The Next Nerobro's HowTo: Doing the Stator Dance

[SPARKSS]

I've tried rewinding my own Stator but things aren't going too well.

The first one failed for understandable reasons when a couple of windings chafed on the rotor, leading to an intermittent ground. But I was very careful with the second rewind and did it very neatly with only 35 turns, as opposed to the original 50 and this clears the rotor without trouble. Resistance according to my multimeter is about 1.2 ohms from any one yellow wire to any other. Resistance to ground is > 2 M ohms. Resistance from a yellow wire to the union of the three wires at the opposite end of the stator windings is about 1.0 ohms. Resistance with just touching probes together is about 0.7 ohms. The multimeter looks to be exactly the same as that used by Nerobro with a different colour scheme but all the same switch positions and ranges.

I would therefore correct the real resistances to the following:

Yellow wire to yellow wire: 0.5 Ohm
Yellow wire to union at end of stator 0.3 Ohm
Yellow wire to solder joint at start of stator ~ 0.1 Ohm

Basically this all seems to make sense. The total resistance seems a little low but the magnet wire is a heavier gauge than that used in the original (I used the following).

The output in AC volts from one yellow terminal to another is about 1 V at 4000 rpm and changes a little with RPM. But this is never going to charge my battery. What could I be doing wrong?

Could the insulation of the magnet wire be failing and allowing each coil to short out? Could I have damaged the insulation in winding?

Could something else be wrong that I haven't thought of?

BTW: I have checked the rotor. This seems to show alternating north and south poles facing inwards all the way round the rotor. Also, when I put the LHS cover on with the stator attached, it is pulled in strongly by the magnetic attraction. So, I don't think there's anything wrong with the rotor.

Thanks

Ian

Howdy Ian. Your resistance readings look ok. Don't get too hung up on whether a winding "measures" a couple of hundred mohm one way or the other. Your reading showing >2Mohm to ground is more important and indicates, in all likelyhood that you're not chaffed badly either (as the likelyhood of a path to core...ground is most great). Even with many turns shorted, a short to ground and perhaps only one phase roughly intact, you'd have more than 1v AC between 2 line-line connections so this is a puzzler. You have MORE THAN ENOUGH wire wound to satisfy the output (I never wind that much). My first thought was that you might have measured using a DC meter........this will show erroneously because the source is AC (of course).
If that's not the case........and you've wound 18 poles with the 3 phases symetrically interspaced, then consider whether you have EACH POLE WOUND IN THE SAME DIRECTION - this is important........if, for example you found that it seemed to fit better to wind one one way and when you moved to the next, the other, then you'll set up a situation where the individual cycles are equal and opposite - bad juju......poor/no output.

 

[maclariz]

Rotor/Stator incompatibility

Rotor/Stator incompatibility

Well, I spoke to someone from Electrex today. He said that running a 12 pole rotor with a 12 pole stator will not work. I was thinking this was probably the case from some back of envelope calculations. In this case, all the wires produce volts in phase, and you get no potential difference between the pairs of wires.

His summary was:
For a 12 pole rotor you need an 18 pole stator.
For a 12 pole stator you need an 8 pole rotor.

Basically for every three poles on the stator, you need two magnetic poles on the rotor. This puts all three phases at 120 degrees to one another.

So, I've ordered the 18 pole stator from Electrex and I hope that this combined with my 12 pole rotor will start the thing charging again. I'll report back once I've fitted and tested it.

How the bike ended up with an incompatible rotor:stator pair is another mystery that will be down to one of its previous owners. I suspect that the stator broke and was replaced with a used one off another bike, which wasn't actually compatible.

 

[Matchless]

Well, I spoke to someone from Electrex today. He said that running a 12 pole rotor with a 12 pole stator will not work. I was thinking this was probably the case from some back of envelope calculations. In this case, all the wires produce volts in phase, and you get no potential difference between the pairs of wires.

His summary was:
For a 12 pole rotor you need an 18 pole stator.
For a 12 pole stator you need an 8 pole rotor.

Basically for every three poles on the stator, you need two magnetic poles on the rotor. This puts all three phases at 120 degrees to one another.

So, I've ordered the 18 pole stator from Electrex and I hope that this combined with my 12 pole rotor will start the thing charging again. I'll report back once I've fitted and tested it.

How the bike ended up with an incompatible rotor:stator pair is another mystery that will be down to one of its previous owners. I suspect that the stator broke and was replaced with a used one off another bike, which wasn't actually compatible.

How did you determine the amount of magnetic poles in the rotor? I have a rotor with 3 physical magnets fitted and the stator has 18 poles. The 12 pole stator will have a rotor with 2 physical magnates fitted.

 

[maclariz]

How did you determine the amount of magnetic poles in the rotor? I have a rotor with 3 magnets fitted and I think the stator was 12 poles, but not sure, as it has already been refitted. The theory sounds good, but I was wondering how to identify this easily if running around junk yards in future.

Yeah mine has 3 magnets too, but testing with a small fridge magnet, you will get strong attraction from one pole, strong repulsion from the next and so on. Each of my magnets had two areas of strong attraction and two of strong repulsion along it's circumference, i.e. 4 poles altogether.

As far as I can see, if you have 3 magnets, no maths using whole numbers can make this into 8 poles, but it is easy to make this into 12 poles. To have an 8 pole rotor, you would need two or four magnets mounted, so you can probably do it by visual inspection. But a small fridge magnet in the pocket is an easy way to be sure.

 

[mixongw]

Neropro: 18 awg. is thinner than 16 awg.

 

[TheCafeKid]

I was just glancing thru this, and noticed a couple of things.

One: the 83 550ES Stator is the SAME stator that is in the 1000G (E too?) 1100G/E. The big 18 pole stator. There were, AFAIK only THREE different stator types used by Zook. The old 12 pole, with a 6 "pole" rotor (3 neg, 3 pos) and then they went to an 18 pole stator, with a 9 pole rotor, and then a LARGER 18 pole and larger 9 pole rotor. There is, for lack of a more technical term, as im no electrical wizard, an on and off for each pole of the rotor on the stator, or vice verse. However many windings there are, there are HALF that of positive mags in the rotor.

TWO: As far as ive found, NO ONE makes a replacement stator for the old 12 pole stators. You're only real options are to re-wind it yourself, OR switch the stator AND the rotor to the 18/9 small set up, say from an 850, or a later 750 or something like that. AFAIK there were only TWO different crank snout diameters, the biguns, and the smalluns. ANything that uses the SMALLER stator, 18 pole or not, should be able to be converted to any OTHER small snout set up, with the proper bearings and what not. At least I would ASSUME so (and we all know where that gets you)

 

[loudest143]

I just wanted to say thank you in advance for this thread. I've had a problem with my stator for a little while, and was lamenting the replacement cost. (i'm in the middle of a divorce, so money is super tight) Seeing this thread, and all of the awesome photos, I'll be winding my OWN this week. I actually like doing fun little electrical projects, and am looking forward to doing this.

Nero, I think you mentioned you thought the OEM wire was 20AWG. Do you feel that's correct? I'm gonna look for both 20 and 18, but just thought I'd ask if you knew for sure at this point.

Also, do you have any updates to report? Still working well?

THANKS SO MUCH!

loudest143

 

[Nerobro]

Becuase I just found this thread again, I thought I'd mention that my bike is still running my home spun stator. The RR I had on there was charging a bit low... so I swapped that out again. But, otherwise, the bike has been great.

 

[Pchitti]

Great write up.

Great write up.

Great write up. Thinking about going this route and I believe this thread just made it certain, could still buy one if money randomly ends up in the pocket....

Any suggestions on wire? Places to buy the wire.

 

[koolaid_kid]

Great write up. Thinking about going this route and I believe this thread just made it certain, could still buy one if money randomly ends up in the pocket....

Any suggestions on wire? Places to buy the wire.

Yes, I did this for my bike this summer. Let me find the links I found and I'll post them. I was not able to build the fancy looking wiring that nerobro made, but it works great. The biggest hassle I had was finding the epoxy. Although if you go nerobro's route and don't use any, the point is moot.

 

[Matchless]

Here is a link that may help you decide: http://www.mediafire.com/?jm3lzukjzyt

 

[koolaid_kid]

Here are a couple of links for the stator winding wire:
http://www.bulkwire.com/wire-cable/magnet-wire.html
http://www.planetengineers.com/default.asp?cat=Wire,+Magnet&gclid=CIGJhPiMtqMCFRRsswod7wQrcA
I used 18 gauge, and was able to get about 30 winds per pole, which is what the OEM stator had also.

If you need to replace the high temp insulated wires, here is a source:
http://www.hrpworld.com/googlebase...._id=,133,717,238,717,133,_4192&action=product

Both can also be found on fleabay for comparible prices.

When I finally got down into it, I used Matchless' writeup almost exclusively, with just a smattering of the nerobro thread thrown in for added flavor.
Two things that may be of interest: I found the clothespins to be crucial for a tight wind and for aligning each wind (you'll understand when you get there), and I bought a cheap pair of mechanics gloves at Harbor Freight and wore those whilst winding. No damage at all to delicate fiingers, although the gloves were trashed by the end of the project.
I also suggest that you purchase plenty of winding wire; I had several do-overs before I got the hang of it.
Best of luck, it does work.

 

[Matchless]

When I finally got down into it, I used Matchless' writeup almost exclusively, with just a smattering of the nerobro thread thrown in for added flavor.
Two things that may be of interest: I found the clothespins to be crucial for a tight wind and for aligning each wind (you'll understand when you get there), and I bought a cheap pair of mechanics gloves at Harbor Freight and wore those whilst winding. No damage at all to delicate fiingers, although the gloves were trashed by the end of the project.
I also suggest that you purchase plenty of winding wire; I had several do-overs before I got the hang of it.
Best of luck, it does work.

Nerobro's guide was my initial inspiration and a pair of pigskin gloves work well.

 

[koolaid_kid]

Nerobro's guide was my initial inspiration and a pair of pigskin gloves work well.

Yeah, except for the pig.
But seriously, combining the two made the job as easy as it could have been made. I was never able to get the hang of nerobro's mushroom windings. Not sure how he made the transitions in the middle, so I just went up and down and up and partway down like Matchless. It made for really tight clearances at the base where space is at a premium, but it are workiing. And the HF gloves were $2, not a big deal, and no animals were injured in this commercial.

 

[koolaid_kid]

One thing I had trouble finding was the high-temp epoxy. Griffin got some for me from his (former) place of work. It was weird to work with: When I mixed the catalyst with the resin, it waited about 30 minutes as a liquid and then suddenly got really hot and set up as a solid. The heat caused havoc with my plastic mixing bowl - I was glad I was there to take the bowl and hurl it outside. The next stator I did I used a soup can and everything was fine. I was able to find this on fleabay: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=310180741247&ssPageName=STRK:MEWAX:IT
It is a huge quantity, but I plan on doing more of these, so it is O.K.
Also, I purchased my wire off fleabay as well. I got 11 pounds for around $100. I actually wish I would have purchased 19 gauge as the 18 gauge was still a bit difficult to work with (kind of stiff and difficult to bend, although the clothespins saved the day).
Just a thought.

 

[Matchless]

I got all my stuff from a supplier to the rewinders. The rewinding places are only familiar with what they use.

 

[Nerobro]

I didn't use epoxy to seal my stator. It still is within spec.

 

[koolaid_kid]

I didn't use epoxy to seal my stator. It still is within spec.

Absolutely. It is my understanding the epoxy is only for helping with vibration, electrically it is neutral.

 

[posplayr]

Absolutely. It is my understanding the epoxy is only for helping with vibration, electrically it is neutral.

The epoxy also stops the windings from flexing as the electromotive force pushes on the winding as the stator generates power.

If left to flex, they would wear through the insulation and short.

Interesting Nerobro did not use any; it suggests that the stators doesn't create that much power or he did a really good job winding and securing all the windings.

250 watts is about 1/3 of Hp

 

[koolaid_kid]

Interesting point on the flexing, that makes sense.
If you look at his pics, his windings are really tight and clean. I was not able to duplicate them. That could be why his stator is holding up? IDK, merely conjecture.