Is this the final stator solution?

[inanecathode]

I think i've been through a thread like this before...
Not sure but its familiar...

If the stator failure was directly related to heat, it would fail alot faster than they seem to in people's visions, once you surpass the melting point of the insulation just a tiny bit you're done. If its related to the stator shedding heat it would fail after a certain parameter is met regarding current load, ie high rpm for extended periods, yet we all know the vision can handle long interstate periods of high rpm for a long time.

What's common is they fail after a certain amount of time. The dipped insulation being what it is, it won't flow over a period of time in that environment packed in close with other insulated wires and often surrounded by epoxy or some kind of resin. The only time sensitive factors in the stator failing are vibration over time, as it physically removes a tiny layer of insulation every time the part shifts never to place it back, and heat cycles, as the windings expand and contract they grind back and forth over the stator core eventually wearing a hole in the insulation. Once the hole is there the whole kit shorts to ground and creates a stove element and does actually start melting things due to heat.

I do support development of a switching regulator, but i think the most elegant solution would be to rewind the stator with super high temp and strength (polyamide as apposed to cheapo magnet wire enamel), use a protection sleeve of some kind over the stator armature edges and penetrate the outer layer of the stator with epoxy. This way no matter how much it vibrates, and how much heat might be created in the stator due to the shunting regulator, the windings wont move and even if they do, the high strength insulation will hold up much much longer than the enamel type would, and even if there is some possibility of rubbing the protection over the harsh stamped edges of the stator would cushion the movement of the windings on the stator core. You could have the worst built charging system in the world, but as long as your stator is built to high enough standards it will never fail, this is just one big inert coil of wire, not a wear component, it can be made virtually indestructible you know.

The only other thing that could help is to make a cast iron stator core with smooth, even polished, armatures instead of the standard stamped steel sectional construction that is with them right now.

[Rick G]

The one thing that bothers me , is the gradual discolouration of the epoxy , finally ending up as a black charred , bubbled cinder. It appears to me to be heat generated , but internal heat , external heat ?

[QBS]

IMHO, Inane is very correct.  A super well built/quality stator is the answer.

RE Ricks question:  The heat that causes charring comes from internal sources.  The external color change of the insulation results from external heat, the charring does not.  The way that some areas of a failed stator are charred and others are not, indicates that coil shorting to ground is not always uniform, therefore the coils that are shorted are the ones that are charred, leaving other areas of the coil uncharred.  When the entire surface is charred, it indicates that all coils shorted to ground.

In the case of h2o' chronic short lived stators, I would suspect a deeply generated high frequency engine vibration that is unique to his engine.  Think rotating mass, i.e. crankshaft, rotor, connecting rod or rods balance.

[kiwibum]

spoiler alert- Long post.

The only other thing that could help is to make a cast iron stator core with smooth, even polished, armatures instead of the standard stamped steel sectional construction that is with them right now.

Making the polls more rounded  on the stator would help but not cast iron (assuming you mean a solid one) as it needs to be a laminated core. Can't remember the reason for this at the moment however my electrical/electronics training tells me it needs to be laminated such as the design of transformers etc.

Definitely better insulation is required along with high quality of workmanship on materials and construction of the stator is required as I've stated in previous posts on this. "Cycle Electric Inc" mention this in the statement on their HD stators which appear similar to the Vision.  http://cycleelectricinc.com/STATORS.html The problem with this is the additional cost involved, people aren't keen to put a $500 stator into a $600 bike.

Is there anyone that has had stator problems replace the battery, R/R and Stator with new ones at the same time? All three are problematic items and can cause failure of the other items. I've had battery/bike shops say bike batteries should be replace between 2-3 years, and seen many reports of poor battery killing an R/R. I think the problem may be all three items depending on their condition but tending towards the possibility of the R/R causing the stator failures along with poor quality stators to start with. After all the reading I've being doing on this topic after going through all these posts I'm wondering if the problem is actually a poor regulator that takes out the stator but doesn't break down enough to indicate a R/R failure. This appears to be what may have happened to H20.

I think we are all just replacing the faulty part after basic static tests indicate that the others are OK. However a R/R needs to be tested under load and if it's an inherent problem with it breaking down intermittently when hot due to a poor quality component you aren't going to catch it. I don't know what other bikes use the same R/R as the XZ but it would be worth finding out to see if they have any issues.

There is a good description here of how the R/R can affect the stator, I've quoted some of it below.
http://www.zefox.net/~bob/mc/vfr/alternator.html
"There's no doubt that overcurrent damage occurs on charging systems, but the only source of extra current is the battery: A leaky (not shorted, just leaky) positive output rectifier will allow battery current to flow back through the stator windings and then to ground through the negative output rectifiers. The heating effect of reverse leakage on the diode is much greater than that of forward conduction, because of the larger (~13 volts vs .6 V) voltage drop in the reverse direction. Heat tends to increase diode leakage, resulting in thermal runaway. The fractional-ohm DC resistance of the stator windings and harness connections serve to limit the current, often to a value that does not blow the main (30 amp or so) fuse. However, 30 amps through two legs of the stator is more than the windings can take."

I know some of you have moved the R/R to get better airflow for cooling and say this didn't fix the problem. However, how many people when they replaced their stator replaced the R/R with a better aftermarket or OEM device? It's difficult to determine the actual issue when all the variables are only isolated partially.

As mentioned before the XZ isn't the only bike to suffer stator problems as shown here on the VFRdiscussion forum (could be mistaken for ROV other than they appear to have more R/R failures than stators). As you see from the photos in the VFR topic the stator and flywheel are basically the same.
http://www.vfrdiscussion.com/forum/index.php?showtopic=29102&st=60

.... a switching R/R would allow the stator to run cooler in my opinion.
Of course, opening the circuit would cause serious electrical noise....  But no one runs a radio on the Vision, right? :)

A well designed switching regulator would definitely reduce the current flowing in the stator which should lead to increased life.  It might be difficult to adequately control the voltage spikes caused by switching a phase off.  Perhaps with intelligent control unneeded phases could be switched off before they started to provide current.  Or perhaps unneeded phases could be switched off slowly enough that spikes could be controlled.   

I have to agree with Brain and Ken that a switching R/R would be better however this is a much more complex design. Which others are finding in a new design trying to deal with 170VAC spikes when the rectifier is switched from the stator winding. It may have the stator run cooler when everything is working correctly but being more complex may cause more faults in R/R which just creates more stator problems.

What I'm trying to get to here is we need to be a little more scientific hunting down the problem. e.g. recording factual statistical evidence (fault, milage, what else was done/not done) for everyone that has had the problem. Collecting data from all systems such as temps, Volts & current flows. We have oil temp stated as measured at 240F and an indication from "Cycle Electric Inc" that the insulation should cope with up to 425F so is the stator really getting too hot from normal engine running or is it electrical fault conditions that sees it's temp raise too high.

I know these are more questions rather than answers however I see the only answer to the question that has been asked for the last 15-20 years, "what causes XZ stator failures?", being a more pragmatic group approach to collecting relevant data.

And just in case anyone is interest GP bikes use permanent magnet alternators www.mclarenelectronics.com/Products.asp?subtype=b:Permanent%20Magnet&type=Alternators&id=71 although these and there regulators http://www.mclarenelectronics.com/Products.asp?subtype=c:Voltage%20Regulator&type=Alternators&id=72 may cost a little more than a quality(?) OME Vision stator.

[motorcyclezen]

Among other things, I noticed that my wires from the stator to the voltage regulator had melted shortly after I got Emmy running. Previous owners obviously did not access this forum. The discussion I had with Brewski centered around resistance in the wiring--a product of length and gauge. Since I've (had to) shorten the wires and replace connectors, I've noticed that the wiring remains a lot cooler. Fins and oil cooler--I'm for it. But I also think the length of riding we do in an outing would also affect the stator/wiring life; hence, some of the differences in stator lifespan.

Ed--

[Coil Coyle]

The only other thing that could help is to make a cast iron stator core with smooth, even polished, armatures instead of the standard stamped steel sectional construction that is with them right now.

Cathode,
            AC power transmission only became possible after the development of the "standard stamped steel sectional construction" you cite. The major loses of early transformers were in the induced "Eddy Currents" that circulated in the Iron Cores of the first transformers. The stamped steel armature pieces are insulated from each other over a majority of their surface area to confine these errant currents to the thickness of the laminations. In a solid iron core these currents rotate freely 90 degrees to the circuit current and power is lost to the heat that is created in the solid core.

            Note that any welding of the laminations is confined to a single perpindicular bead on a given pole of a stator or transformer. This avoids creating a circuit for eddy currents and the heat that they create.
$0.02
;)
Coil

[h2olawyer]

Is there anyone that has had stator problems replace the battery, R/R and Stator with new ones at the same time? from kiwibum

I replaced the R/R , stator & battery when the original stator fried on my V @ 4500 miles.  It has been since that point that I got 1,000 miles per stator.  That replacement R/R was an OEM type - to which I attached a 12V computer cooling fan.  I replaced the stator & R/R at the beginning of last Summer with Electrosport units.  I got 1500 miles out of the R/R before it quit regulating & was putting 17+ volts through my electrical system.  Switched back to the first replacement OEM type R/R and got an additional 1000 miles out of the stator.

That scenario got me to thinking that my stator failures were likely caused by a faulty replacement R/R in the first place.  Since I had replaced the R/R the first time with a new unit, I didn't figure that could be the problem.  I gave things some thought and figured I was having some odd harmonic vibration that nobody else was experiencing - which still may be the case.  However, after swapping to the Electrosport R/R & getting 1500 miles before it fried, then going back to the first replacement R/R - then getting almost exactly 1000 additional miles on the stator, I am nearly certain the problem was with the replacement OEM type R/R I installed when the first stator fried.

If we can collectively get longer stator life, that would be fantastic - but all I'm looking for is to get at least what y'all are getting out of your stators!  I'm getting tired of replacing mine a couple times a year.  Its the main reason I don't put more miles on my bike.

H₂O

[jasonm.]

H2O, did you connect the brown regulator wire? Most of us know that without that brown wire 17 volts is the result. Lastly to all. Electrosport IMHO sells Chinese junk.  FOr the R/R get a better original item. I know some Honda units are better and used ones form older CB600 sports are common. I can get them cheap from a "wrecker"

[h2olawyer]

Brown wire was connected.  I use the stock connectors still since I am changing parts so often.   ::)   The first Electrosport R/R (the one that died) worked perfectly for a few weeks, then would jump between 14.5 & 17+ volts (spending most of the time @ 14.5).  Finally, it just stayed at the high charge level.  Swapped back to the OEM type R/R and it charged @ 14.5 steadily.  That was when I got the 1000 additional miles out of the stator.  I have a new Electrosport R/R (stator replaced at the same time) on it again.  The last time I rode, it was charging as it should.  I only have maybe 100 miles on it so far & it will be a couple months before I get it back out on the roads again so I can't say I've fixed the problem - but I have high hopes.   ;D

H₂O