Stupid idea or stroke of genius?

[kiwibum]

I've been avoiding entering this debate for sometime until I could measure the temp of my stator (I added a thermal couple to connect to a data logger when I rewound mine) but since I'm procrastinating from study I thought I would add my 2 cents :)

My sample only comes from two faulty stators, both had exactly the same problem that one phase was shorted to the core. Pulling off the wire from both units I found an inner coil had fused to or been arcing to the corner of the stator pole, the insulation of the pole was very fragile and worn away where the copper was touching the edge of the stator pole. At some stage when I get time I'm going to post photos on my site of these and how I rewound one.  From what I can tell the failure is due to a few things that together cause a greater problem than individually, that of a break down of the insulation on the polls of the stator core. This is caused by:

• Vibration which exacerbates the situation.
• Tight corners for insulation to stick to and wire to wrap round on stator poles.
• Wire wrapped round in a square rather than a nice circle on the stator poles causing pressure on the corners.
• Heat cycling and two metals with dissimilar heat expansion coefficients. The windings heat up and expand more than the steel core, with the vibration this has them moving slightly on the core, when it cools down the coils shrink faster than the steel core clamping to it. The insulation on the steel particularly on the corners of the core where the wire wraps round takes all this abuse and over time breaks down. This insulation is also expanding/contracting at different rates to the steel core it is on and has oil bathing round it.

If it was a copper wire insulation problem it would be more likely to have shorted turns on the stator (two coils shorted together) rather than wire to stator core shorts. Has anyone had a failure where the turns have shorted?

My other reasoning is anecdotal from the motorcycle shop I get my parts from (they serviced the bike for the previous owner, replacing the stator 3-4 times). When I spoke to them about the stator problem they said it was common for other bikes of that era as well and they made a lot of money out of repairs on them. They would send them out to a couple of different guys that did the rewinding work. The ones they found most successful (lasting longest) were the ones from the guy that powder coated the cores first then rewound them, the ones that didn't last so long were just painted with enamel I think he said.

So here in lies the problem, a complicated design that doesn't really have a cost effective method to repair due to the labor costs to do a really good long lasting job and an economy that makes money out of each failed unit with no incentive to improve it. The guy at the motor rewinding company I bought the wire off to rewind mine said they wouldn't touch work like that due to it being too complex winding process (read has to be done manually) to provide it economically for the customer. It took me two days (I did doodle a bit) to insulate mine and rewind it, at commercial rates you aren't going to pay $400-500 for the time involved in a full corrective over hall.

So we have the problem of replacement stators regularly failing is possibly due to poor stator insulation. Plus this is a very difficult environment for an electro-mechanical device to operate, temperature fluctuations of over 100C (15c-120c), high continuous operating temp (120c?), fluctuating vibrations of 25Hz-166Hz, bathed in chemicals (oil) and unfortunately a complicated stator shape for the pole design which makes a tough place to put an insulating material.

The insulation issue is four fold:

• The stator has to be completely clean for the insulation to properly adhere. Remember this isn't a solid steel block, it's made up of laminations and soaked in oil. The oil isn't the issue for a new stator core BUT it still must be completely free from contamination. I'm wondering if poor quality control and design was the cause of the originals failing.
• The insulation has to adhere to the tight corners of the stator poll.
• Be easy to apply to a complex shape
• find material that will cope with the environment electrically and mechanical
• and for commercial guys something that is quick to apply/cure to be cost effective labor wise.

What is the solution?
My feeling is the insulation needs to be thicker on the stator and the corners of the polls be smoothed out and the only way to get this is do it yourself!  The guys that have used the 3M fiberglass tape are on to something, I would have used this but couldn't find it at the time I did mine. The process I used was to paint the areas of stator to be insulated with POR15 (hard, oil & temp resistant), then wrap the polls with fiberglass using cotton thread wrapped round that to hold it in place and applied resin to the fiberglass. Then hand file the hard resin on each poll to make a nice smooth curve so I had a oval poll to wrap the copper insulated wire rather than a rectangle with 4 tight corners. So I have three layers of insulation, paint, glass and polyester resin and reasonably evenly wound pressure on the copper wire round the polls.

Quite a task, no guarantees but I'm hopping this is the solution. I have a friend looking into what it would take to make a fiberglass mold that would make a two piece section to place on each poll rather than the messy job of in place wrapping. But due to it's small size it's quite a complex item to produce.

I've only done 2000km so far on the rewound one and it will be sometime before it could really be said to last longer than original plus a sample of one isn't statistically significant or proof. But that's my theory on it all and I'm sticking to it for now.

[admin]

You are on the right track.  You could use Tigers light up fuzes  or did you mention those?  Either way one of you guys gets credit.
My though tis though, if the fuses, or one of the fuses blows, that atkes a load off the stator.  But, with no load, will THAT cayse the stator to fry?
It looks like power is not a common denominator.  Extra accessories: stator blows.  No accessories/stock system: stator blows.
What about oil?  Could it be the type of oil we are using?
We should do one post of just burned stator facts.  Who burned their stators and under what conditions.  Type of oil. Type of load. Soldered or plugged.  OEM aftermarket....etc.
We need to look for a pattern and see if we can pin it down to something in particular.
What I don't understand is, these stators are used on other bikes and work.  The RR's are used on other bikes and work.  Why ours??
David

Don't get too far ahead on this Dave, they do fry equally as much on the other brands that use this design. it's not a great setup.  we have been hashing out many different possible solutions to try and extend the life of these for several years now.   I like Lucky's idea of limiting outbound current
maybe a fuse isn't the best way but I think it's the right direction.

-Ron

[Brian Moffet]

And any cheap DVM or VM rated to 100 volts AC would work for monitoring the three phase voltages, this is the only idea here that would give you notice that a few windings were doing the infinite current, zero voltage shorted winding thing.

This may not be true.  Some cheap voltmeters are "tuned" to voltages at 60 Hz, which is not what the Vision will be putting out. 

Brian

[Mutt]

After much thought...and it hurt my brain, I wouldn't limit the current from the load side and limiting the current from the stator isn't feasible either.

The rectifier part of the the R/R is pretty straight foward in the manual diagrams, including the zener. However, the regulator part is a mystery block. The job of the regulator section is to level the voltage within a certain tolerance while shunting over-current to ground and disapating it in the form of heat (dah). By theory when there is a low demand on current (load side) the R/R has to shunt more current to ground. So....after stating the obvious, limiting the load current isn't a problem unless your running way more aux items than you should. I think our problem is in the little IC chip/regulator which is supposed to act as a current limiter via ground shunting.

Any current limiting would have to be done between the rectifier and regulator (see zener in diagram pg 7-10 of the service manual). You can't limit the current between the stator and the rectifier because of the component voltage/current requirements in the rectifier. A current limiting diode circuit might be possible but without knowing the values of the R/R it's a shot in the dark. Also the circuit would require a ground reference. If one of the components shorted it would be disaster!

What are the chances the R/Rs designed for our bikes are not properly matched with the stator and current demands of the bike? A design flaw? No...not on our beloved visions, especially the 82s!  ::)

H20, this is just my humble opinion but I think it's realistic your R/R could be the problem. If there is a tolerance problem with any of the semi-conductors in the R/R, especially the zener, it could affect your stator. The R/R would still test as good (with a regular volt meter).

I'm just wondering what the tolerance is supposed to be on the zeners? I'd love to tear a R/R apart. Just need some sort of mild acid to eat away the epoxy without damaging the components.  :P

Mutt

[Lucky]

I'm just wondering what the tolerance is supposed to be on the zeners? I'd love to tear a R/R apart. Just need some sort of mild acid to eat away the epoxy without damaging the components.  :P
Mutt

Glen's bike had a Electrex R/R in it, & when it was just over a year old it failed & the back MELTED out of it. So, a dead Electrix R/R might be a better candidate to get into than OEM

--Lucky

[Mutt]

If someone has an old bad one send it to me. Even if you have a good new one send it to me! ::)

I'll pay the shipping cost.


I would like to contribute towards a solution to this on going problem. This is one of those long term test deals. The Iraq war could possibly end before we get a solution.

Mutt  :)

[kwells]

The Iraq war could possibly end before we get a solution.

Let's not get crazy here...we all know that won't happen

[Mutt]

The Iraq war could possibly end before we get a solution.

Let's not get crazy here...we all know that won't happen

Funny we should mention this. Nancy Pelosi just got her wishes. House passed a bill introducing funding limitations and the removal of troops by the end of next summer. SOOOOO....we should have a solution to our R/R problems by maybe this winter.  :D

Actually, GW is going to veto it I'm sure, the bill that is, not the stator & R/R solution.

Mutt

[h2olawyer]

Tests on my R/R (and stator) were made with a digital multimeter - NOT a "regular volt gauge".  The volt gauge is merely what alerted me to the problem & I posted what I saw on it before going to the Electrosport test flowchart.  Sorry if that wasn't clear.  Also, the current R/R is an OEM type that was purchased at the same time I bought the Rick's stator 3 years ago.  Tried the one I replaced as well.  Both tested the same & well within all tolerances.

Also, like I have posted several times, I am getting a new R/R just in case something intermittant in the R/R really is the problem.

Coil - On my last 2 fried stators, I have not seen any hot bands around any of the coils.  They both tested at the high end of tolerance on one wire to the other two.  Could be just about to fail in that manner.  The test they both failed is the wire to ground.  I think kiwibum may be on to something.  The windings may short to ground first from vibration & poor stator frame design.  The reason I haven't seen the fried insulation on the last two could be that I saw the problem happen through monitoring the volt gauge on the bike & not put more than a few minutes of time on the stator after that point.  My engine may be experiencing a vibration at just the right frequency to wear the stator frame insulation quickly OR I have just been unlucky & bought two that had poorly insulated stator frames to begin with.

The latest dead stator melted all the insulation from around the ends of each stator winding - out by the flywheel.  All that material then ran down to the bottom of the stator where it re-hardened.  Obviously high heat, but it didn't crispy critter, it melted.

H₂O

[Mutt]

H20, sent you a PM.

Mutt  :)

[h2olawyer]

Got it - All is copacetic!   ;D

Sent one back.

H₂O

[jasonm.]

Walt, when did they improve the OEM stator? Or did you notice this on a recent replacement? I know it is a heat issue. The same design is used on the Venture I have. BUT the early Ventures had the same failure until they installed the "cooling kit". Which became standard after the 1st year. Then stator failures dropped from 1 in 3 within the first 25k miles to 1 in 100 in the first 100k miles.

[Superfly]

Jason,

What was the cooling kit on the Venture?  I have heard of it, but really do not know what it is.

[Night Vision]

the Venture stator cooling kit was "basically" the drilled crank bolt with a wire to keep the orifice flowing.. I'm not sure specifically what other parts were involved... maybe a slinger?..

there has been a lot of back and forth talk on whether this was a good idea for the Vision..

reading Leather's site... Jeff Swan had a drilled crank bolt and then welded it back up? 

BTW I unhibernated SmokeBomb and the low voltage stator tonight.... added the additional ground off the R&R... still charging at 13.8-13.9 at idle...

don't know yet about higher rpms because I can't get there yet... >:(

I still need to sync and tune the carbs because I tore them down again this winter... tomorrow is another day

[Lucky]

NV, at idle, those readings are fine... they should boost up over...2200 or so.

--Lucky

[Night Vision]

yeah, I'm ok with those readings at idle... and it does increase off idle...

my whole point is that I was always at 14.7 at idle with the electrosport stator... even when it was newly installed. it would drop down to 14.5 at 5k rpm....ok per the test chart...

but I still say it was charging hot.....

[munkyfistfight]

Does the Stator put out a constant voltage? As the engine speeds up, does the voltage increase, and is the R/R simply redistributing this energy equally in other directions? I'm curious because I don't understand where your readings are coming from. Are you reading what is coming directly out of the stator?
I'm interested because I'm getting ready to fire up my Junkyard V and want to be ready. I don't want to have to deal with this stator a few months down the road if I couldn't have prevented it in some way.

I have a few more questions: Does wire soaked in oil react differently with current running through it?  Are there other factors like the rotor design, the electrodes outside of the rotor, or how much electricity the stator puts out to how much it gets back?

I know I'm asking alot of questions, but I think more specific questions might help isolate the issue.

[BREWSKI]

Shame you can,t adapt a 12v generator and voltage regulator, and get rid of the problem completely."Old people talk".   Brewski....

[Night Vision]

Does the Stator put out a constant voltage? NO As the engine speeds up, does the voltage increase YES, TO A POINT, and is the R/R simply redistributing this energy equally in other directions? I'm curious because I don't understand where your readings are coming from. Are you reading what is coming directly out of the stator? AT THE BATTERY TERMINALS
I'm interested because I'm getting ready to fire up my Junkyard V and want to be ready. I don't want to have to deal with this stator a few months down the road if I couldn't have prevented it in some way. CHECK YOUR STATOR AT THE THREE WIRE CONNECTION

I have a few more questions: Does wire soaked in oil react differently with current running through it?  Are there other factors like the rotor design, the electrodes outside of the rotor, or how much electricity the stator puts out to how much it gets back?

I know I'm asking alot of questions, but I think more specific questions might help isolate the issue.

this site covers the charging system quite nicely:
http://www.jetav8r.com/Vision/IgnitionFAQ.html

go to this one to test your system:
http://www.ridersofvision.net/Technical/fault_finding.pdf