm and I'm constantly telling him that it's wear rate is twice that at 6K rpm as it is at 3K rpm. As usual he doesn't listen. Sigh.
Stan

[Wayne 440]

For ham radio power, I would go for about 2400 engine rpm. I have a 3.5 kw single cylinder Kohler 1800rpm set and on CW you can see every power stroke on a service monitor. Use cast iron or steel pulleys for added flywheel mass. Drop me a line if you care to talk more about ham radio power solutions, I have considerable experience with commercial and "ham" installations.