Maximizing wind turbine for use with MidNite Classic 150

[Watt]

I'm building a turbine with 40 2"x1"x1/2" n42 magnets in a 20 pole 15 coil 3 phase configuration.  I've built the rotors with 1.375" spacings between the lower closest points of the magnets due to the 14 awg coils and required turns for around 50v dc cut in at 100 rpm.  48v battery bank.

My question is, should I build a more stiff alternator with more copper or should I stick with the traditional otherpower specs with the classic 150?

This is the second set of rotors I have built but, I would be happy to build another set if required.  I have not built a stator, only coiled wire and proceeded with math for cutin.  I'd like to get the best use out of all materials I have as this will be the last turbine I will build for some time. 

Thanks
Mike

[Robin]

Ryan's standard OtherPower coils seem to work quite well. I don't know about a different winding ratio. Try calling Dan and Dan at OtherPower.

[Watt]

Thank you for your reply.  I have a thread on fieldlines.com regarding this question with no response.  No biggy, I've been experimenting.  I'll post progress. 

[keyturbocars]

I am not familiar with the axial turbines myself, but Ryan from Midnite has worked with them before.  He might also have some comments about this. 

The Midnite Classic is definitely the way to go with a wind turbine.  I am very happy with my Classic 150 controlling my HY-2000 2kW (has put out over 4kW) wind turbine.

Edward

[Halfcrazy]

The traditional Otherpower style Alternator is pretty darn stiff. I have tried shorting just 2 phases of a few I have been involved in and they just stop even in 80+ MPH wind. I see no reason to really wander away from the standard design. One could wind it for say 60 volts cut in and maybe get a little more power in the 6MPH range but there is very little power there to begin with so it is not a big deal.

I have been awful happy with my 10ft machines performance on the Classic as well as the 17 foot My neighbor John and I built for his place. We followed Otherpower's plans on the 17ft machine and with there blades had seen 9kw once or twice. That was a little much but after our clearance issues with one blade and the tower we went to a set of the Royal wind and sun blades at 16ft diameter and made w few changes now it furls to early 3-4KW is about its limit. I have found Otherpower's blade profile to be much more forgiving of TSR than the blade design from Royal wind and sun so maybe I just need to keep tinkering with the power curve when we start getting fall winds. I would really like to see about 6-7kw peek on this machine.

As far as magnet spacing my understanding is in a perfect world you would build the coils with a hole in the center the magnet would fit into if that makes sense? Than you would space the magnets so the coils did not quite touch each other. Now all the turbines I have been involved with we made the coil wider at the top and kept the coils closer together to make the spacing of the magnets closer keeping the diameter of the rotors smaller. I have talked to Dan about this and he feels the losses are so small it is not worth the extra steel etc to make the rotors larger. If I was starting from scratch I would be tempted to try spacing them out a little more.

[Watt]

Thank you both for the replies and congrats to your success with the classic.  I should have added a bit more information and constraints.  I am try to use some of what I have left from other projects.  I have 14 awg and 16 awg wire left with 14 awg being the biggest quantity at around 30 pounds.  Using the coil winder from my 10 footer and using the 14 awg wire, I'm about 1.375" spacing at the narrowest point.  I am afraid the extra copper is going to make the alternator stiffer than normal and I'm not sure what the classic characteristics would be regarding this possible stiff alternator.  I've also thought about the RWS blades at about 14.5' diameter to help keep the voltage down with tsr.