DELTA wiring a mini windmill how ?

[fuse]

Hello,

I´m working on a mini windmill as "side" project it has 6 coils in the flat pancake stator and 16 magnets, 8 in each spin wheel surrounding the stator. Coils is 0.3 mm (Metric system) ( 0.04 inch ) copper wire, 3500 wrap, Magents are 1.2 inch long 0.5 inch thick.

Bellow is a wiring diagram of "Delta" configuration that I maid in photoshop, I hoped it would work to produce some "amps" but at 400 rpm it only produced 0.07 amps :-( and 50 volt.



If some kind soul could point me to if the wiring is wrong and how do I adjust it to be a correct Delta wiring.

Best Regards

Fuse

[JW]

The first thing I see wrong is the rectifier wiring



Try wiring like this and see what happens with your test

[JW]

[mab]

If I've followed your diagram right it looks like you've reversed the yellow phase to me. But rectifying individually like jw suggests would solve the problem  anyway.

[JW]

Ive never seen this rectifier before but it exists

https://www.mouser.com/ProductDetail/Vishay/VS-36MT160/?qs=CDqwynd4ZNofBWqT03A8LQ%3D%3D&gclid=EAIaIQobChMI1qDiiYHH2gIVkITICh0UoQZKEAQYASABEgJ6KvD_BwE

[Bruce S]

I have the 3-phase rectifiers. They work pretty well.
For someone just starting out, I am in favor of using separate rectifiers.
This helps in troubleshooting .

fuse:
If your notes are correct, 1/2 your coils are revered,  It could be just the photoshop though.
 
IF you have the rectifiers handy, try using 3 separate ones spin the mags and read each sets voltage, see where it's going. IF you have 3 cheapo voltmeters this will be easier to do.
My guess is your copper is setup for higher voltage , lower current. You state this is 3mm which is 9ga wire here in the US, and 3500 wraps?

Could you clarify this for us? That's quite a wrap you have there if it indeed it's 9ga wire, it's it's actually 0.04inch wire, that makes it 18ga wire and and a 3500 turn (wrap) would be easier. Especially for a beginner.

Cheers
Bruce S

[SparWeb]

I'm pretty sure Fuse wrote 0.3mm diameter wire, meaning #28 gauge.  But that is 0.013inches diameter, not 0.04in, not what the OP wrote, so it would help if the OP fuse could clarify.
The OP also says they used 3500 wraps, which is a lot.
Assuming the wraps start with a 1" diameter on the inside, then the resistance per coil is about 100 ohms.  Two coils per phase is 200 ohms, connected in Delta gives 133 Ohms per line.
That would account for 50V at the rectifier but < 1Amp.
When you do re-wire, according to the advice above, be careful with the high voltages this generates!

[Ungrounded Lightning Rod]

If I've followed your diagram right it looks like you've reversed the yellow phase to me.

Correct. Swap the end of the yellow winding (or the ins/outs of the individual coils) and you have a delta.  With one phase reversed you have a short between a pair of windings totalling to a particular phase and a single winding with the same phase but reversed.  Lots of circulating current, but no appreciable voltage - just the errors from exact cancellation.

But rectifying individually like jw suggests would solve the problem  anyway.

Per-phase rectification gives you the same voltage and current as delta, without the losses from the circulating current from the 3rd, 6th, 9th, etc. harmonics - which DON'T cancel out around the delta and thus are shorted and drop their (hopefully small - much lower than the extra resistive losses of an equivalent Y) contribution of the generated power into heating the coils.

But it also means more rectifiers.  More cost, more points of failure.

And you REALLY only want to electric-brake the windmill by shorting the coils UPstream of the rectifiers.  Upstream you just short the AC lines and you get braking - with the rectifiers blocking any current from the battery back into the genny coils.  Shorting it downstream (even if you DID disconnect the rectifiers from the batteries - at which point the mill was unloaded and started running away, boosting voltage and storing energy as momentum) can lead to massive current spikes and the destruction of the rectifiers.  And THAT leads to a tower climb to repair them (since you no doubt mounted them on the genny so you'd only have two, not six or three, drop wires.)

[Adriaan Kragten]

The disadvantage of rectification in delta is that the unloaded torque rises faster than for rectification is star because higher harmonic currents can circulate in the winding. The advantage is that the maximum breaking torque in delta is higher than in star (see my report KD 78). PM-generators are mostly rectified in star to prevent higher harmonic currents. But if you use the generator as a brake, you get the maximum breaking torque if the star point is short-circuited too.