Stupid idea or stroke of genius?

[Lucky]

it occured to me today that if i had an electrical part on a vehicle like the stator, but it wasn't hidden inside the engine, like an altenator on a car, that if it burned up i'd know it because i'd smell the burned insulation AND it'd probably be protected with a fuse...

So, electrical wizzards & geniouses, why not connect the stator to the R/R with three big 50A (or whatever rating is needed) blade fuses? or is there such a thing as a "thermal fuse"...i guess that's what a fuse is anyway....

but does that sound like like an area to explore?

--Lucky

[h2olawyer]

Interesting - don't know what the benefit would be other than maybe to save the R/R.  Putting fuses in the stator wires still wouldn't prevent it from frying - they would be downstream from the source of the problem.  Fuse wouldn't blow until after the stator has already failed.  Perhaps someone with more electrical savvy than me can come up with a good reason for installing those fuses.

After frying three of the darned things, my R/Rs have survived fine, though.  I noticed mine was going when the volt gauge started acting funny.  Confirmed it quickly with the Electrosport chart.  Think I actually saw the stator fry (electrically) on the volt gauge.  First, it just dropped from 14V+ down to 13V or lower.  Stayed at that level for a while - 5 minutes or so.  Got it home & started to look at it closely.  After restarting the bike, the voltage satyed just below 13V for about a minute.  Then it bounced wildly between 13V & 15V for about 30 seconds.  After that, the gauge read between 11V & 12V.  First stator, I didn't have the gauge on the bike.  Second one, the voltage just dropped from 13V+ to 10V+.  (until I hooked it through the new power center this winter, the gauge read low)  May have missed the wild bouncing, but I don't think so.

H₂O

[louthepou]

Hum, tough question Lucky. Maybe a bit of both?  ;D

I think that even if the fuses helped, they would only tell you that the problem existed (burning stator) and at that point you'd need to change it anyway. SO, you'd know maybe earlier, or more easily, that the left side cover would need to be removed (again...)

But, since I know next to nothing about these electrons going "weeee!" in the wires (except that when you stick your tongue on a 9v battery it feels weird), I'm sure my analysis makes no sense whatsoever.

Lou

[Walt_M.]

Fusing won't work on the stator as it's a current limited device and the current actually decreases as it fails. Ya'll are overthinking this. The stator problem is heat failure of the insulation. Improve the insulation, improve stator life. Yamaha has already done that with the improved later OEM stator.

[Night Vision]

Walt; is your OEM stator installed? or can you post a pic of your "spare"

[Walt_M.]

It is still waiting for my original to fail or I do my starter clutch and and balancer, whichever comes first. As far as a photo, it looks just like any other OEM and would likely be identifiable only by part number. A savvy Yamaha parts guy could probably help.

[h2olawyer]

The OEM stator I fried first & the used one I just installed had thicker insulation coating than either the Rick's or Electrosport stators had.  They do appear more robust than the aftermarket parts.

H₂O

[Lucky]

Allow me to overthink this a bit..  :)

first, i'm not looking to protect the R/R, i think of this as a stator fix

Your assuming that a stator not plugged in, in a running bike would fry, correct? i'm not sure i agree with that.  just because the magnets induce current, i don't think that equates to current draw. if the current has no where to go, i'm not sure that would make significant heat.

but i believe it's the load on the stator that causes it to heat up & burn the insulation...remove the load (amp draw) the stator doesn't heat up. (other than engine heat) it seems cooling the stator is only needed because of current draw.

for example, an altenator on a car gets hot but rarely fails due to heat.  true it has a cooling fan though..

so, if a device were installed trip a disconnect when an overcurrent occures, this would keep the stator cooler (assuming my thought process is true)

a bad side effect would be the charging system cycling on & off (sounds like an old relay regulator)

fat to chew on...

--Lucky

[Night Vision]

Walt (and anyone else):

I guess I'm more curious about the gauge of the wire in the OEM V stator than the actual thickness of the insulation (I'll get to insulation later).

I have three stators in front of me. One used yamaha OME, one new yamaha OEM (both from various Virago models) and a crispy electrosport.

the electrosport has a thicker gauge wire than the two YOEM's. Their site touts "significantly more output than stock"

uhmmm.... why would we need "significantly more output than stock"?

doesn't that translate to more output that needs to be shunted? if the stock R&R can't handle the additional output, wouldn't that basically be generating more heat within the stator and contributing to it's self distruction?

Insulation: what is it insulating?

insulation works both ways. it can keep cold beers cold and hot dogs hot...

if a stator is "shorting out" because it is overheated, where is the heat coming from? surely the 150 or 200 deg engine oil can't be frying copper wire.

hell, fish don't fry good in a copper bottom fry pan until it gets to 350..

the V stator is (supposedly) "cooled" by oil (hopefully) splashing on it...

what if there was minimum or no insulation on the wire wrappings?
do you think that would more readily let excess heat out / let the oil drippings cool the stator more?

Re: Stupid idea or stroke of genius?
Re:Re: Stupid questions? .... or: what if?

[munkyfistfight]

I like the idea of a Fuse somewhere, but it would basically only work if there was too much juice running through the stator. Has anyone noticed on their Voltage gauges a sudden spike in electricity before a stator blows? If they're overheating from too much juice a fuse would be good to catch it before it happens. If they're overheating because of internal engine temps and inaddequate insulation then I'd say we work on cooling the oil a little better. Of course I'm only stating what everyone else has already said. I just wanted something to talk about!!!  ;) ;D :P

[h2olawyer]

Lucky has already developed an oil cooler.  I'll be installing one on V2 this Spring or Summer.

Just before the latest stator fried, I noticed some wild oscillations from 13V to 15V.  Never went over that point, though.  However, that's measuring voltage after it has run through the R/R.  Also, this one died in a much different fashion than any other I've seen fried.  The Electrosport stator that just died was stamped "Made in China".  Didn't like to see that.

H₂O

[Lucky]

H₂O,
the amount of Voltage your charging system puts out is controlled by the R/R. any voltage higher than 14.7 should be limited by the R/R.

since you had readings of 15v, (and you normally dont) then your R/R isn't doing it's job.  you need to retest it, and consider the possability that the R/R has an intermitant problem (if your tests are still good)...

--Lucky

[Night Vision]

I saw also saw hi/lo oscillations before the electrospew blew...
oscillation was gone after replacement of toasted stator... same R&R

[YellowJacket!]

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

[h2olawyer]

H₂O,
the amount of Voltage your charging system puts out is controlled by the R/R. any voltage higher than 14.7 should be limited by the R/R.

since you had readings of 15v, (and you normally dont) then your R/R isn't doing it's job.  you need to retest it, and consider the possability that the R/R has an intermitant problem (if your tests are still good)...

--Lucky

I was going by the volt gauge, not the multimeter at that point.  14.5V looks close to 15V on that instrument.  It's not extremely accurate.  R/R has been fully & completely tested.  All checks OK.  I may not understand exactly how the R/R does what it does, but I do follow testing instructions well and my eyes aren't too weak to read the digits on my multimeter -- yet.   ;)  It was higher than I'd ever seen it just before it went kerblooie but it may have been 14.7V.  Never seen readings above 14.6 on the multimeter.  Also could have been the 'bounce' in the volt gauge needle.

I am getting a new R/R soon anyway.  Just after the latest stator blew, I touched the side of the R/R.  Couldn't keep my finger on it very long at all - that thing was HOT!  Ran the engine to warm with the multimeter attached earlier today.  Charging stayed very constant at 14.5V ~ + - .03V.  R/R stayed much cooler.  So, R/R is doing what it is supposed to right now. 

Now going to research why the Electrosport R/R is $139 from Electrosport & the same model # is only $99 from Dennis Kirk.  (Electrosport shows $99 on the page with the different models, but click on the right one for the V & the price rises by $40.)  DK lists two different models for the V - one @ $99, the other @ $134.  Want to find out what the differences are.

H₂O

[Mutt]

Here's some interesting reading regarding stator failures. There are different reasons and not every winding is always affected. You have grounded/shorted, overheated ect.

H20, check all your bad stators or what ever you have and see if it's one winding, two or all three bad. Use this website and see if you can compare what's happening to yours. If your failures are consistent you may be able to track it to an unbalanced load or an over load or thermal break down.

http://www.joliet-equipment.com/winding_damage.htm

Mutt  :)

[Mutt]

Going back to the theory of having a balanced load, it seems that putting a fuse on each of the outputs would cause an imbalance should one fuse blow. Too, the current in the other windings would change should a fuse blow on one winding therefore theoretically blowing the other fuses.  :-\

Mutt  :)

[kwells]

could you put a voltometer on each of the 3 wires?

[h2olawyer]

Always been one bad winding.  Both the aftermarket stators shorted to ground.  Beyond the coating around the outer poles of the latest one - which melted, no outward signs of overheating - beyond darkened (but not black or crispy) insulation.  The original Yamaha stator that came with the bike fried the insulation in one area to crispy cinders.

Thanks for the link, Mutt.  Maybe it is a vibration problem???

Better be pretty stout voltmeters.  Not sure exactly how many volts these stators produce, but it is higher than 15V.  Three voltmeters may also cause the voltage imbalance, leading to stator failure as noted in the Joliet Equipment link - unless they are very precision pieces ($$$$).

H₂O

[Coil Coyle]

Lucky,

           Yes.

Fusing won't work on the stator as it's a current limited device and the current actually decreases as it fails. Ya'll are overthinking this. The stator problem is heat failure of the insulation. Improve the insulation, improve stator life. Yamaha has already done that with the improved later OEM stator.

Listen to Walt... 8)

The insulation fails and two conductors on a winding connect electrically. The wire between the points that just connected is now a very short set of coils with very low resistance. Every time the magnets pass that winding the shorted part generates the Electromotive Force that it always did. But now that Voltage is in a circuit with low resistance. Ohms Law says that if you lower the resistance to zero the current goes to infinity. The shorted winding is pulsing high current every time the magnet passes by until finally the burning hot and growing bundle of destroyed insulation finally connects to the iron core and shorts to ground. Notice that your failed stators always have hot bands around the coils that failed, and usually another one or two coils that are just starting to burn.

Or...just listen to Walt  ;)

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.

$0.02
;)
Coil