GS Stator

[uk gs nut]

I had an ELECTROSPORT RR10 short to earth and blow main fuse, TOP quality goods. NOT!.

[Brendan W]

It was probably Jim who made me aware of this way of looking at things. My lightbulb moment was realising that the stator and r/r run the bike like a mini power station. Like many folks I would have seen the battery as supplying all current and the charging system continually refilling it. The battery is an APU off to the side and like every other circuit needs to be fused. It has other filtering functions but it's better to see the main earth point as the r/r return, not the battery negative, and the main supply point the r/r positive. Things will only get better when all returning currents, including battery charging current are as close as possible physically and potential-wise to the r/r return, hence spg.

[Gorminrider]

Not trying to be a troll here, and new is often better in electronics, but I rode for years with bikes with old regulators and had no issue. There are several ways to burn out a stator and and r/r that don't involve "series" or "shunting"-fixing any shorts and replacing bad batteries, having a well-made regulator that is well-cooled (and maybe of a larger current carrying capacity than the stator can produce) are other things to do.. Likewise, keeping the oil up to the mark....otherwise improving cooling on the stator itself might also be a help, given heat is the issue
....and more: it would seem that the stator windings act a bit like an oil filter, collecting sludges that might insulate it and impede cooling...and low temperature wire coatings get brittle over time- that's a weakness I note in Suzukis, but it points to "cooling" too.

But I digress from a point that heretofore seems to border on hysteria: "Shunting".
The stator on my bike is mostly supplying the "live loads" like headlight, tailight and coils and even a bit to the battery. There is little left to be "shunted" through stator.* So, some heat will be made in your stator whether shunt or series.
Also, (whether "series" or "shunt") this live load passes through the R/R's diodes and the voltage drop there must produce heat. .....Increased efficiency of an fet gate no doubt is a good thing but isn't the 1/2 volt drop always there? and therefore the wattage based on this "live" load?

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 can imagine a few other points of interest, like a voltage spike in the stator when the series R/R "opens", but as to whether this is true or important, I do not know....

*if you are running leds everywhere, you will be more concerned with "shunts" than I am I suppose.Your duty cycle(?) will be less.

[Nessism]

But I digress from a point that heretofore seems to border on hysteria: "Shunting".
The stator on my bike is mostly supplying the "live loads" like headlight, tailight and coils and even a bit to the battery. There is little left to be "shunted" through stator. So, some heat will be made in your stator whether shunt or series.

I can't find the info at the moment but have looked previously, and the amount of excessive power produced by the stator that can possibly be shunted back on itself is only something like 50 watts if using a stock Suzuki stator. 50 Watts isn't all that much. 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.

Needless to say, once a stator starts to age and it's insulation resistance starts to break down it will be more prone to failure. But at the same time the power output typically drops then as well so there isn't much excess current to heat the thing up which extends the life.

It's a complex balance and hard to predict. Personally, I"ve got series R/R's on both my bikes, but frankly I was never overly worried about my bikes charging system when using a shunt type R/R, especially since I'm not using a high power stator.

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.

PS: Case in point story: I was helping a fellow GSR member fix his charging system. This was an older bike with separate regulator and rectifier. We ditched that and wired in a FH008 R/R (MOSFET shunting type). The stator was weak and all we could get out of it was about 13.5 volts. Sent the member away with the warning that the charging system was weak but at least it was improved from where it was. He was to keep using the bike and see what happens and I haven't heard from him since.

[posplayr]

Not trying to be a troll here, and new is often better in electronics, but I rode for years with bikes with old regulators and had no issue. There are several ways to burn out a stator and and r/r that don't involve "series" or "shunting"-fixing any shorts and replacing bad batteries, having a well-made regulator that is well-cooled (and maybe of a larger current carrying capacity than the stator can produce) are other things to do.. Likewise, keeping the oil up to the mark....otherwise improving cooling on the stator itself might also be a help, given heat is the issue

....and more: it would seem that the stator windings act a bit like an oil filter, collecting sludges that might insulate it and impede cooling...and low temperature wire coatings get brittle over time- that's a weakness I note in Suzukis, but it points to "cooling" too.

I fully agree with your conclusion but only 1/2 of your supporting analysis. Series v.s.Shunting is the largest factor when considering whether your stator will burn up or not. I have documented a 3:1 differential power dissipated in the stator under SHUNT v.s.SERIES control. Very few will understand how this calculation is done although everything needed to understand it is listed in the charts below. You will just have to take my word (or not).

http://www.keepandshare.com/doc/4066862/ssr-vs-fh012aa-pdf-may-31-2012-10-20-pm-903k?da=y

It is certainly not the only factor and there are other ways to keep the stator cool as in direct oil sprayer. There are other arm chair analysis on why a stator can not substantially increase operating temperature but there are enough people having posted the fact and I have seen it first hand on my own bike to know it is a substantial factor in oil operating temperatures from big block engines. That alone is a very compelling reason to go Series over shunt

But I digress from a point that heretofore seems to border on hysteria: "Shunting".
The stator on my bike is mostly supplying the "live loads" like headlight, tailight and coils and even a bit to the battery. There is little left to be "shunted" through stator.* So, some heat will be made in your stator whether shunt or series.
Also, (whether "series" or "shunt") this live load passes through the R/R's diodes and the voltage drop there must produce heat. .....Increased efficiency of an fet gate no doubt is a good thing but isn't the 1/2 volt drop always there? and therefore the wattage based on this "live" load?

If you took the time to use Ohm's law (V=IR)and actually quantify your analysis you would realize you are barking up the wrong tree. There is no point even discussing your points without putting numbers to them. I have done that in the past, but apparently this discussion is eluding those analysis.

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.

I can imagine a few other points of interest, like a voltage spike in the stator when the series R/R "opens", but as to whether this is true or important, I do not know....

*if you are running leds everywhere, you will be more concerned with "shunts" than I am I suppose.Your duty cycle(?) will be less.

As an Electrical engineer with a Masters Degree and with over 30 years electrical design, system design , analysis as well as substantial effort expended in understanding the interworking of motorcycle changing systems in particular SHUNT PM charging, it is my opinion that continued delivery of motorcycles with SHUNT R/R even up to the most recent last 5 years has been one of the most significant design defects perpetrated on the general motorcycling public of any and all shortcoming that most motorcycles would seem to have.

[posplayr]

I can't find the info at the moment but have looked previously, and the amount of excessive power produced by the stator that can possibly be shunted back on itself is only something like 50 watts if using a stock Suzuki stator. 50 Watts isn't all that much. 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.

Needless to say, once a stator starts to age and it's insulation resistance starts to break down it will be more prone to failure. But at the same time the power output typically drops then as well so there isn't much excess current to heat the thing up which extends the life.

It's a complex balance and hard to predict. Personally, I"ve got series R/R's on both my bikes, but frankly I was never overly worried about my bikes charging system when using a shunt type R/R, especially since I'm not using a high power stator.

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.

My calculations are it is in excess of a 200W differential. I posted the results and the methodology in the link above. 125W with SERIES and 350 watts with SHUNT in the stator.

[Nessism]

My calculations are it is in excess of a 200W differential. I posted the results and the methodology in the link above. 125W with SERIES and 350 watts with SHUNT in the stator.

Jim,
My Kawasaki's stator produces 238 watts total (can't find a number for stator output in the Suzuki manuals). How can there be 200 watts of "extra power" (or are you suggesting 350 watts?) shunted back into the stator?

The ignition system uses at least 10A (120 Watts), the head lamp is 50 watts (low beam), add in tail lamp, brake light, turn signals, instrument lights, and you are pushing 190 watts easy, which means there is (maybe) 50 watts extra.

[tom203]

My crude clamp- on ammeter showed theoretical output of 270 watts at 4000rpm using a shunt SH-232. With the series SH-775 output dropped to 170 watts (that's all bike needed to run everything). If you opted for a 20 watt led headlight, the SH-775 would likely drop that output to 130 watts .

[Nessism]

My crude clamp- on ammeter showed theoretical output of 270 watts at 4000rpm using a shunt SH-232. With the series SH-775 output dropped to 170 watts (that's all bike needed to run everything). If you opted for a 20 watt led headlight, the SH-775 would likely drop that output to 130 watts .

So that's what, 100 watts max of extra power?

BTW, what kind of stator do you have?

[posplayr]

Jim,
My Kawasaki's stator produces 238 watts total THAT IS ONLY THE OUTPUT DELIVERED not the TOTAL PRODUCED; HAVE YOU CONSIDERED CONVERSION LOSSES? WHERE ARE THEY? IT IS NOT A PERFECT SYSTEM(can't find a number for stator output in the Suzuki manuals). How can there be 200 watts of "extra power" (or are you suggesting 350 watts?) shunted back into the stator?

The ignition system uses at least 10A (120 Watts), the head lamp is 50 watts (low beam), add in tail lamp, brake light, turn signals, instrument lights, and you are pushing 190 watts easy, which means there is (maybe) 50 watts extra.

Ed,
I know I have never described this but it is basically first principles of electrical engineering. The TOTAL power generated by the charging systems can be divided logically, physically and analytically into three components. Power dissipation in:

1. The stator (350W shunt v.s. 125 watts SERIES)
2. The R/R (25-50 watts depending upon SHUNT SCR (highest) v.s. MOSFET (lower) v.s. SERIES SCR (SH-775) and the lowest being MOSFET SERIES(Compufire))
3. The load (including the all electrical components and the battery) is what is specified in the manual and is generally 14-15 amps at 14.5V or 203-217.5watts delivered.

Strictly speaking you can add the wiring between the R/R and the battery as a separate item from the load as well.The Spec sheet only gives you the rating for item #3. Items #1 and #2 are not specified.

What I described, calculated and documented is item #1. For shunt it is 350 watts.

I would have to look up the specific voltage drops to estimate what #2 is but I don't have those figures readily at hand. Regardless it is also not specified.

Jim

[posplayr]

Realize my numbers are not exact they are approximate but they are almost guaranteed to be much higher. I would not be surprised if it was 50% more.

The only way to actually measure the power dissipated in the stator is to measure the current in a leg (we we can) and multiply it in real time by the voltage across the leg (my scope does this). However, that is a leg to neutral measurement not a leg to leg measurement which is shorted(i.e. non ideal zero volts). The neutral does not come out without modifying the stator specifically for the test. I did not bother. It is at least 3 times the power.

For the plots, I used a first approximation instead relying on ohms Law for power P=I^2R and used the room temperature spec stator resistance (or maybe measured it with an ohm meter) as an estimate. Again however, as the stator heats the resistance goes up meaning power would be proportionally higher for the same measurement.

So the plots are very conservative in estimating the power differential between SHUNT and SERIES. Shunt will be much higher depending upon how much higher hotter the stator is over room temp.

[posplayr]

My crude clamp- on ammeter showed theoretical output of 270 watts at 4000rpm using a shunt SH-232. With the series SH-775 output dropped to 170 watts (that's all bike needed to run everything). If you opted for a 20 watt led headlight, the SH-775 would likely drop that output to 130 watts .

Tom how did you convert current into watts?

[tom203]

So that's what, 100 watts max of extra power?

BTW, what kind of stator do you have?

My test was at 4000 - there's likely a bit more as you climb to 5000 rpms, but stator is pretty saturated at this point due to the high frequencies. I used a stock suzuki stator off a 81 gs650 (used not new!)

you might find this link interesting.... Involves output increase in 250 ninja charging system

http://faq.ninja250.org/wiki/Alternator_Information

[Nessism]

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 280 watts or so (from a stock stator). Maybe the reason you were frying stators all the time is because you were using Electrosport HD stators?

[Nessism]

you might find this link interesting.... Involves output increase in 250 ninja charging system

http://faq.ninja250.org/wiki/Alternator_Information

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