Stator retrofiting to a different style

[Bart]

It was a good memory when I came to realize that the factory stator output is rated at only 1.5 amps. and everyone has had to deal with it, in their own way, some have sent the stator out to be rewound to 12 volts, and others have attached small alternators, I have been looking at all of these ideas, for the past year,
a while back I was going through some old stators off of some 4wheelers and snowmachines that were laying around, and came across one off of a 2001 Polaris sportsman 500, (4.528")and it was close to the same width as the 084 stator (4.642)" across, and that got me thinking a little bit. the Polaris stator being only .114" narrower, it could work.

The Polaris stator is rated at 250 watts from the factory ( if my calculation is correct that should equal around 20 amps.)
with a spare 084 stator, I took off the mounting plate, to see what it would take to fit it to the Polaris stator. nothing was really looking good, if I milled it flat and to fit, there just was not enough meat left to attach the new stator to it. the only other option I seen was to make my own custom mounting bracket/spacer to attach the stator to the timing gear cover.
So with that thought, I went to visit with my friend who owns a lathe and milling machine, and told him of my dilemma.
with not having a specific design in mind, and trying copy to some extent the original backing plate. we came up with the first design. without modifying the Polaris stator, and it recessed into the bracket as far as I dared. it was sitting still to high.
then we started looking at the casting on the inside of the starter pulley, with the rounded inside corners. it was not letting the stator sit down far enough. so we put it in the lathe and trued it up. you want to be careful with this, it appears to be thick, after trueing it to the base of the stator, the edge thickness is measuring .1530" or 3.88 mm. so making the starter pulley deeper was not a option. but it needed the inside cone, and the outside corner to be squared up for this style of stator.
after putting it on the motor, to see what the fit would be, it was still sitting out almost 3/8" to far.
I was getting a little frustrated, more with the fact, that I had just wasted 6-7 hours of my friends time, sure both of use learned a few new tricks to make the first bracket, to make a bracket from scratch, and to match 2 items together that were not machined to go together, was a fun challenge.
The only option left that i could see was to change up the way the stator mounts to the face plate, instead of using a mounting bracket, all i needed was spacer, to keep everything in alignment.
so the piece of aluminum that was 4"x 4"x 3/4", shrunk down to a round disc 2.5" on the outside, with a 1.67" hole inside, and .5" thick. and ended up with 3 separate sized steps on the outside, to keep things centered.
I ended up attaching the stator directly to the face plate. as you can see the mounting holes on the stator are very close to the seal. not much wiggle room. and with only being able to line up one of the 3 holes, to one of 4 bosses on the face plate, there just is not a lot of meat for the other 2 bolt threads.
so I made up a backing plate so the cap screws would have almost 3/8" or more of thread to hold it in place.

Also I ended up cutting out some of the plastic molding so it would sit down another 1/8 of an inch. Which has brought the original solder joints very close to the face plate.
this was so much simpler than the mounting bracket that was made the day before.
if my measurements are correct, I have a gap of .2640" between the top of the stator and the inside bottom of the starter pulley, more than enough room to solder the 2 wires and not have to worry about any clearance issues.
the height of the 084 stator from the face plate to the top of the stator is 1.4710", and the finished height of the polaris stator is 1.5050" with a height difference of .0340, if I bend over the solder connections that are on top of the Polaris stator, it will lower the overall height to almost 1/8" lower than the stock 084 stator.
things are looking good
I still might look at soldering them back on the bottom of the stator, just would need to see what I will need for clearance so the connection don't short out, on the face plate.
also I need to mill down the 4 existing bosses, where the original stator was mounted, at the moment there is maybe 1/16" of clearance.
For a voltage regulator, I will be using the one that Polaris made for this stator model.
on the starter pulley, we cut off the pull cord ears to start with, and that way we could keep the alignment true. but we found out also that the casting ring where the shaft comes out, is true also. and there was enough there, that the lathe jaws had a solid grip to make the cuts also.

still have a little more to do on this motor before starting it up and seeing if this all works.
but I am having fun trying different approach to the low voltage problem.
please let me know if I might be missing something on this modification.

[Bart]

A couple more pictures of the almost finished project. if this works I will be happy, I know that on the 4wheeler, when the winch is used a lot, the stator has a hard time keeping up. but know I will be able to run with lights and a few small accessories. and if the stator fails down the road, I will be able to change it out fairly simple. I would like to see if I could find a stator with a higher output, but most places don't list the dimensions, of the different stators, and I don't live close to any ATV salvage yards,
hope that this might open up some different avenues for a simple method to get a little more amps out of the charging system.

[Corky]

That's a serious attempt at gaining about 18 more amps !! I'm wondering how much clearance you need between the stator and the engine casing ??? I don't have the answer to that question myself.....But I've seen where some were close and had a non conductive shield behind it to contain the current...The old style was like a thick gasket paper...I'm thinking you could use some type of adhesive backed material between the two if needed...Here's some pics of the factory set-up to refresh everyone's memory...Take note of the sealing/locking material on the shaft that locked the pulley in place..

[Corky]

And I hope the 1.5 amp factory stator charging is a low figure......Heck, I'd do better to just add a small solar panel to the top of my cage if that's all the output will be...

[Bart]

a few questions have came up, and it will be fun to learn some answers for this project.
the space between the coil windings on both the 084 stator and the Polaris coil is from the face plate is around 1/4". I will need to mill the ears down so that there will be the same clearance that I have for the rest of the posts.
I may need to glue some electric resistant cloth or apply some electric resistant coating on the face plate,
I posted a better picture of how much I had to cut away at the plastic molding to get it to a workable height. there are 4 metal rods that you can see. where the wires were solder to. It will be simpler to solder the wires to the top of the stator at the moment
the length of the posts on the 084 stator are .5252 and the length of the Polaris posts are .9025,
I milled out the backing plate to fit the groove on the back side of the face plate.
the biggest question though is on the Polaris flywheel cover, there were 4 magnets glued to the flywheel. or it appears to be one continuous magnet on the newer models. but on the 084 rope pulley, we have 12 separate magnets, along with 12 posts on the stator.
on the Polaris stator, from what I understand, there are 10 posts that feed the charging system. 1 other post with a light brown epoxy on the base, the 2 wires coming off of it went to the ignition coil setup. and then there is one post with no copper wire rapped around it, just the metal field on the end of it like the rest.
at the moment I do not know, how the stator will react to the 12 magnets on the rope pulley?
if someone knows the answer to this question, please speak up.

at the moment, when I get around to installing this set up on my motor, and if it works great, but if it doesn't work, I would be looking at milling out a adaptor to mate the Polaris flywheel to the 084 shaft, at least that is about the only option I see to keep going forward with this idea.

on the Polaris flywheel, the raised part on the outside on the bottom part of the hub is put there for the pick up coil

[bgmcl60]

i never could get the cuyuna 440 i had on my boat to charge enough to run a spot light so i bolted a chevy mini alternator on it to the belt that turned the cooling fan.
i could run 3 100 watt spotlights and still stayed above 13 volts. i used the same setup on my 084. i had to bolt the cuyuna pulley to the front pulley with a 1/8 in plate bolted to the front pulley.

[Bart]

bgmcl60
it would be good to see a picture of how you bolted the alternator to your cuyuna 440, I have a feeling I will be needing to do something like that also with my cuyuna. for I do have a few alternators laying around. and mounting brackets are easy to come up with.
i have been having fun with this little project, at the moment all I have put into this, is my time. but it has made me think and learn a little bit more.
it would have been simpler to just mount external alternator, and i would be done. but after seeing how close of fit the Polaris stator is to the stock stator, it is just something that i wanted to try and see if it was possible. i think i am having too much fun and seem to getting sidetracked way to often on my build.
thanks again.

[bgmcl60]

i don't have any pictures of the cuyuna but i'll try to load some from 084.same setup except the cuyuna was on right side and part of the fan housing was cut out to let longer belt fit on the alternator. i had a switch between the one wire alternator on the cuyuna to turn off the alternator. it did drag the cuyuna down a bit but no effect to 084.

[Bart]

nice set up, you have a lot less time & effort into it, it looks like you had some fun fabing up the bracket that goes on the rope pulley, and the best part it is simple and works.

on the Cuyuna motor where the power band is from 4000 to 5500 RPM's, did you run the same size of pulley? and did you ever notice any more ware in the on the bearings turning the cooling fan, or was there any more belt tension? it never did cross my mind to cut out part of the housing to allow the use of the existing pulleys to turn an external alternator,
thanks for the idea

[bgmcl60]

the pulley is smaller than what is normally used on auto setup and high rpm didn't affect it. it took very little belt tension and never heard the belt slip. once the alternator started charging rpm didn't have much effect on charging rate even at low idle it would charge 13 volts with running lights and a spot light but never went over 14 volts.

[bgmcl60]

i used the 084 front pulley to mark the 1/8 in flat aluminum and l laid the cuyuna pulley in the center of plate and marked and drilled bolt pattern. was dead on first try no wobble at all. this was on the 084. i did use a caliper for measuring.

[Bart]

I did some reading and learned a little more about the magnets that are placed in the rope pulley or flywheels, that they alternate between north or south poles, when they are place around the pulley. checked a few of the flywheels and they all have 12 separate magnets placed in them. on the 4 shoes in the polaris flywheel there are 3 magnets embedded in each shoe.
the simplest way that i found out to know which is the north/south or positive/negative magnet, is to take another magnet and run it around the pulley, it will either attract or repel the magnet in your hand. It doesn't matter which side of the 084 pulley you test it on. i marked the each magnet with a red A having a - negative charge, and a white B for the + positive charge.
i looked around the web, and not knowing the proper verbiage. I found one site that talked about the magnets in generators, stating that the main determining factors for knowing the torque, is the depth of the magnet, the distance of the gap between each magnet, (copied it in the attachments, don't quite understand the math involved)
As you can see in the pictures, you can see from the outline of the magnets that are on the Polaris flywheel. that they are taller, and wider than the ones on the 084 pulley.
i am thinking to find out any more information,as to what amps, this set up will actually send out. i will need to get this installed and fire up the motor. and verify with an amp gauge,

a couple more measurements comparing the differences with this set up.
084 setup
inside of starter rope pulley 4.6560
outside of stator 4.6310
air gap between stator and pulley, 4.6560 - 4.6310= .025, needing to divide this in half for the stator has a gap on both sides. i have .0125 clearance.
air gap between stator and rope pulley .0125

Polaris set up
inside of flywheel 4.5850
outside of stator 4.5252
4.5850 - 4.5252 = .0598 then .0598 * .5 = .0299
air gap between stator and flywheel .0299

final set up
084 rope starter pulley 4.6560
polaris outside of stator 4.5252
4.6560 - 4.5252 = .1308, then .1308 * .5 = .0654
air gap between rope pulley and stator ..0654

GMC 61 amp alternator
inside of windings 4 measurements average 4.1236
outside of rotor 4.0945
4.1236-4.0945= .0291, .0291*.5= .01455
so on this alternator i have a air gap of .01455

i was also remembering back in the day when i would set the point gap on a 5 hp. Briggs and stratton motor, we would always use a playing card, which is .0115
i am not quite remembering what happens to the spark,when the gap is wider. does it get weaker as the gap gets bigger?
really can't remember. i haven't really worked on the ignition on a small motor for almost 30 years.

just thought someone might want to know these measurements. used a Mitutoyo 6" digital caliper for all measurements.

learned something else today, that on the polaris flywheel with the missing magnet, if i come across a single shoe for this flywheel that the embedded magnets are + - +, many have used a very thin coat of JB Weld to glue it back in place, the replacement cost of this model of flywheel is around 400 dollars. i ended up buying a broken down 4-wheeler for 500, and ended up with a few more spare parts.