750 twin stator

My stator has been on the way out for over a year (battery charger has been busy ). I purchased a new one recently from DK but it turns out to be incorrect for my bike (3 yellow wire I have 2)- I checked with the maker (who supplies DK) and apparently they have it incorrectly listed on their web site and do not make one for the 750 twins.

Any way its on its way back to the USA and I'm on the hunt - I do have a second hand one (in theory it will be OK) but figure I'd rather put a new or rebuilt one on.

So does anyone know of anywhere in the world these stators can be rebuilt/wound? No one in New Zealand apparently.

Thanks

Allan

You can use a three wire stator (as long as it fits) by switching to a three wire reg/rec. It would probably be a good idea to do so, as the two wire versions are getting scarce.

When you had the new three wire stator and the used two wire stator, did you compare the two, as to physical size and mounting bolt location? Were they the same OD, and did the bolt holes line up? If you did not compare them, then let me know and I'll go to the garage and dig up a 750 four stator and a 750 twin stator, and do the comparison. If they are the same, I think I'll open up the 750 project motor and switch it over

Keep us posted on the possible switch to 3 phase charging system, that would be a nice addition with possibly more charging current thus keeping battery fully charged easier. as you know the 76 and 77 had the 3 phase but used a field coil also.

I just compared a 83 GPz750 stator (same size as a 2 wire 650 stator) to a 750B stator, and the bolt holes line up, but unfortunately the GPz750 stator is about 3/8" smaller in outer diameter (eyeballing it, GPz stator laying on top of 750B stator).

I think that kills the swap idea, but I hope Lou (Loudhvx, AKA the electrical guru) will post to either confirm or deny my conclusion.

I PM'd Lou, so hopefully he will post his opinion on the subject the next time he is online.

Post edited by: steell, at: 2005/10/23 15:09

I have a link to a company in the USA who rebuilts them but as of yet no reply to my e-mail. Will keep posted.

Allan

AllanB wrote:

I have a link to a company in the USA who rebuilts them but as of yet no reply to my e-mail. Will keep posted.

Allan

Since you mentioned companies that rebuild, I used a company in Canada that did a great job. Quick turn-around, too.

I got my stator rewound at R.M Moto Électronique ... wow, it looks like they just re-did their website...

Post edited by: biquetoast, at: 2005/10/25 08:41

steell wrote:

I just compared a 83 GPz750 stator (same size as a 2 wire 650 stator) to a 750B stator, and the bolt holes line up, but unfortunately the GPz750 stator is about 3/8" smaller in outer diameter (eyeballing it, GPz stator laying on top of 750B stator).

I think that kills the swap idea, but I hope Lou (Loudhvx, AKA the electrical guru) will post to either confirm or deny my conclusion.

I PM'd Lou, so hopefully he will post his opinion on the subject the next time he is online.<br><br>Post edited by: steell, at: 2005/10/23 15:09

Oops. Sorry, I didn't know I had a PM til today.
If the GPZ stator is smaller, then I assume it will fit inside the rotor, unless there is some other interference. Then the only issues are the gap between stator and rotor, and the number of pole-pieces on the stators.

I am only familiar with the 3 phase 550 alternators, but the concept is the same.

The gap is self explanatory. Bigger gap... weaker output. But how much weaker? :huh:

As far as pole pieces:
The 3-phase 550 has 6 magnets producing 12 poles on the rotor (6-north, 6 south, evenly-spaced and alternating). Think of it as 6-pairs of poles. On a 3-phase stator, each phase must have a pole-piece for each pair of poles on the rotor. Therefore, there are 18 pole-pieces on the stator. A pole-piece looks like a coil (or a spoke) on the stator. That means there should be 18 coils on the stator.

On a single-phase stator, there must be 2 pole-pieces for each pair of poles on the rotor. In this case, that would mean a single-phase stator would need 12 pole-pieces (coils) to work with the same rotor.

So, here's what you want to look for: Assuming you are keeping the same rotor, then the number of pole pieces on a 1-phase stator should be 2/3 of the number of pole pieces on the 3-phase stator.

On the 550, it is 12 to 18. (2:3)

Let's say you have a rotor with 5 magnets. Then the 1-phase stator will have 10 pole-pieces and the 3-phase stator will have 15 pole-pieces. (still 2:3)

If your 1-phase and 3-phase stators don't have a 2:3 ratio on pole pieces, then that means they were meant for rotors with different numbers of magnets and are not compatible.

Post edited by: loudhvx, at: 2005/10/27 00:37