rotor / stator design

[Pecanguy]

I hope I am in the correct section to ask this question.  I am new to wind turbine projects.  I am not an engineer but I work with my hands and want to build an axial flow 8 or 9 ft wind turbine and see it work.  I have read many articles and forums on the subject but am confused on the variations in design.  After looking at several designs, they all seem to be similar in construction.  I have viewed the following rotor/stator specs;

Scoraig plans 2002 / Hugh Piggott 2003
12 magnets / 10 coils - 5 phase ac connected in a star configuration cut-in 12
volts at 170 rpm

8 magnets / 5 coils - 3 phase ac connected in a star configuration

12 magnets / 9 coils - 3 phase ac

ITDG, Hugh Piggott
8 magnets / 6 coils - 3 phase ac connected in star configuration

Can someone with more experience tell me the differences in test performance in these designs. More coils or less coils, 3 phase or 5 phase. Does one style have more or less cogging, more or less stator heat and how does this relate to cut-in wind speed (rpm) and output?
Obviously, more magnets and wire slightly increase the cost.  I would like to take some of the guessing out of the project.
Any help will be appreciated.

[gww]

If you want to take the guessing out of it buy hughs plans.  Then make one of them.  his plan will tell you before you make it what you can exspect and if you make it per the plan that is what you will get.  I made two of his 12 magnet ten coil turbines.  That was his old desine and if you read the stiky on the top of this forum's wind page about "adding line resistance" you will figure out his newer plans are better.  It's roughly $28 bucks to get it right.  Mine are 8' blades.  I believe with eight magnets (one rotor or two?)  That your blades will be smaller and faster. 

Can't go wrong with a good proven plan.
Good luck
gww

[Flux]

As stated all these designs from Hugh will work fine as long as you stick to the plans.

The ITDG plans are for a ferrite magnet alternator and it is intended for about 7ft, the alternator is not big enough for 8 to 9 ft that you mention.

I have not seen the 8 magnet 5 coil design but again I suspect it was for a smaller machine.

The 12 magnet 10 coil and the 12 magnet 9 coil designs will be fine. The 5 phase 10 coil design has a lot of rectifiers and realistically you need to mount the rectifiers up on the machine and run dc to the batteries.

The 9 coil design lets you run ac to the rectifier near the batteries.

You look to be considering 12v and the 12 magnet 9 coil design needs a small number of turns of thick wire for 12v and normally Hugh does a different winding for the 12v machine that again really needs the rectifiers mounted on the machine.

You could modify the 24v 9 coil winding with half the number of turns and more wires in hand but it may be tricky for a beginner.

If you want 8/9ft then follow any of Hugh's plans for that size of machine, don't mix parts, the smaller alternators will not work well with bigger blades.

You can also look at the Othwerpower designs that use 12 magnets and 9 coils but again you will be into a few turns of thick wire for 12v.

There is very little difference in performance or stator heating between all these designs if you choose one suitable for that blade size.

You will only find some using less copper if you start looking at alternators for smaller sizes of blade if you stick with neo. If you start looking at ferrite magnets designs such as the ITDG then they will use a lot more copper but you have cheap magnets. To get the equivalent performance the ferrite alternator will be a lot bigger and heavier and I can't think of any published design for a 9ft machine.

Bottom line, choose Hugh's or Otherpower plans for the size of machine you want and follow them exactly and it will be fine, whether you choose 5 or 3 phase it really doesn't matter. I don't think the 5 phase has any electrical advantage, but the thing is very easy to connect as there are no series coils to get in phase and there is little chance of making mistakes. I believe that was one of the reasons for its choice.

Good luck
Flux

[gww]

Flux

I don't think the 5 phase has any electrical advantage, but the thing is very easy to connect as there are no series coils to get in phase and there is little chance of making mistakes. I believe that was one of the reasons for its choice

Thats why I chose it and the plans were very clear.  The only thing I like better about hughs new plans is how he squares the stator mount.

[Pecanguy]

Thanks Flux,
You have offer a better explanation than any other.  This gives me more insight into some of the differences, although I have many more questions.
Again thanks.