starter generators... Why are ring gears used?

barnyardorange · Apr 1, 2019

So my original post below about converting my case cc to some type of assisted starting has me wondering if I can find a starter generator powerful enough to start 30 ish horsepower. I suppose to answer my own question the ring gear to a gear reduced starter would be the reason why starter generators aren't efficiant enough. But would a starter generator work for what I am trying to do?

rustred · Apr 1, 2019

the cub lowboy has the generator starter. I don't think it would be strong enough to turn that engine over. whats wrong with the original starter?

barnyardorange · Apr 1, 2019

It is family history and the tractor wasn't built from the factory with a starter.

Janicholson · Apr 1, 2019

Richard G below in the original post is really on target. The starter ring gear is near hidden, and allows the belt pulley to function. Select your junk yard starter and matching ring gear from an automatic trans car. Have a machine shop fab a ring that fits just inside the rear flange of the pulley and extends outward an inch. have them center the ring gear and flex plate and weld them together then have them plasma cut out the center of the flex plate. Install the formed ring inside the back of the pulley and drill and tap for about 5 1/4 28 flat head machine screws countersunk into the pulley and threaded into the formed ring. Make up a sturdy mount for the starter motor that is bolted to the tractor, not welded. Position the starter so it does not interfeer with the belt access or operation. Jim

Janicholson · Apr 1, 2019

RIng gears are used to place a 10 to one ratio or more between the starter motor pinion, and the engine. The reduction style starters also increase the ratio. this allows the armature of the motor to turn faster, and make more Torque with less amp draw. Jim

used red MN · Apr 1, 2019

I think the only way that would come close to working is if you could make the starter spin up a large flywheel like on a square baler. Then that would drive a gear reduction connecting to a throw in clutch that would give you a couple turns on each spin up. Might as well figure out how to mount a normal starter as others suggested.

Texasmark1 · Apr 2, 2019

Not an expert here but listening to starters back in the 60-80 time line I recall that Chrysler products had starters that made a funny noise. Was told it was due to the reduction gear. Nowadays I'm finding them in other vehicles with small wires for power. May be lighter weight, or less copper with it's current price....

Russ from MN · Apr 2, 2019

I saw an old Farmall that a shade tree engineer had put electric start on, he did very nice work. It was an F 12/ F20, and he had mounted a flex-plate in the jack-shaft area between the clutch and the transmission. So it was like a motorcycle, clutch out, transmission in neutral to start, worked well!

buickanddeere · Apr 2, 2019

(quoted from post at 21:59:30 04/01/19) RIng gears are used to place a 10 to one ratio or more between the starter motor pinion, and the engine. The reduction style starters also increase the ratio. this allows the armature of the motor to turn faster, and make more Torque with less amp draw. Jim

More torque at the loss of cranking rpm .
If the starter has PM, it will have higher efficiency than a starter with an energized field .

Bob M · Apr 2, 2019

Starter-generators by design are a compromise. For the same physical size (and cost) they offer less starting torque as a traditional starter, and lower output/efficiency than a generator. They also require frequent maintenance to keep them working.

My experience with them (on first generation garden tractors with Kohler and Wisconsin engines) is a starter generator works OK if everything is perfect (fully charged battery, properly tensioned belt, healthy engine with a working compression release, etc). However if anything is NOT perfect - tired engine, worn or wet drive belt, etc - starting becomes difficult. This's why starter generators have disappeared, with ring gear starters and flywheel alternators now the norm.

Crazy Horse · Apr 2, 2019

Barny ..... I meant to ask this yesterday. The tractor as-is must be a brute to start if you are going to all this trouble for an electric start. Can you start it at all with the hand crank?

barnyardorange · Apr 2, 2019

Crazyhorse: I had it kickback a few years ago and it scared me enough that I figured I need a better idea for starting it. If the crank hadle wasn't so long it wouldn't bother me as much. My allis wd and allis b, both have started fine with the crank and never scared me, as the cranks aren't overly long like the case is.

BarnyardEngineering · Apr 2, 2019

Ring gears are used because you can get a much better multiplication of force. The starter pinion gear can be very tiny while the ring gear is very large. Reductions of 12:1 or more are easy. With a pulley you can only go so small on the motor, and only so large on the crankshaft, limiting you to 4:1 or 5:1.

Ring gear starters aren't used as generators because when the engine is running, that gear reduction turns into a gear multiplication. When the engine is turning 1500RPM, the starter is doing about WARP 4. That'll last about 2.7 minutes without constant lubrication, which makes the whole thing way more complex than it really needs to be.

There isn't a starter-generator off the shelf that would turn over a 30HP engine without the crankshaft pulley being over 3' in diameter.

chcase · Apr 2, 2019

It wouldn't hurt to recheck your timing of your mag.I own a few c and cc,s and a ch case.If the timing is off or you don't have the mag fully retarded, It can be dangerous to hand crank.As I have gotten older you need to become more fussy on those details.They only built the last 39 case cc,s with starters.I have seen a few ring gears put on the belt pulleys.None very nice looking.

starter generators... Why are ring gears used?

barnyardorange

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rustred

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Janicholson

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used red MN

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