GS Stator

[posplayr]

Jim, my Kawasaki manual states "maximum alternator output" at 238 watts.

If as you say, and I believe you, the vehicles consumption is 203-217.5 watts, that leaves roughly 20-40 watts extra to be returned to the stator.

These charging systems are permanent magnet, so as I understand it they will produce the power whether the bike needs it or not.

It's certainly possible that a Suzuki GS stator makes more than 240 watts, but I don't think it's more than 270 watts or so.

You apparently do not believe me. They are only specifying total delivered to the load. It is also very easy to measure this as I have done.

This does not include heat losses in the R/R or the stator.

[Skowinski]

Eating popcorn and watching here, always up to learning new stuff!

[tom203]

Tom how did you convert current into watts?

I took an overly simple approach.. As usual

In balanced 3 phase power.......P=1.73VI
where I is the measured leg AC current and V is the Dc voltage of the r/r output.
with the shunt unit I=11amp... with the series I=6.8 amp
V was 14.2 volts in both tests.

[tom203]

Stock stator was 180W, high powered aftermarket stator was 300W. No wonder the aftermarket stators fry out.

yes, but the 300 watt unit required case mods as it was thicker.

[posplayr]

I took an overly simple approach.. As usual

In balanced 3 phase power.......P=1.73VI
where I is the measured leg AC current and V is the Dc voltage of the r/r output.
with the shunt unit I=11amp... with the series I=6.8 amp
V was 14.2 volts in both tests.

Unfortunately you are mixing stator current with DC output voltage.
We know for a Series R/R that the average stator current is going to be proportional to the DC output current whereas that relationship is more complementary shunt (rising DC current decreases stator current).

To turn this current into power you either need the stator resistance or the stator leg to neutral voltage.

[Nessism]

You apparently do not believe me. They are only specifying total delivered to the load. It is also very easy to measure this as I have done.

This does not include heat losses in the R/R or the stator.

I believe you measured power...and your bike had one of those high powered stators too...which burned to a crisp.

[posplayr]

I believe you measured power...and your bike had one of those high powered stators too...which burned to a crisp.

You can believe this as well.
I should add for total redundancy that the 14-15 amps I quoting is not a constant. It is a nominally charged battery with bike at approximately 3500 RPM headlamp, tail lights BUT with blinkers and brakes OFF without other accessories.




Ed you make it very laborious having to repeat the same information over an over again. I would have thought you would have remembered by now that the total maximum output of a stator can not be changed by rewinding it short of not winding it. It is completely determined by the rotor which I did not change.

[WolfworksCustoms]

If anyone needs another stator, I strongly suggest contacting Tim Parrot... http://tpe-usa.com/

...you get a higher output, etc....and his prices are great....a LOT better than some of those offered on Ebay, btw....this guy knows his stuff....

[tom203]

The higher the stator output, the more you need a series r/r. Member Steve also has a rewinding guy.

[Gorminrider]

Originally Posted by Gorminrider

and then there's a few oddities that make me wonder:
if you goto the link offered in post 31 http://www.thegsresources.com/_forum...97#post2130797 and look at the pictures of the Stator heat, you will note a discrepancy in the colour scale. The white Hot of the series colour scale picture is 174C while the upper whitehot of the original shunt is 150. This means the series will appear somewhat cooler, I think.

3) isn't this Aprilia in the above example (an Aprilia) water cooled? a detail per "stator heating" might be how long the bike was running before each heat-picture was taken.

I think that was the point of the pictures.

So do I, and that's what worries me. the 'original" appears to be hotter due to the "white hot" being 150c versus the new regulator with 'white hot' being 174c. It occurs to me both pictures would be more similar using the same scale. I'm not impugning the author but when I test things, it's always pleasing to get the results I am looking for, if you know what I mean...

File: IR Lima cover original Spannungsregler.jpg





File: IR Lima cover Compu-fire.jpg

[posplayr]

Please allow me to interpret the graphs........................


In German, Messpunkt means "measuring point". You will note that in the upper lefthand corner the original is 114 degC and the Compufire is 97.7 degC. That is a 16.3 degC differential. In something more familiar to us not use to Celsius, 117degC converts to 242.6degF and 97.7 converts to 207.9 degF. That is a 34.7 degF differential.


From looking at the image and the reticle centered on the stator (as well as the high resolution of the image) I think it is safe to say that the Messpunkt, is an average in the near region of the center retical. This does not imply that the engine oil will be 34.7 degrees cooler using the Compufire, but that the stator is running substantially hotter with the shunt R/R.

The fact that the image temp autoscaled does not preclude a comparison of the images, but in fact none is nessesary as the Messpunkt reading tells you the absolute differential at the stator cover center.

[posplayr]

Stock stator was 180W, high powered aftermarket stator was 300W. No wonder the aftermarket stators fry out.

There is more to those numbers than what Electrosport is marketing them as. The maximum current is always limited by the rotor. You can't change the stator and get more peak current. I would say the chart is an outright lie but I can not detect the caveats being applied to the data where it might be not so blatant.

The much heralded 20% increase power that Electrosport claims on their stators is only at RPM's below peak current.


In simple terms the motor is making ever more power available to the charging system with increased RPM. In fact the power available is going up as the square of the velocity (i.e. RPM). So why does it flat line? What happens to the "conversion efficiency". The answer is that the rotor magnets can only support so much current. Once you get to that peak no matter how fast you spin the rotor you only get out so much current.

So any two stators will both hit the same peak current. Depending upon how they are wound the only differential will be in at what RPM that occurs. The high output stator will do it at a lower RPM.

[Gorminrider]

On the other hand, purchasing a shunting R/R borders on lunacy in this day and age since series R/R's are readily available and cheap. May as well.

nessism, I have 3 suzukis, 1 Honda . I guess it depends what you consider to be "cheap". Tires come first. All have shunt r/r's. All work fine. 3 get considerable use-200km rides are common for any of them in the summer and for the Honda, 2000 km on occasion.....only the Honda has its original stator and the original shunt R/R
I have replaced all 3 Suzuki stators and only one of these has its original R/R ( a 650 that has not yet been broken in) One even has a $22 ebay generic shunt RR that seems to be hanging in there....

I think where people get into big trouble with cooked stators is when using one of those "heavy duty" type stators (like an Electrosport) that produce more power than stock and too much power for a normal GS to consume, thus the stator winds up cooking itself.

Nessism, this is an interesting point ..... When people are busy converting to LEDs on one hand and then going for Heavy Duty-Hi-Output stators on the other hand, they are making some kind of mistake, unless they are running other hi loads as well- a heated vest and gloves maybe.
It even got me to think of the much unloved "stator loop". Imagine if a stator leg WAS dropped when output overmatched the loads. Or when an led'd bike was not needing the rider's heated vest....Perhaps using a relay versus the original long-wire to a headlight switch....

[posplayr]

Nessism, this is an interesting point ..... When people are busy converting to LEDs on one hand and then going for Heavy Duty-Hi-Output stators on the other hand, they are making some kind of mistake, unless they are running other hi loads as well- a heated vest and gloves maybe.
It even got me to think of the much unloved "stator loop". Imagine if a stator leg WAS dropped when output overmatched the loads. Or when an led'd bike was not needing the rider's heated vest....Perhaps using a relay versus the original long-wire to a headlight switch....

You are absolutely correct on both points. In fact there are several posts and discussion warning about LED modifications without changing to a SERIES R/R else your SHUNT R/R will overload the stator and burn it out.

As far as matching output to load you are also absolutely correct, Suzuki started doing this 40 years ago except unfortunately the accumulated environmental exposure was too much for the connector and switches to endure. I'm sure a modern stator leg loop relay modification could be developed but you better look for a high voltage relay; probably Solid state to stay in this century.

Of course anybody looking to just solve the problems and move on would simply just install a SERIES R/R and all these revelations, and workarounds would become mute.

[Nessism]

Electrosport has this little blurb on their website where they mention how dropping out one leg of the stator cause "imbalance" in the system. Might be more BS, not sure, I'm not sure what the real world effect this has either. I do know I'm not a fan of high output stators though. I'm no expert on the subject but I do know that the number of turns and the size of the wire influences output when winding stators. The strength of the magnets is also a factor in how much current is generated and at what rpm. I think that Kawasaki's KZ bikes have lower output charging systems than Suzuki GS's, and they don't seem to have as many failures. Less output current flowing through the stator causing insulation breakdown for one, and less shunted current going back for another. Sort of counter intuitive to improve the system by downgrading the output but that's the reality.