Number of stator poles question.

[chuck hahn]

Never knew whats the difference between a 12 and 16 pole stator. Ss it how much output difference there is or what??? Other than one having 3 leads versus 5 whats the difference???

[tkent02]

They all have three leads. It's 18, not 16. Just designed to be more efficient, make more electrical power at lower RPM I think, but it does need the correct rotor to work with it. The rotor has more magnets, which are smaller, to match the closer spaced poles in the stator.

Some electrical engineer will be along soon enough to provide more technical details.....

[chuck hahn]

16 ...18..... was wondering what the larger number did as far as power output. Im by no means into electrical crap, but Im trying to learn how to trouble shoot staors and rectifier issues..that sort of stuff that always perplexes me.

[tkent02]

I think there are 4 magnets in the 12 pole rotor, and 6 on the 18 pole rotor. The number of poles on the stator has to be a multiple of 4 or 6... The stator makes a little bit of current every time the magnet goes by each of it's poles. It's all wired together in such a way that when the rotor is spinning it makes a three phase AC current, hence the three output leads...

Chuck an hour or three spent reading about electrical power generation in general would probably help you more than looking at specific motorcycle parts at this point.

[Steve]

The biggest difference between the two stators is the size of the "ripple". As each magnet passes over a stator pole, there is a peak in the current produced. Since there are multiple poles, this happens as a series of peaks. The more poles you have, the smoother the power. It's kind of like listening to the difference in sound in a twin, a four and a six. If the displacement were the same, the power would be close to the same, but the sound would be smoother.

In a nutshell, the GSes that had kickstarters had 12-pole stators, those without kickers had 18-pole stators. Might have a bit better charging to replenish the battery quicker after using the mandatory electric starter.

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[tkent02]

In a nutshell, the GSes that had kickstarters had 12-pole stators, those without kickers had 18-pole stators. Might have a bit better charging to replenish the battery quicker after using the mandatory electric starter.

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Not true, the early 550s had 18 poles and a kickstarter.

[1980GS1000E]

OK, so I am wondering... My bike, a 1980GS1000E, has what type and I did replace the stator a few years ago with Rick's unit. Could they have sent the wrong one? My charging output is not the best, barely charges the bike. Voltage goes up to about 13.7-14 and I am running the SH775. I have new, clean connections. If the stator is different than the rotor as far as 18 vs 16, would there be any charging output at all or would there be a reduced amount?

[tkent02]

With 18 pole stator and a 12 pole rotor, I don't think it would really charge at all. There is no 16.

[1980GS1000E]

I meant 12. D'uh.

[tom203]

OK, so I am wondering... My bike, a 1980GS1000E, has what type and I did replace the stator a few years ago with Rick's unit. Could they have sent the wrong one? My charging output is not the best, barely charges the bike. Voltage goes up to about 13.7-14 and I am running the SH775. I have new, clean connections. If the stator is different than the rotor as far as 18 vs 16, would there be any charging output at all or would there be a reduced amount?

Best to check the ac phase to phase voltage and phase to ground voltage with the r/r disconnected from stator. Your stator might be partially shorting out to ground interfering with the r/r's ability. My previous stator behave like this.... charging never got much higher than 13.5 at any rpm.

[JTGS850GL]

I've seen 1980 GS1000's with 12 pole stators and 18 pole stators. They never made a kick start 1000. Since it's a 3 phase system the number of poles/magnets must be a multiple of 3. Thus the 12 and the 18 poles. Easy to verify what stator you need. Remove the stator cover and run a screw driver around the inside of the rotor. If the rotor magnet grabs the screwdriver 12 times then it's a 12 pole stator. If it grabs it 18 times then it's an 18 pole stator. There must be the same number of poles as there are magnets or there will be no power generation.

[Steve]

Not true, the early 550s had 18 poles and a kickstarter.

I just looked at all the fiches for the 550s at Alpha Sports. All of the 550s shown there had 12s, including the '80, which was the first year without a kicker.

Not sure if anyone else's fiche would show anything different, but it's possible. I have not done nearly as much work on 550s as you have, I am just going on what I have observed.

.

[Steve]

I've seen 1980 GS1000's with 12 pole stators and 18 pole stators. They never made a kick start 1000.

I will agree that they never offered a kick-start 1000, but the parts fiche at Alpha Sports for the '78 and '79 1000s all show 18-pole stators.

Not sure if anyone else's fiche would show anything different, but it's possible.

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[JTGS850GL]

The last 1980 GS1000GL I worked on had a 12 pole stator and flywheel. I know because I wanted to use the stator on a different motor but it obviously was wrong.