Will these magnets work or too small for axial flux?

[Scott]

I have these neos from a couple 403's.  They measure 3/4" x 1/2" x 1/4".  Are they useful for any kind of small axial flux machine or just too small?

[GoVertical]

Hi, small magnets need high RPM. Have you look at radial flux designs? Try making a test coil. I hope to see some photos of your project.

[SparWeb]

How come the two rotors can be so close together without -

moving further apart, or

crashing into each other?

Seem too close for comfort either way...

[ChrisOlson]

How come the two rotors can be so close together without -

moving further apart, or

crashing into each other?

Spar, if you've ever taken a 403 apart you'd know they're not very powerful.  Those magnets are about the size of chicklets and they're not very dangerous.
--
Chris

[Scott]

Yeah, there not that strong.  Makes me wonder if one of these air units might actually make power if I put larger stronger magnets in it. 

[ChrisOlson]

It won't.  Those little blades only got so much in them and they have to run really fast to make the few watts they do.  If you put bigger magnets in the blades wouldn't run fast enough and you'd get less power.  The Air 403 and Air-X are what they are, and that's not much.  Using one for off-grid residential power is kind of like trying to use a Toyota Prius to pull a semi trailer - it won't work.  As far as I'm concerned they're a device that was invented to convert rotary motion into noise.

I know a guy that has four of them providing a trickle of amps when the wind blows good for his off-grid home.  When you drive into his place you'd swear his house is infested with hornets.
--
Chris

[Rover]

Mine never did that well, think its the way I mounted them on the shed, probably the wrong angle...
Scott, the one on the shed is the 24V we traded






I will say that the bugger managed to survive Hurricane Irene as evidenced above (though the shed didn't) , and managed to hit 28A. Although the total output for the day, with hurricane force winds was ~ 100W

[Scott]

Wow Rover you must of had some wild winds.  Bummer on the shed.

What's the other unit you have on the tower? 

[Rover]

Its a 7' Chines turbine... does ok. ~ 450W


I had it shut down during the storm, the 403, I just let be free....

[ChrisOlson]

I had it shut down during the storm, the 403, I just let be free....

That's the way them 403's like to run and that's the kind of wind they need.  Hurricane Irene was probably good for it and blew the cobwebs out of it.   

That's a bad deal with the shed - looks like it might need some minor repairs.
--
Chris

[Flux]

The 403 is a high speed iron cored alternator with a small air gap.Those magnets will be useless for anything with a significant air gap. That rules out any form of dual rotor machine. They are also magnetised to suit a radial flux alternator and would be near useless for a dual rotor axial.

That doesn't mean that you couldn't get so,mething out of them but it would never be worth the effort except for a fun machine with a small fast set of blades. Even the 403 blades would only give a few 10s of Watts with an air gap alternator.

Flux

[Scott]

Kind of figured as much Flux but thought I'd ask.

[Warrior]

This is an Air X´s 24 volt power curve:



I don't think the alternators are useless. I once modeled this alternator with a 2 m geared turbine and it actually modeled OK.

I can't think of any direct drive application but maybe with slightly larger blades and rectifying each phase and putting them in series you might get some power at lower rpms...

Warrior

[Rover]

Warrior,

I've tried Air-X's , now this 24 volt 403 (modified IRP for 12V, down tower, switchable star (original config)) ... I've data logged for months.

Honestly if you don't own a boat... not worth it ...  (on a boat you have usually clear wind )

They tend to hit cut in and stall immediately afterwards unless its in a consistent non turbulent wind.




 

[Flux]

Warrior, you are right that the alternator is not useless but it only works in a high wind region, with gearing and bigger blades it could work in lower winds.

The question was about using the magnets in an air gap type alternator and in that case it would be about useless, it was designed for an iron core and there is not enough flux per pole with a big air gap. You would need even more gearing to overcome the very thin wire and high resistance that an air gap machine would need.

Flux

[jlt]

     I think That you could use them in a 4 pole induction motor. use 6 mags of the same polarity on each pole.

[electrondady1]

it looks as though the faces of the mags are covered with a metal band.
perhaps that is to help retain there position at high rpm?

if they were mine, i would use all the mags to form a single rotor radial with twice the poles of the original alternators .
form a centre rotor of wound steel wire and place the coils on the surface.
place the magnets on the inside of a round rotor (steel pipe of appropriate dia.)
i think i would go for a two phase layout with overlapping coils
use some gears to spin the heck out of it.

every good magnet deserves to live in an alternator.

[esc]

Scott,
I sent you a PM. 
I just remembered that I have about thirty 3/4" round x 1/4" thick N42's if you are interested in a trade.

Eric

[Rover]

You could always connect the two generator heads together on shaft ... parallel after rectifiers

Course then you just end up with a 2x 0 power ...

[esc]

Scott,

After reading your other thread I am sure that (as everyone else has already said) these magnets are not what you need.  I think that your best bet would be to sell me your 403 parts and use the money to buy some REAL magnets.

I know some here have a rather poor opinion of the 403 but my experience is that it is a solid and reliable piece of equipment.  It will NEVER make 400 watts, but in a good wind location like you have described in your other thread I would expect it to reliably make 100 watts.  That would be in line with my experience on the beach.

I know this belongs on your other topic, but...
If you are out to fool around, experiment, learn a few things the hard way and/or spend a lot of time figuring out a good combination.  Then start from scratch and make your own design.  I've done it and it was a lot of fun, but it was not a very efficient use of my time. 

If you are serious about making power and don't want to fool around with a bunch of experimentation.  I recommend that you follow one of the well tested recipes that can be found around here.


Eric

[Tritium]

As far as I'm concerned they're a device that was invented to convert rotary motion into noise.
Chris

In addition to taking advantage of "Green Fever" to remove dollars from unsuspecting consumers who happily buy without researching a subject.

Thurmond