would you replace a stator with these readings?

[Graham]

Confusion is right. I think I'm going to order a new stator but I'm still going to take the one I've got in to our lab for further testing.

Thanks much.

Good idea.:clap:

 

[Matchless]

Let's see if I'm following this "float". What you're saying is that a stator wire could be grounding out, but when we measure between any two stator leads, we don't notice this cuz we're not measuring between a stator wire and the ground. OK, makes sense. So we can't just rely on a decent ac output test of 60 volts on all 3 stator leads- we have to ohm check the stator to ground.

Not really, because the AC wires are disconnected when doing the AC voltage test the leg to ground can still be measured, but is then going nowhere and the voltage test may seem to be correct. Once you plug in the AC wires then that ground forms a circuit which is common to the ground on the Rectifier/Regulator and the problems starts.

 

[posplayr]

If you get three equal readings (likely to be sin(60)*64= 55 volts) then the short is probably where the three connectors join to make a Y.

.

I'm starting to wonder if some manufacturers are not manufacturing with a grounded neutral got Y wound stators.

As long as the Y is balanced , a grounded neutral would have no effect because it is basically close to ground. The situation becomes unbalanced if each winding is not the same and produces different voltage or during the regulation phases of the R/R.

 

[bakalorz]

I'm starting to wonder if some manufacturers are not manufacturing with a grounded neutral got Y wound stators.

I really doubt it, and would hope not, because they definately wouldn't work

As long as the Y is balanced , a grounded neutral would have no effect because it is basically close to ground. The situation becomes unbalanced if each winding is not the same and produces different voltage or during the regulation phases of the R/R.

The part I made red is absolutely not true. The neutral is exactly as far from ground as it is from positive. (It bounces around near the middle between the two depending on the legs phase relationships at the time, behavior is also slightly different during regulation, but basically still holds)

 

[bakalorz]

I really can't take too much credit for the Phase B (stator tests) and Phase C (R/R tests) parts of the stator pages. I only modified the Phase A. However, we have had a few instances in the last couple of years where people have run into stator issues where they try to apply the stator tests and they get confusing of false results and end up wasting a bunch of time. I think it was Psyguy who had a temperature dependent stator problem he wrestled with for quite a a while before he finally just changed the stator and got over it.

So while there are so die hards (who will want to use an ohm meter even though it really is a not a good choice), it may be that the best test solution for a stator is really to just :

a.) test the R/R instead (to rule it out)

or

b.) replace the R/R with a know good (also to rule it out)

and go back to the start of the stator pages and if the problem persists change the stator.


The reality for stator is as I posted before most of the stator tests are circumstantial. Few of the tests are conclusive if all you have is a AC volt meter and a ohm meter.

When I have time I'll try and look at rewriting the other phase to reflect these realities. Swapping parts can be just as effective as testing for a defective unit and in the case of the stator actually much better to just swap parts.

I'll disagree with a lot of this.

A philosophy of just randomly swapping parts trying to "get it fixed" is a pretty poor way of trying to repair things in general.
Much better to actually diagnose what is wrong and then fix that

In particular for the electrical system on GS's there are a couple of problems with just swapping stuff:
1) the parts are relatively expensive (especially compared to the value of the whole bike) to where a couple of swaps cost more than the whole bike is worth even if you get it running perfectly. (do you really expect the average GSer to spend $300 in parts to possibly get a $500 bike running right (with no guarantee that it even will after that))
2) A lot of our problems tend to be degraded connections somewhere.
Swapping everything out wont cure any of that, unless you get lucky and fix the connection during the swap (in which case you wasted a lot of money)

Regarding the stator testing specifically; while no test can tell you that you have a good stator, the various tests can definately find bad ones.

The 60 volt AC test will definately find some stators that are defective
(probably turn to turn shorts inside.)

The ohm test WILL find any that have an open (either internally or in the connections to-from) (BTW, given the difficulty accurately measuring the phases with the average multimeter, the criteria could well be changed to: less than (say) 10 ohms and the three phases should be roughly equal (within say 20-30 percent) (of all the tests, this one could possibly be dropped ... but even then, its easy enough to do, and can rule a stator as bad)

And finally, the resistance to ground will find any (such as in this very case being discussed here) which are shorted to ground. Which definately MUST be repaired or replaced. (and FWIW, a resistance to ground measurement is ALWAYS, ALWAYS, ALWAYS part of the testing for generators and motors in the real world in industry, dropping it from the stator papers would be ludicrous and irresponsible)

---

Are there stators that will pass all these tests, but still be defective (like Psyguys) and the only way to find it is swapping ... sure, it can and does happen.

So sometimes you get through the chart and nothing makes sense, and the only way to fix it is to start swapping parts randomly till you hopefully fix the problem ...

... but leave that as the absolute last resort when you've tried everything and can't find anything, not the _default_ because its too complicated to actually troubleshoot.

 

[Guest]

Hmmm well...

Hmmm well...

After just reading the last comments, my conclusion is just sorry ass design to begin with. The Japanese manufactures just didn't put in the effort and research in to have a decent charging system. If they have built the electrical/charging system like they did the engines, we wouldn't need this forum to begin with.

 

[posplayr]

I really doubt it, and would hope not, because they definately wouldn't work

If it is balanced you can not tell the difference. if the neutral is grounded or not there is no current flow.

The part I made red is absolutely not true.

If you review 3 phase Y configuration.

http://www.allaboutcircuits.com/vol_2/chpt_10/5.html

or simple looks at the phasor diagram for a balanced Y, neutral is zero volts same as ground is.

 

[posplayr]

I'll disagree with a lot of this.

.

Sorry but you ran off on a tangent again.

A philosophy of just randomly swapping parts trying to "get it fixed" is a pretty poor way of trying to repair things in general.
Much better to actually diagnose what is wrong and then fix that

.

I did not say to randomly start changing parts. You either did not even read my post, or don't grasp the concept I was trying to convey.

Just so you know, I have been working in the area of Diagnostics and Prognostics and for US Army ground vehicles for the last couple of years. Part of that is the development/improvement of "efficient" maintenance activities to optimize logistic metrics like Ao and Mean Down Time (MDT).

In one of the internal company presentations I did last spring I described methodologies for improving vehicle fault isolation. Fault isolation is what the stator pages is about.

What all that means is I can prove mathematically my suggestion is more time efficient than the current stator pages diagnostic method. The primary reasons for this I already stated in the previous post.

 

[tom203]

After just reading the last comments, my conclusion is just sorry ass design to begin with. The Japanese manufactures just didn't put in the effort and research in to have a decent charging system. If they have built the electrical/charging system like they did the engines, we wouldn't need this forum to begin with.

Do you believe that they would all ( Suzuki, Kawasaki, Yamaha, Honda ) make millions of crappy charging systems and hope no one would notice. They all experimented with different approaches, but the typical system seem to wind up as what we find on early 80's suzukis- a revolving rotor/flywheel and a stationary 3 phase stator with 18 poles. My son's 07 ninja uses this exact system. Are there better approaches? sure, how about a car type alternator where the field can be controlled precisely. This was tried and used on 70's suzukis and yamahas, but most likely had its own problems- some bikes today use this system.
Some folks here are still using 30 yearold stators- I just replaced mine (1981) two months ago.

 

[posplayr]

After just reading the last comments, my conclusion is just sorry ass design to begin with. The Japanese manufactures just didn't put in the effort and research in to have a decent charging system. If they have built the electrical/charging system like they did the engines, we wouldn't need this forum to begin with.

I agree, the PM stator charging system with SHUNT control is crude and failure prone under the normal anticipated operation of these bikes. The alternator is a primary alternative but is apparently too expensive for most production bikes. With the SERIES R/R you can get the best solution (although not best in terms of cost).

If you are feeling ****y about a 25 year old charging system burning up, go look at what Aprilla guys have been dealing with..............

http://www.apriliaforum.com/forums/showthread.php?t=160360

 

[tom203]

If it is balanced you can not tell the difference. if the neutral is grounded or not there is no current flow

Yes, but this brings up the old headlight switch . Pre 1982 bikes could block one leg of the stator, definitely causing an unbalanced load.And what about the compufire- does it limit current in all 3 legs or just one?
I think some of these recent charging post problems are not typical- your stator tests would probably be conclusive for most stator/ rr problems. There's always aberrations to make life interesting.

 

[posplayr]

Yes, but this brings up the old headlight switch . Pre 1982 bikes could block one leg of the stator, definitely causing an unbalanced load.And what about the compufire- does it limit current in all 3 legs or just one?
I think some of these recent charging post problems are not typical- your stator tests would probably be conclusive for most stator/ rr problems. There's always aberrations to make life interesting.

Yes you are correct. There are several things that cause the load to be unbalanced. I remember actually hearing the difference in the way my GS750 idled when a stator wire was going through the headlamp switch.

I'm not suggesting grounding the neutral is a good idea, simple that maybe some of these stators are coming from the after market that way.

I shop owner on the Aprilla website had installed 2-3 Rick's stators each of which was shorted on installation. Kinda hard to explain 3 defective ones in a row or poor installations?

UPDATE: There may have been an update, looks like he was running into a poorly fitting stator

http://www.apriliaforum.com/forums/showpost.php?p=2617610&postcount=334

I assume the Compu-fire limits current in all three legs, but I did not measure it.

 

[tkent02]

As crappy as these charging systems are, I have still never had one fail, after a lot of years and miles on something like 20 Suzuki GSes. I clean all the electrical connections when I buy each bike before riding it, test the system, then run the Bejeesus out of all of them, nothing has failed yet. I have had several with charging problems when I got them, every one had corrosion in the wiring which caused the failures. Replace a burnt part, clean all the connections, no troubles after that, ever.

If they had junk engines that wore out after ten years, likely no one would even know the charging systems suck.

 

[Graham]

One of the reasons the stators fail is oil or more of what’s in the oil. Additives and detergents can (over time) degrade the thin insulation on the coil wiring. Then just add the fact that the regulator sends full current back to (shorts) the stator coils via a thyristor (in the regulator) to prevent over charging.
Street bikes are made to run mid RPM most of the time not full. Full RPM will max out the current load on the stator.
A GS stator has a hard life and does a good job for a 25+ year “crappy charging system”.

On a side note; I’ve been working on motorcycles since the late early 80s and I never heard of an unbalanced charging system. Is this a new term? The bridge rectifier (in the regulator) will balance stator current and the zener diode (in the regulator) controls voltage. The loads are never balanced, that’s why there are different size fuses. What is unbalanced?

 

[posplayr]

One of the reasons the stators fail is oil or more of what’s in the oil. Additives and detergents can (over time) degrade the thin insulation on the coil wiring. Then just add the fact that the regulator sends full current back to (shorts) the stator coils via a thyristor (in the regulator) to prevent over charging.
Street bikes are made to run mid RPM most of the time not full. Full RPM will max out the current load on the stator.
A GS stator has a hard life and does a good job for a 25+ year “crappy charging system”.

On a side note; I’ve been working on motorcycles since the late early 80s and I never heard of an unbalanced charging system. Is this a new term? The bridge rectifier (in the regulator) will balance stator current and the zener diode (in the regulator) controls voltage. The loads are never balanced, that’s why there are different size fuses. What is unbalanced?

In Electrical Engineering analysis of 3 phase power, "Balanced" refers to all three phases from the stator being of equal amplitude and each 120 degrees out of phase with each other. In that condition the neutral of the Wye configuration is zero volts with respect to ground because all three phases (when balanced) sum to zero.

Things that make the three phase unbalanced, are among other things:

• imperfect winding that make the voltages slightly different in voltage or phase
• shorted winding that make the winding less equal
• regulation causes imbalance because you no longer have sine wave symmetry when the R/R SHUNT a leg.
• Running one of the stator legs to the head lamp switch.

In house wiring, there is a neutral and a ground. The ground is literally that , a piece of copper wire running into the ground. The neutral is actually this balancing point in the 3 phase power. Neutral and ground can be close but they due to imperfections they are not the same.

BTW most of the SHUNT R/R use an SCR, that is fired by the zener control. The new FET type are more digitally controlled as the SERIES R/R's are as well. The Electric Bike SERIES implementation also uses SCR's


As far as oil breaking down the insulation, well maybe if the stator were able to last that long. My Electrosport got brown in 250 miles. So chemical breakdown of the insulation, was not a factor. Running low on oil certainly is though as the reduction in cooling does play in big part in the stator longevity.

 

[bakalorz]

OMG !!!

Really ???

You really thought ANY of the below was right ???

I was actually shocked you understand the stator so poorly to write what you did ...

Every time I argue with you, it's like seeing a living breathing example of the Dunning?Kruger effect.
It's very frustrating trying to explain things to you: You know some stuff, but when you are out of your depth, you just don't even have a clue what you don't understand, or why, and you keep pushing the same wrong ideas and just won't let it drop.

And it drives me nuts, because you keep pushing the half truths and leading the other troubleshooters astray.

I almost can't believe that after all this time, you still don't get how the stator system interacts with the R/R at such a simple basic level (not knowing the relationship between system ground and the neutral of the stator)

And don't try to pretend its just a detail, it's the entire point of why there isn't a grounded neutral.

If it is balanced you can not tell the difference. if the neutral is grounded or not there is no current flow.

If ground were connected to NEUTRAL or disconnected there would be no current flow (in house wiring and AC distribution this is commonly true)
But thats not how it's connected.

In the case of a motorcycle stator system, ground is connected to the lowest phase at the time through one of the bottom diodes. This lowest phase is about .6 to 1 volt below ground.
V+ (12 V) is connected to the highest phase at the time through one of the top diodes. The highest phase is about .6 to 1 volts above V+


Depending on the exact phase relation at the time, the neutral connection of the stator will be somewhere between 1/3 and 2/3 of the way between them (i.e. 4 to 8 volts, averaging 6 volts)
But it is definately absolutely positively NOT GROUND.


THIS IS WHY YOU CANNOT (ABSOLUTELY CANNOT) USE A GROUNDED NEUTRAL WIRE.

and the OEMs are definately not making them with grounded neutrals.

PERIOD, end of story, stop flogging the dead horse of a grounded neutral.

If you review 3 phase Y configuration.

http://www.allaboutcircuits.com/vol_2/chpt_10/5.html

or simple looks at the phasor diagram for a balanced Y, neutral is zero volts same as ground is.

Thats a nice picture and explanation, unfortunately you don't seem to understand what parts of it apply and what parts don't.


Note that nowhere in that does he even MENTION ground.
Because ground can be connected to neutral, OR IT MIGHT NOT BE.

Guess which case a stator system is ....

 

[bakalorz]

I did not say to randomly start changing parts. You either did not even read my post, or don't grasp the concept I was trying to convey.
.

tell me what parts of the following I "didn't grasp the concept" of
(its a direct quote from you)

So while there are so die hards (who will want to use an ohm meter even though it really is a not a good choice), it may be that the best test solution for a stator is really to just :

a.) test the R/R instead (to rule it out)

or

b.) replace the R/R with a know good (also to rule it out)

and go back to the start of the stator pages and if the problem persists change the stator.


The reality for stator is as I posted before most of the stator tests are circumstantial. Few of the tests are conclusive if all you have is a AC volt meter and a ohm meter.
(MRB comment: Most of my post was explaining why the tests _ARE_ conclusive if interpreted correctly)

When I have time I'll try and look at rewriting the other phase to reflect these realities. Swapping parts can be just as effective as testing for a defective unit and in the case of the stator actually much better to just swap parts.
​

My point is that rather than removing (useful) tests, a better way to improve the stator pages would be to better explain the tests that are there.

​

And now that I think about it, you should actually add some tests (and yes, they are just using a voltmeter and an ohm-meter)
What should be added is to repeat the tests already there
(65 VAC test, phase-phase resistance test, phase-ground resistance test) but under conditions which may be causing problems.
In particular, Hot (i.e after riding for 10-20 minutes), maybe wet (spray stator area with hose mist), High revs (to catch stator insulation breakdown as the stator output voltage rises)

A stator that passes all that is EXTREMELY unlikely to be the cause of a charging problem.
(Psyguys would have failed hot and pinpointed his problem, for example)

What all that means is I can prove mathematically my suggestion is more time efficient than the current stator pages diagnostic method. The primary reasons for this I already stated in the previous post.

HA HA HA HA HA !!!! ... I REALLY don't believe this part, I'd like to see this mathematical proof.

Don't forget to account for the significantly greater time to actually remove the stator than to disconnect three connections and measure some voltages.
Does the oil have to be drained, (or the bike supported in some special way to alleviate this)
Don't you have to remove the starter to get to the wires.
I seem to remember lots of people having problems getting the stator cover off ...

And you're trying to say this is easier than doing some tests with a VOM ...

HA HA HA HA HA !!!

And we won't even consider the much greater cost of swapping.

 

[posplayr]

OMG !!!

Really ???

You really thought ANY of the below was right ???

I was actually shocked you understand the stator so poorly to write what you did ...

Every time I argue with you, it's like seeing a living breathing example of the Dunning?Kruger effect.
It's very frustrating trying to explain things to you: You know some stuff, but when you are out of your depth, you just don't even have a clue what you don't understand, or why, and you keep pushing the same wrong ideas and just won't let it drop.

And it drives me nuts, because you keep pushing the half truths and leading the other troubleshooters astray.

I almost can't believe that after all this time, you still don't get how the stator system interacts with the R/R at such a simple basic level (not knowing the relationship between system ground and the neutral of the stator)

And don't try to pretend its just a detail, it's the entire point of why there isn't a grounded neutral.



If ground were connected to NEUTRAL or disconnected there would be no current flow (in house wiring and AC distribution this is commonly true)
But thats not how it's connected.

In the case of a motorcycle stator system, ground is connected to the lowest phase at the time through one of the bottom diodes. This lowest phase is about .6 to 1 volt below ground.
V+ (12 V) is connected to the highest phase at the time through one of the top diodes. The highest phase is about .6 to 1 volts above V+


Depending on the exact phase relation at the time, the neutral connection of the stator will be somewhere between 1/3 and 2/3 of the way between them (i.e. 4 to 8 volts, averaging 6 volts)
But it is definitely absolutely positively NOT GROUND.


THIS IS WHY YOU CANNOT (ABSOLUTELY CANNOT) USE A GROUNDED NEUTRAL WIRE.

and the OEMs are definately not making them with grounded neutrals.

PERIOD, end of story, stop flogging the dead horse of a grounded neutral.



Thats a nice picture and explanation, unfortunately you don't seem to understand what parts of it apply and what parts don't.


Note that nowhere in that does he even MENTION ground.
Because ground can be connected to neutral, OR IT MIGHT NOT BE.

Guess which case a stator system is ....

bakalorz,
I raised the ground neutral as a possibility to explain all of the shorted stators. No I did not think this was an OE design, but rather a possibility from some after market suppliers.

Thanks for your explanation, however, it can be simplified much further. Looking at the individual winding if neutral and ground were connected each would be shorted through a diode which would render the stator inoperable for at least 1/2 a phase.

So we can therefore conclude that all of these shorted (to ground ) stators are either damaged, improperly installed or have manufacturing defects.

This only increases the argument that the stator pages should avoid doing open circuit stator tests.

As far "Dunning?Kruger effect", thats pretty funny . The fact that I explored the possibility of a shorted ground is certainly not sufficient to draw that conclusion. Look whose jumping to erroneous conclusions; certainly none for me???

You are just slinging mud now, but then again that has been your style since I have known of you. I had hoped that you might have matured a little ; you have had an additional two year to do that.

 

[Guest]

Still...

Still...

Do you believe that they would all ( Suzuki, Kawasaki, Yamaha, Honda ) make millions of crappy charging systems and hope no one would notice. They all experimented with different approaches, but the typical system seem to wind up as what we find on early 80's suzukis- a revolving rotor/flywheel and a stationary 3 phase stator with 18 poles. My son's 07 ninja uses this exact system. Are there better approaches? sure, how about a car type alternator where the field can be controlled precisely. This was tried and used on 70's suzukis and yamahas, but most likely had its own problems- some bikes today use this system.
Some folks here are still using 30 yearold stators- I just replaced mine (1981) two months ago.

I suppose I should have been more specific then. The early 80's GS's had crappy charging systems. The evidence is this forum over the years. I know that I have bad luck on my bike (GS750ET) when it comes to stators and RR units and know a many others as well. It was a **** design. Though I'm sure the other manufactures had their share of crappy designs as well.

 

[tkent02]

Dammit! Running out of popcorn!