Britbike forum
Posted By: Bola Can a stator be repaired... - 01/09/16 9:05 pm
... when the wires coming from the unit have broken off. The wires were extremely brittle when dismantling the primary. They simply broke at the attachment point. Is there a way to solder new wires successfully? One wire is almost burried in the resin. It looks questionable. mad

[Linked Image]
Posted By: Magnetoman Re: Can a stator be repaired... - 01/09/16 9:26 pm
Originally Posted by Bola
Is there a way to solder new wires successfully?
Yes, but it won't be easy, and there's no guarantee of success.

If you excavate straight in you will hit the ends of the wires without hitting the neighboring coils. You can even enlarge the diameter of the hole enough to give you some working room without much risk of hitting a coil. But, you then will be faced with the task of making a half-dozen solder joints without allowing any of the wires to make contact with any of the others.

If the individual wires were to be placed side-by-side and soldered that would double the area of the overall bundle (plus some, because you'll have to insulate them as well). If placed end-to-end and a butt joint made (which won't be strong) it still would increase the area but probably by less.

Again, it might be possible for you to do this, but it won't be easy.

p.s. since it is possible in principle, and since it's worthless as-is, you have nothing to lose by trying to repair it.
Posted By: LarryLebel Re: Can a stator be repaired... - 01/09/16 9:32 pm
I have a spare 16amp (supposedly) stator you can have for CA$100.
Posted By: gavin eisler Re: Can a stator be repaired... - 01/09/16 10:02 pm
That stator is Finished with a capital F, the blooming epoxy and the cooked wires . I can almost smell the cooked resin. Dont even bother , look at the damage all round , put it on the Dark Mass shelf and move on.
Posted By: BSA_WM20 Re: Can a stator be repaired... - 01/09/16 10:19 pm
Yes it can be repaired.
There is a lot more wire inside the stator to solder on to.
However you have to be really careful becuse it is very easy to take the varnish off the windings and short them out against each other.
In fact you can strip all the potting mix off. remove all the wires, rewind it then redo the encapsulation not a particularly difficult job, just painfully slow and if you try to rush it you will stuff it up.

OTOH they are readily available so why go through hours of tedious work when you can get brand new, NOS & aftermarke replacements readily
Posted By: gavin eisler Re: Can a stator be repaired... - 01/09/16 10:39 pm
In a worst case scenario , I might consider repairing this stator, zombie apocalypse , only way out, no comms.
Posted By: quinten Re: Can a stator be repaired... - 01/09/16 10:56 pm

The wires go straight though the laminated hole
and are soldered underneath the encapsulation
(on the side opposite from which they enter )

There is a good write up of the process in your "Rupert's ratio" for unit singles .

Use silicon wire .

Is its worth doing ?
Yes , if you have the time and tempment
.... A maybe worth trying even if you scew it up
Fix the stator and buy a new rotor .

.
Posted By: gavin eisler Re: Can a stator be repaired... - 01/09/16 11:06 pm
maybe if nicola tesla is in your gene pool this may be worth some time, otherwise it is " A senseless waste of human effort".
Posted By: Bola Re: Can a stator be repaired... - 01/09/16 11:25 pm
Originally Posted by gavin eisler
" A senseless waste of human effort".


Sounds like this is the consensus. Into the bin it goes. Thanks all for the input.
Posted By: BSA_WM20 Re: Can a stator be repaired... - 01/10/16 6:28 am
Heavens no.
It goes in the box of "repairable is desperate" parts or along to the next swap meet / auto jumble.
Some one will want it if the price is right.

Like magneto armatures and fiel coils it can be repaired, just not economic for the avarage Joe.

I am seriously looking at removing igniton modules from a pile of mower magneto coils as some of them are well over $ 100 and a timing module is only $ 12 ( trade price)
Posted By: Ger B Re: Can a stator be repaired... - 01/10/16 7:29 am
Quote
Is there a way to solder new wires successfully?

If the coil assembly has been as hot as it looks, there may be an internal short circuit in the intestines of the coil.
Soldering new wires onto the coil in that case, will not solve the problem. 2c
Posted By: kommando Re: Can a stator be repaired... - 01/10/16 7:32 am
It looks cooked, if it was just the wires broken then repair but any heat damage means its not worth the bother.
Posted By: Mike Stillwell Re: Can a stator be repaired... - 01/12/16 9:37 am
Does anyone know the correct resistance for the stator? I'd like to check mine before I put it together.
Posted By: John Healy Re: Can a stator be repaired... - 01/12/16 9:53 am
If we only new which stator you have...
Posted By: gavin eisler Re: Can a stator be repaired... - 01/12/16 11:30 am
The old stator isnt total scrap, the core could be used after cutting off all the old coils, it could be cut down to a 2 bolt 4 coil ignition only unit ( or left complete), it would need new coils and some winding skills but it may be useful to someone.

stock type stator the resistance through the coils is close to 0, maybe 0.5 ohms. ET stators have some coils with finer windings which give more resistance. First check all coils are free of earth leakage, coil to core should be very high ( infinity ) ohms

This test will not find internally shorted coils, but gives a rough guide to condition.
Posted By: Mike Stillwell Re: Can a stator be repaired... - 01/12/16 1:05 pm
HAHAHA OUCH smile
It's a 1969 A65 Firebird, there seems to be only 2 wires coming from it.
Posted By: Mike Stillwell Re: Can a stator be repaired... - 01/12/16 1:06 pm
Thank you Gavin
Posted By: shel Re: Can a stator be repaired... - 01/12/16 7:15 pm
If it were mine I wouldn't try and repair it, in my mind I would always believe at some point it is going to fail and just how far from home am I gonna be when it does, and I'm the sort who tries to repair before replacing something.
Posted By: DavidP Re: Can a stator be repaired... - 01/12/16 9:55 pm
Good time to find a 3-phase stator. They use the same rotor.
Glad I did, no worries about charging.
Posted By: DMadigan Re: Can a stator be repaired... - 01/13/16 12:37 am
My two wire stator is 0.4 Ohm. Acetone should dissolve the epoxy, I am not sure about the shellac on the wire. You can check solvent compatibility charts for that. Worst case you have a frame to wind new coils on. Match the wire gauge and number of turns. People rewind electric hobby motors all the time so look on one of those sites for styles of rewind.
Most Lucas stators that I have seen look like that with bubbles around the edges. The other side should be relatively smooth as it would have been the side in the mold.
It is possible to mount a generator off a more modern bike if you can do some machining. Single phase go for a GS650 ND or Kokusan. The rotor mounts open side out and the stator mounts to the primary cover. Newer than that an '01 Suzuki 750 or 600. Not too modern as they went to more LED lighting and efficient ignitions. New stators are relatively cheap on Ebay, rotors best to get used.
Posted By: Zombie Re: Can a stator be repaired... - 01/13/16 7:31 am
I 100% agree w/ the new stator crowd BUT, I run HPI programmable ignitions in everything I can adapt them to. They all come with separate "charging coils", and honestly, they suck (the charging coils).

So I have to rewind every one of them. My numbers for wire gauge, and turns will not help here but the fact is when I use a smaller gauge than the factory, and more turns, I get a stronger output.

Their base coil puts out approx 12.5v/ 5 amps rectified. My re-wound coil put out around 14v/ 8 amps, rectified. These are basic charging coils meant for race/off road only but I adapt them for street running LED's.

If you have time and patience, it's a fun project. Generally speaking, 03AWG sizes smaller, and 1/3rd more winds will up your output, and be just as reliable as any other stator.

Dissolving the old epoxy is a waste of time. I've never found anything good at it. Just cut it/ and the old wire off. You can guesstimate the amount of wire/turns by the weight of the cut off wire.
Going 03 steps smaller, and weighing as you go you will know when you have the right numbers.
In YOUR case with the same size wire, the weight will be the same, and thus the turns/output will be the same.

As pointed out, there are lots of hobby sites that have the exact formulas. Your new stator can be mocked up in a drill press or lathe or even in a vice with the rotor in a hand drill to see before hand where you are anyway.
Posted By: Elijah Re: Can a stator be repaired... - 01/13/16 8:55 am
I owned a 350 Honda twin many years ago & one winding of the stator burned out.
New part would have cost more than I paid for the bike !!
My late uncle , Frank Wood (Radio ham ZS5FW)said " whip it off , I will fix it "
Quick as a flash I handed it to him. No encapsulation.
He measured the gauge , counted the turns as he stripped it , wound it by hand & varnished it with real shellac after soldering etc.
2 or 3 cam chains later the charging was still fine.
2 or 3 ripped carb slide diaphragms later charging was still good.
10 " crack in the rear fender & disintegrated tool box , still charging.
Mercifully a car T boned me one night & wrote the bike off (I was OK )
Was paid out by the driver for the worst bike I have ever owned !!!!
Posted By: Mark Parker Re: Can a stator be repaired... - 01/17/16 8:42 am
I have a 3phase that was at least as bad as that and I just dug down to wires I could solder onto then used a resin filler to re-encapsulated the soldered wires and its been perfect for the last ten years or more. The actual windings in that one in the photo are probably fine. There is a product that is like a paint on insulation after its soldered, or you could use heat shrink before re-sealing with resin. Resin holds the wires so the brittle section and the soldered joins do not move, only the fresh new wire you attach.

As has been said before it's no good as is and is worth an attempt.
© Britbike forum