Questions on axil generator

[Tall Paul Man]

Hi all,

I would like to build a small axil generator with about a 4 in diameter from scratch using a 3 phase design with a output in the 30v-40v range. Can anyone give me a starting point as to what gauge magnet wire to use?

Also does anyone know of a software utility for designing generators?

Thanks! Travis

[gww]

travis
Do you mean 4 inch diameter?
gww

[Frank S]

if you are thinking 4 inch diameter then you could possibly have 7 1 inch diameter magnets on the rotor with 6 coils
 or possibly 8 1/2" by 1 1/4" magnets with 9 coils
 I'm thinking 2 or 3 in hand 22 ga wire not sure how many turns because a unit that small could spin 2000+ PRM with 1 1.2 ft blades 3 ft diameter. but  I doubt much more than 30 watts if that much
 but there are plenty of guys on here who have built them and can tell you almost to the exact inch of how much copper you would need and predict your output at any given wind speed.

[sean_ork]

7 magnets ?

nsnsnsn .............

[Frank S]

Yea I thought of that too I should have said 8 or 6
 but I do remember someone once on another forum that  aligned all of his magnets nnnnnnn double sided the rotor with the sssssss on the opposite  used 6 coils on each side but alternated left hand right hand lay it was a weird way  of doing it but he said it made some power

[tecker]

I've been working on some Gensets in the 5 " rotor size and the flux penetration is a key part of the design . the coil needs to be thin and flat to get good penetration and the gap as small as possible . 

[GoVertical]

Hi, do you have a target RPM range for the PMA?

[Tall Paul Man]

I don't have a target range for the RPM.  Also I probaby be ok with 12 volts. This planned to be part of a portable system that I can attach to an electric beach vehicle. It would charge the vechicles batteries when it was sitting on the beach and continue to charge when the vehicle was in use. Top speed is expect to be in the 3-5 MPH range. I not sure about a 3 foot diameter blade overhead, but I could use a smaller blade?

Travis

[GoVertical]

Hi, small diameter requires a high RPM. Use the largest; strongest; magnets you can find, with a small gauge wire and a lot turns for the coils. The coils will have a high internal resistance. A MPPT controller will convert a high voltage with low current to a lower voltage with higher current and solve the stator resistance problem, if you can find one. Another possible option is to stack the stators and rotors, but the weight becomes a problem. Are you planning on a HAWT or a VAWT ?  I hope to see photos of your project.




link to calculate coils : 

http://www.6pie.com/faradayslaw.php

[Tall Paul Man]

I have considered both HAWT or a VAWT. The VAWT makes it easier to hook into the drive train thus possible having a direct drive system and bypassing the battery and electronics all together. But the lower efficiency makes the HAWT more attractive, but the VAWT might be a potentally safer design. Its a complicated question, but leaning more towards a smaller HAWT.

Travis

[fabricator]

What do you plan to do with this turbine?