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Tinker Guru Joined: 07/11/2007 Location: AustraliaPosts: 1904
Posted: 01:16pm 08 Nov 2007
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While reintroducing myself to the secrets of three phase alternators - a rather too long time had passed since I had got formal training in that subject - I came across this article:
http://www.windstuffnow.com/main/3_phase_basics.htm
which explains it nicely.
Now, while cutting all the wire links in my F&P stator to prepare it for 7 phases I noticed that ALL coils were connected the same way round.
The above article says that 3 phase alternator coils are all wound in the same direction but the coil group of phase two is reversed, eg. start and finish of coil is reverse connected.
Why is the F&P stator not adhering to that idea? My stator has the 0.6mm winding wire, BTW.
Further, since the 7 phase idea is completely new to me, how would one follow the 3 phase coil connection system as mentioned in the article when 7 phases are involved?
Is there something I'm missing with the F&P stator that gets around this requirement? Its all a bit confusing at the moment but I'm sure there are experts here that can put me straight in a jiffy.
I do prefer to understant exactly what I'm doing when I reconfigure the coils for 7phase 2 pole, there is enough work involved to make it pay its done right first time
Thanks,
KlausKlaus
Gill Senior Member Joined: 11/11/2006 Location: AustraliaPosts: 669
Posted: 03:48am 09 Nov 2007
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G'day Tinker,
Yes, his statement about reversing the second coil is correct because he did state it was for a single phase example. This, his first example used equal magnets and coils too. Whilst unequal magnets to coils and more phases complicate and change that arrangement, the overriding principal that governs the all this is that a magnetic field passing through a coiled conductor will cause a current to flow in a fixed direction.
This basic principal holds true no matter what the coil,magnet phase numbers are. Sadly the other site you refer to does not use this as the basis of it's explanation hence bridging his theory, whilst correct, to other arrangements is difficult.
For your 7 phase F&P, follow the examples of this site explicitly and you will not have a dud. As for understanding, I would not try to explain the F&P 7 phase his way, it is much to much on this forum to even explain it my way. No doubt your enquiring mind will seek this out in time, though I suggest you try grasping the standard factory F&P 3 phase first before looking at modifications.
I think you are like me, there is less enjoyment when there is less understanding and more enjoyment when then there is new understanding.
Best wishes on your project. Edited by Gill 2007-11-10was working fine... til the smoke got out.
Cheers Gill _Cairns, FNQ