genny belt drive

[VW cat]

Has anyone out there used a positive drive belt or notched belt, such as an automotive timing belt, to double the speed of a generator. Just trying to think of an easy way to double the speed of my generator through the drive.

[Putte]

Hi VW cat.

I did try belt drive with cover for the belt on a induction generator on a small windmill in hard wind an rain it spun like crazy even with a cover its hard to keep water out. that said it does work but i would not try it again. thats my experience.

Putte.

[nothing to lose]

Perhaps something was wrong with your setup? What was the problem, slipping? I have several times had flat belt driven aircompressors sitting in the rain and running. I never noticed a 5hp 60Gal compresser slipping on me.

And auto belts get wet all the time, lots of HP being moved long that serpentine belt driving all those various units at once, power steering, water pump, altenator.

I think you'd still lose some power to the belt drive, but wet shouldn't matter if properly tensioned and correct belts and pullies. Everything alse is gonna get wet anyway.

Proper tension is a key also, anytime you install a new belt it stretches in use pretty quick and should be re-adjusted before long. Self tensioning idler pullies might be able to do that, but if a manaul adjustment expect it to get loose in a few days or about 100-200 miles and need re-adjusted.

[Putte]

I do agree with you nothing to lose my setup wasnt perfect if i had to mutsh tension there was a real powerloss and i had problem getting it started in low winds so i had to loosen it very little but when raining and really hard winds it would slip and as it slipped the belt would "groin size" and fit even worse so i dident find any reason to continue.

Putte.

[Ungrounded Lightning Rod]

I did try belt drive with cover for the belt on a induction generator on a small windmill in hard wind an rain it spun like crazy even with a cover its hard to keep water out. that said it does work but i would not try it again. thats my experience.

(The original question was about a cogged belt, which wouldn't slip from water.  I presume you're talking about an ordinary V-belt.)

V-belts should not slip when wet if properly tightened.  But there's a little trick:  New v-belts have to be worked in.  You have to let them run in under load for a half-hour or more after instalation, then tighten them again.  Otherwise they will start to slip under load some time later (and wear out rapidly after that).

Some of it is that they need to be run in order to properly seat in the pulleys.  Some is that they have to wear off the factory shine.  I think there's also a bit of size change of the belt itself from final curing under load flexing.  All of this is pretty much done in a half hour or so.

(One nice thing about V-belts is that they TIGHTEN as they warm up under load.  This tends to make MINOR misadjustment self-correcting.)

[tecker]

  If you keep the pulley large enough you can improve the slip It's going to slip a little but don't use a small pulley the belt will hold better if it dosen't have to turn the corner sharply.

[Ungrounded Lightning Rod]

As I understand it the problem with a small pulley is not the sharpness of the bend but the small amount of contact area.

First, a half-turn has less contact area on a small pulley than a large one.  Circumference is proportional to radius.

Second, when pullies of diverse sizes are coupled, the belt contacts the smaller on on significantly less than 180 degrees of arc, making the patch even smaller.

Force is converved in a v-belt/pulley system.  So the slippage takes place on the smaller pulley.

The smaller radius actually raises the friction per unit area, by the way.  V-belts are so efficient because they enter the pulley straight with little friction, then bend.  The bend causes the sides to bulge and grip the pulley for a positive contact.  When the belt is about to leave it agains straightens, releasing its grab and easily lifting out.  Unfortunately, the increased grab pressure from the tighter turn is more than compensated for by the smaller grab area.  B-(

[hiker]

try this................

[DanOpto]

I suggest considering a timing belt from a car. They are ribbed and don't slip.

The top valve train pulley is twice the size of the pulley off the crankshaft.

If you use the pulleys off an old engine, you can double the generator speed.

A volkswagon timing belt is about $14 canadian. --  Cheap

It takes quite a bit of power and torque to lift the valves at the speed the engine runs.

The belts are good to 6000 rpm and 100,000 miles. They should last a year before needing replacing on a windmill.

[tecker]

  That's a pretty good idea and the wide belt will be less likly to jump off .

 

[tecker]

   What is that ratio 4 to one ?

[tecker]

  With a small belt the contact area is also reduced in 3 or 4 to one combination.

[tecker]

 I got a Minato thing I 've been messing around with made out of cycle parts .

I've been using dry lube ( silicon spray ) .Do use any lube with this setup . I'd be nice to have a a way to lube the chain as it operates  maybe made into a idler and tension at the same time. The dry lube pickup less dirt that motor oil or something like that . I'm also dealing with some metal filings around circuit boards. Like to do something there.

[nothing to lose]

I would use a timing chain and gear set instead of a belt then.

No slippage at all, ever! No adjustments. Should last forever at such low RPM and low stress.

I think last set I bought for a 350 chevy was around $25 and came with the cam/crank gears. Might have cost less even, been awhile since I bought one.

One VERY nice thing about timing chains is that I have never seen one BREAK in normall use. Yes I have replaced MANY broking timing belts (some almost new) but never have I seen a broken timing chain. Well, I have but that was a frozen cam or something on a race engine that busted it, not normal.

 Yes after enough wear they do jump time, but we don't have to worry about that with a genie since we don't care about valves and pistons both being in an exact spot at a certain time. All we care about is that both are turning, no worries about them matching up. So even a well used chain set would be fine for this type app.

I think chains also loose less power than belts, that makes startup easier.