Stator part 2: the WRECKONING!

[Kid Jedi]

Fixing things twice is one of my pet peeves, because it means I wasn't smart enough to solve the problem, i will admit i was 16 when I first attempted fixing the charging system so I give my self a little slack!

Maeve just ate the First replacement stator I have given her. when i installed the second stator I removed ALL of the connectors in the charging system and mounted a large heat sink to the back of the R/R Pictures soon. I run Full synthetic 20-50 castrol because it has a much higher cooling coefficient. I also use water wetter in my cooling system and that keeps the temp a little cooler. 

I got 5k out of the 2nd stator and am NOT doing this sh*t again.

Autopsy shows overheat and independent failure in the 3 windings

I am going to use thermo-conductive paste between the cases and the stator upon reassembly. I am currently researching super hi temp insulator epoxy (650F) If that little b*tch wants to run hot as hell fine, but she aint taking my alternator ever again!

here is he epoxy I am thinking about using
http://www.cotronics.com/vo/cotr/pdf/4703.pdf

Since the windings shorted to the holder I am planning on using Mylar coated cardboard (same used in transformers windings) as an extra insulator around the holder legs

I plan on PERSONALLY rewiring this one. If you want something done right do it your self...

If this works out I might start rewiring peoples stators and offering a lifetime warranty....

[67GTO]

Let H2O know about that lifetime warranty ;)

[inanecathode]

Haha yeah.
Say, jedi, i'm curious how you determined which and how each winding failed after the fact?

[QBS]

The stator wars and intense related discussions have been going on since the first V hit 5000 miles.  I have read and studied all the numerious speculations and theories regarding these chronic failures.  My take on the problem is that it is probably caused by vibration induced insulation failure between the stator coils and their mounting base/holder, aggrivated by non compatable metal contacts in the R/R connector. 

[Kid Jedi]

Haha yeah.
Say, jedi, i'm curious how you determined which and how each winding failed after the fact?

simple autopsy

My take on the problem is that it is probably caused by vibration induced insulation failure between the stator coils and their mounting base/holder, aggravated by non-compatible metal contacts in the R/R connector. 

vibration will be solved by Mylar-cardboard insulators on each arm of the holder, however i do think temp plays a role also, almost every bike form 95' on that doesn't have chronic stator failure has a water pump/ oil cooler Right next to the charging system

[YellowJacket!]

Check your family tree.  You may be related to H2OLawyer.  He eats stators about as quick as you did.  ;-)

David

[kev10104]

You have to like the lifetime warrenty.

[Kid Jedi]

new idea
I think i am going to add a line off of one of the oil passages to the stator to help cool it. Maby drill and tap the crankshaft at the magnet side and install a small jet from a carburetor to drip oil on the whole assembly

[Night Vision]

that idea (or variation) has been tried and pretty much abandoned. drilling the crankshaft bolt was tried, but the experimenter (was it Jeff Swan?) went back to the undrilled bolt.

the Ventures had a patch that was a drilled bolt and slinger....

the better quality stator is proabably a more better idea.

better ingrediants makes better stators 

[inanecathode]

Haha yeah.
Say, jedi, i'm curious how you determined which and how each winding failed after the fact?

simple autopsy

No really, how did you determine which and how. I'm genuinely curious. The entire stator roasts it self to a crisp due to the hard short so im curious how you're able to tell which winding went first. Theres been hundreds of stators gone bad before yours and you're the first to determine which winding went first and exactly where it started to fail.

[Kid Jedi]

ok inane, here is my logic:

When one of the phases on a 3 phase stator go out the other phases have to work harder. more work = more heat. if you look at a cooked stator you will see a pattern, each arm on each phase is equally cooked. ie a blistered arm is always 2 away form another equally blistered arm.  Since a phase shorted to the case does not do any work it is safe to assume that the least cooked arm went first. after dissasembly you can see the discoloration on the copper wires where they started touching each other and the arms

so we know which phase bought the farm first second and last, but what specific length of wire did?

the one thats fused to the holder on the least cooked arm.

Diagnosis:

Stator failure was caused by the enamel insulation of the wires cracking and blistering inside each of the arms.

since failure originates deep inside of the unit temperature must be the cause. an oil cooler would help conciderably, but that voids the oem look, and some people (me) like the look of the vision just the way she is.

Possible solution: overbuild the stator

Advantages are that the stator could take more abuse,  but would eventually fail.

That would be only a band-aid

Another solution: Get oil to cool the stator directly

one could tee off of the oil tube lubricating the rear cylinder, just braze another brass tube to the banjo bolt leading to the stator, using an old carb jet to limit flow

One More: increase the surface contact between the stator and the side case, improving the ability of the case to sink heat away, possibly using a thermaly conductive epoxy that molds the the back of each armature.

I think I might do the last 2, drilling a small oil channel in the epoxy to help oil cool the side case.


Ideas?

[inanecathode]

Well, one of the stator phases doesnt just 'go out' it shorts to ground on the corner of one of the armature arms. When it grounds it shorts the entire stator (Y wound remember) shorts through that ground. What you're picturing in your head is likely a delta wound stator that the rest of planet earth uses in charging systems (better at low rpm high aperage ouput) A grounded circuit with no load on a Y wound stator means all that energy from every winding is converted to heat which roasts the stator in its entirety, from which i dont think one could actually perform an accurate autopsy being that all the insulation on the wire is melted/burned off. Maybe you could find the one wrap that shorted, it'll be the very first wrap on one of the arms, and it'll short right on the corner of the sharp stator core.

If heat was the problem it'd burn itself up within the first ride. The enamel insulation they used on the stator windings isnt a durable insulation. It works good up to a point then catastrophically melts, it doesnt tolerate even one overheating. If heat was the issue all it would take was one overheating and it would be done, and it would be done as theres a little bit of wiggle room down on the stator core and the insulation would run out quicker than you can say clam bake.

The only time delayed failure point beyond the ruled out heat issue would be vibration. The time it takes to wear through a certain amount of insulation would be limited to how long the bike has been running, not how hard or how fast. Every bike having different engine harmonics would explain why some visions eat stators like candy, and some are just dandy. Under no circumstances would i ever concider modifying the oiling system for anything, let alone the valve train, without completely understanding what flow rates and pressures components want to see. If you tap off of stuff and start drilling holes you're introducing leaks into systems that werent designed for it, likewise your pressure would drop. If i were to modify anything at all, i'd tap off of the outlet for the oil pump, before the bypass valve (if the vision even uses it) so the pump has some means to overcome the dropped pressure.

That's just splitting hairs tho really. If you cover the poles properly, use a polyamide coated wire, and dont fuck up and cut the wire when you're winding it (take a dvom lead, attach it to the very end of the spool of wire, and the other to the core, set the dvom to audio and bobs yer uncle) it should last basically indefinitely.

[Rick G]

I question the wisdom of messing with the oil pressure on an engine the occasionally spins the rear rod insert. Not on my engine , I hope to NOT have to install another bottom end! :D

[akvision]

whew! and very interesting. 
I just want it to work and do it's job.
I just bought one from Tim Parrot.  Any history on these rebuilds?

akV

[Rick G]

I think H20 has one , not too many miles on it tho.

[QBS]

In the interest of eliminating a place on the stator frame/base/whatever for the insulation to wear through, what about grinding the sharp angles off where they are insulated from the windings so the windings wouldn't be able to vibrate their way through the insulation so easily?  Would these rounded edges render the finished stator product inoperative or less electically productive?

[h2olawyer]

I went through a stator every 1,000 miles for the past six years.  Just like clockwork.  Even tried a new (OEM) R/R.  One of my problems was that the NEW R/R was bad upon receipt - but I didn't know that at the time & all checks showed OK.  That was one of my issues.  I got another new (Electrosport) R/R and it lasted about 1500 miles before I got charging volts @ 17+.  The new stator replaced at the same time was also up to 1500 miles at that point!   ;D

I went back to the previous (OEM type) R/R.  I did not know for sure if it was 'bad' at this point.  So, deciding to risk it, I rode with the R/R I thought might be the cause of all my headaches. 

I got another 1,000 miles out of the stator before it fried again.  (2500 miles total)   >:(   Ordered another Electrosport type R/R and stator.  That was late last Summer.  I have about 200 miles on that setup so far.  I am considering riding to Kingman, AZ this May, as I do think I can get at least 5,000 miles out of the new system.  I know I can get at least 2500 if the last setup is any indication.  I'll put some test miles on it this Spring before I make the trip, though.

After the past few years, I'd be thrilled to get 5,000 miles out of a stator at this point!  I've tried CPU cooling fan on the R/R, soldering all connections and hooking brown wire directly to positive terminal.  Nothing made any difference - always 1,000 miles per stator.  Only after I got the new R/R did I get longer life from the stator - but then the new R/R died and I confirmed my suspicions that the older R/R was at fault for the extremely short stator life.

H₂O

[inanecathode]

In the interest of eliminating a place on the stator frame/base/whatever for the insulation to wear through, what about grinding the sharp angles off where they are insulated from the windings so the windings wouldn't be able to vibrate their way through the insulation so easily?  Would these rounded edges render the finished stator product inoperative or less electically productive?

It wouldnt hurt, it'd unload the corners a bit and eliminate the sharp corners that just wait to cut through to the wire wrap.

[akvision]

maybe the devil is in the magnet...unbalanced or evil.
magnetism is a bit of mystery.

H2O, I would try a total change out if it happens again.

akV

[akvision]

now I am no engineer.

but I am practical.. follow me on this.

If H2o has a magnet wheel that is unbalanced, like a weak :P and a strong side >:(,  then would this not create an uneven delivery of current and therefore stress the VR  and therefore cause a heat buildup in the VR and the Stator and the ultimate failure of both units??

Like I said, magnetizmmm, it is a mystery.