Super stator !!!

[Larry D]

Hello All, I've been trying to sort out a weird charging issue on my '84 GS1100GK with the help of bwringer. Let me preface this post with the fact that I know next to nothing about electrical things. Amps, volts, wattage.....I should've paid more attention in science class I guess. But, with the help of bwringer we (he) figured it out last night.

After the initial test a few days ago, of the R/R, it would charge well past the desired range, we stopped testing when it reached 17 vdc....so, that one is fried. We also decided that cleaning up and using some new spade connectors was in order. I got to work on that and got it all done and pretty. I also took the ignition switch apart and cleaned it up too.

Mr bwringer was also nice enough to let me "borrow" his spare R/R off of his GS850, that he had replaced with a Honda unit. This R/R is known good and he carries it as a spare. He also has a R/R from a late model Honda, a VFR 700 IIRC, that he left with me as well. The one from his 850 bolts right up to the stock location on the GK and was an easy install.

So, everything installed, cleaned and replaced connectors, ready to go !!!

NOT.

All the numbers from the Stator papers were checking out, albeit a little on the high side. What was concerning us, was the 850 R/R was getting hot, hot , hot within about 60 seconds of starting the bike. Hot, as in in too hot to touch. Something is not right......

When *I* tested the vac from the 3 stator legs, the Stator papers say that over 75 vac @ 5000 rpms is good.......it was over 75 vac so, I thought it was good. I had no idea how good is good.
After the cleaning and rewiring, Brian tested the 3 legs of the stator and @ 5000 rpm it is making....are you ready ?.......

103 VAC !!!!!!!!!!!! It's a Superman stator from the planet Krypton !!!!!!

The poor little R/R from the 850 was doing it's job as best it could and was getting so hot, so quickly from it's efforts to shunt the extra voltage. We knew it was an aftermarket stator from the leads, but had no idea it wasn't "stock"

After replacing the 850 R/R with the one from the Honda VFR700 which is a higher capacity R/R, the charging system performs perfectly and locks in at a nice 14.3 vdc without the R/R getting hot at all. The only downfall is the Honda R/R is about the size of a refrigerator but, I'll find a place for it. Hope my ramblings make some sense.

A HUGE Thanks to bwringer for his help.

[Nessism]

Hi Larry,

Glad you figured it out. Got a chukle out of your comment about the "late model" VFR700 since that bike came out in 1987.

[Larry D]

Hi Larry,

Glad you figured it out. Got a chukle out of your comment about the "late model" VFR700 since that bike came out in 1987.

Well.....it's later than '84.

Have you ever heard of a stator putting out +-100 vac ? It should be something around 75-80 vac......right ?

What advantages, if any, does this give me ?

[Nessism]

Output voltage is related to the diameter of the wire used in the stator and the number of turns. Thinner wire, but more turns (compared to stock) gives higher voltage (I think). Alternate to this is thicker wire, but less turns, gives more current (I think). I know just enough about this stuff to be dangerous...either Steve of Pos (Jim) should be along shortly to properly answer this question

[bwringer]

I'm not sure what model that Honda R/R came from -- it's sort of a weird trapezoidal shape because it was a visible styling element on that bike. But it's one of the higher-capacity models because it has two ground wires and two positive wires (plus a sense wire).


It is correct that thinner wire = more turns = higher voltage but somewhat lessened current capacity, and that thicker wire = fewer turns = lower voltage but more current capacity, or at least more resistance to overheating and such. There's a balance you need to achieve somewhere in there. The stator leads were all yellow, and covered with a cloth-like insulation. Didn't know if anyone recognized this.


A nice side effect of this process of elimination is that Larry spent a good bit of time going through the wiring harness, cleaning connections, fixing various problems, and cleaning the ignition switch, and now has very little voltage drop anywhere -- less than .2 volt. It can be done, folks...

[Steve]

What advantages, if any, does this give me ?

...either Steve of Pos (Jim) should be along shortly to properly answer this question

OK, OK, I heard my bell ringing.

Nessism was real close there, the voltage output is directly related to the number of turns around the stator poles. The diameter of the wire will affect how many turns you can get on there, but it does not directly affect how much voltage is produced.

There are a couple of other factors that affect how much voltage is produced. One is magnet strength. Unless you damage your rotor, there is not much we can do about that. The other factor is speed. The voltage is produced by alternating a magnetic field across the copper windings around an iron core. The faster you alternate the magnetic field, the more voltage you will see. If you use smaller wire, you will have more windings and will produce more more voltage sooner. If you use larger wire, it will carry more current to power more "stuff", but there may not be enough turns on there to produce enough voltage until the engine is spinning a bit faster than idle. Yes, it's a delicate compromise.

The newer-generation FET rectifier/regulators help a bit at both ends of the charging curve. They have lower switching losses at the bottom end, so they pass more voltage sooner, which might compensate a bit for larger wire (fewer turns). Because of these lower switching losses, they are more quicker to switch from 'full ON' to 'full OFF' in the regulation phase. This means they will tend to run cooler, and more of what you are generating is available for use, not being wasted in heat in the r/r.

Posplayr can put his engineering spin on this, too, but this will probably explain it to most.

.

[Larry D]

I'll take some pics of the Honda R/R tonight to see if anyone can identify it. Frankly, it doesn't matter to me what it is, all I know is it performs well. The guys over at the shop where I work is making me a nice mounting bracket today. I'm certain if I hang it vertically it should fit just fine behind the side cover, near the original postion. I'll snap some pics of my progress on that this evening too.

So, will I be able to run a coffee maker and the wife's hair dryer ??

Thanks Guys.

EDIT:: Going back and reading about voltage at idle......what is the "normal" voltage at idle ? Mine was +-32 volts, IIRC.

[posplayr]

I think Steve covered most of it. From reading the thread, I would have two concerns:

1.) I would have my VOM checked or investigate operator error (is it on the right scale ); 100V RMS from the stator might be believable, but 32V DC at idle is very suspicious.

2.) After cleaning your connections to the R/R the temp should have dropped. When the R/R is getting hot first thing to check are the Red/Black DC out connections. If the R/R can't pass the power to the system, it has to short it back to the stator and they both get hot.

[Larry D]

I think Steve covered most of it. From reading the thread, I would have two concerns:

1.) I would have my VOM checked or investigate operator error (is it on the right scale ); 100V RMS from the stator might be believable, but 32V DC at idle is very suspicious.

2.) After cleaning your connections to the R/R the temp should have dropped. When the R/R is getting hot first thing to check are the Red/Black DC out connections. If the R/R can't pass the power to the system, it has to short it back to the stator and they both get hot.

1. I checked it with my VOM and Brian checked it with his completely seperate VOM. I'm sure there's no operator error. The 32 VDC at idle may be incorrect, I'm just going from memory. I'll check it again tonight. What should it be at idle ??

2. The temp of the 850 R/R may have dropped, but, after about 30 seconds of the bike running, it was still to hot for me to put my fingers on.

[Larry D]

Yep, my 82 GS1100GK. I used a FH012AA FET r/r with it and all is great! 14.5v (IIRV) at idle and stable throughout the rpms.

I asked pretty much the same Q's about mine last summer and Duanage, Steve, and Posplayer were quite informative- I learned a lot about it.

Seems our GKs are designed(?) with the higher voltage stators.

I don't have any problems whatsoever with mine. Of course, the r/r I have is actually for 50amp, IIRC.

Sorry, I didn't keep the writeups about it from last year. I put them in my threads, not realizing it would be purged



Really? Didn't you read your manual? It's this extra voltage that powers the Turbo mode

- JC

I'm sure the stator is an aftermarket one. There are 3 yellow wires that is sheathed in a fabric instead the different colored ones that Suzuki would have used.

TURBO ?!?!?!?!

Cool.

[posplayr]

If you have 100V RMS at 5000 RPM that is OK, but not nessesarily better. The GS charging systems are a balance of making the charging output match the demand as a function of RPM. As Steve mentioned , the faster you turn rotor the more power the startor can generate. So at high enough RPM's there is really too much power coming out that cant be consumed by the coils (for which power demand also goes up with RPM) and so the excess goes into heat keeping your R/R and stator toasty.

On the other hand at low speed idle, the higher voltage may be enough to keep from discharging because even though you will be far below 100 volts RMS, you might have just enough to keep from discharging at 1200-1300 RPM. Of course bumping the RPM will fix all.

The down side of the higher voltage (assuming it is a real measurement of a non-OEM stator) is usually that the higher voltage comes at the expense of lower current (as Steve stated higher voltage from more turns that are thinner with more resistance in terms of smaller diameter and longer length).

It is tough to make generalization beyond these simple principles because there are so many interaction when winding a stator. There are only so many wraps you can get onto a stator pole for a given wire size. Yes you can get more wraps if you drop the wire size, but depending upon the shape of the space around the pole and what size you are working with you will end up a much smaller wire, more insulation(taking up space) and the associated increase in resistance. This whole subject is really pretty specialized and difficult to gain a whole lot of advantage.

Electrosport claim a 20% increase in power output; it appears as if they are perhaps using a larger diameter wire. There is plenty of isulation on it for sure. This would tend produce more current but maybe not quite as much voltage at low RPM. This is where an FET based R/R comes in handly as it has lower voltage drop in it's full bridge rectifier (it doesn't use a full diode bridge) as so gives a little more voltage avaliable to charge at low RPM. The other benefit is that the FET R/R just drops less power so that extra 10-15 watts is avaliable for other things.

All in all I think this is about as good for a GS charging system can do and is what I'm running on my ED.

Peace

[posplayr]

2. The temp of the 850 R/R may have dropped, but, after about 30 seconds of the bike running, it was still to hot for me to put my fingers on.

This is after fixing the connections between R/R and battery?

What voltage drops do you have in Step #2 and Steps #3. I thought Bill said you were below 0.25V?


http://www.thegsresources.com/statorpapers4.php

Link to Revised PHASE A of Stator Pages:

[posplayr]

Seems our GKs are designed(?) with the higher voltage stators.

I don't have any problems whatsoever with mine. Of course, the r/r I have is actually for 50amp, IIRC.


- JC

If the GK stator was designed for 100 V RMS v.s. 80V RMS for most of the other GS stators, I'm wondering how they got it? If it physically larger? Or is it just would differently? Will the GK stator fit into a 1100E stator cover?

[TheCafeKid]

If the GK stator was designed for 100 V RMS v.s. 80V RMS for most of the other GS stators, I'm wondering how they got it? If it physically larger? Or is it just would differently? Will the GK stator fit into a 1100E stator cover?

I just did the stator/starterclutch/rotor, etc on a GK last summer. On the surface, the GK has the big rotor of an 1100E, but the starter clutch from a smaller GS (same size as a 750, but the bolt holes are not lines up right) The stator itself is interchangeable...

[Larry D]

This is after fixing the connections between R/R and battery?

What voltage drops do you have in Step #2 and Steps #3. I thought Bill said you were below 0.25V?

http://www.posplayr.100megsfree3.com..._Phase%20A.pdf

Yes, the 850 R/R still got very hot quickly after fixing the connections.

I don't recall what the voltage drops were with 850 R/R......I suppose I should've written it down. I do know that it got waaaay to hot for my comfort level. So, knowing it wasn't going to work, we hooked up the Honda R/R and all was good.

EDIT:: I feel I need to re-enforce the point that the stator is most certainly an aftermarket one of unknown origin....NOT the original one.