Stator problems

[amiklic1]

I built a new stator for my next 4 foot wind generator. It came off pretty good, and I was proud of the good resin work. Until today. It's based on H. Piggot's design alternator, but it's changed so the stator and the magnets are behind the blades.

I saw the problem while OC testing.

It's three phase, 8 magnets and 6 coils (as usual).

I tried to turn the rotor by hand, keeping somewhat similar rotational speed.

Results:

AC Voltage between phases 1 and 2 = 5 Volts

AC Voltage between phases 1 and 3 = 5 Volts

AC Voltage between phases 2 and 3 = 0.2 Volts

If the problem is in the 3rd phase, why is it working good in a pair with 1st phase?

If the problem s in the 2nd phase, why is it working good with 1st phase?

Or, maybe two phases are wrong.

Also, when I tried to short-circuit the wires, I got the same result. When wires 2 and 3 are connected, rotor keeps turning. All other combinations (1+2 and 1+3) stopped it.

When measuring the resistance, I got the same results measuring between any two phases. That's what's confusing me so much.

I suspect that two phases are bad (2nd and 3rd). And I just don't know what's wrong? I was very careful, working step-by step, excellent soldering....

[Titantornado]

Sounds to me, like it's a flipped coil in the bad phase.  If so, it's toast for use as a three phase unit.  Probably using the two remaining phases will cause  excessive vibrations.  Hmmmm, sounds like a loss.

[Flux]

I think it is a flipped phase. The 2 coils are connected correctly but the start and finish of a phase are crossed.

If you know where the star point is, carefully dig into that point and break the star point to the dead phase. You can cross that phase externally, not so pretty but you can save it.

good luck.  Flux

[Flux]

No that's too simple, I agree with you that this is a bigger mess.

I am beginning to think that you have done something with 2 series connections between coils and possibly joined coils that are not diametrically opposite.

You may not be able to fix it without excavating all the interconnections. Try to get to the star point and see if all three phases are equal. That may give you a better idea of where it is wrong.

[Flux]

I have a feeling that you have done this. May give you some idea where to look.

If you can get the star point and feed a current into each phase with a battery and limit resistor then you can explore with a magnet and find which coils are energised in each phase and zoom in on the crossed connections.

[amiklic1]

I was thinking of taking all the wires outside the stator, and to glue the junction box on the back side of the stator with epoxy. That would allow me to make interconnections as I wish, but at the end of a work I was a bit hurry. Now, I guess I'll pay for it. Anyway, i'll dig the star point and try to see what happened. int here. Thank you!