Muffin Fan, how to open, pics

[nothing to lose]

Ok someone wanted a Muffin Fan opened for some reason and said they always ruined them trying. I also had a bit of trouble opening them and give up before I trash one.

Here is the one I just opened, no harm done

Peel off the label on the back side hub area. There is a little rubber cap/plug in the center. Pick it out with a pointy object like a needle or pin. Under the plug then is the shaft, it is held in with a tiny little C clip. Get that poped off the shaft and just pull blade off front.

As you can see in the pic, it has 4 tiny windings in the center, a circuit board under that. The shaft is stuck in the fan pretty good. The magnet is rather odd. Apears to be a full circle band, sort of rubber like a flexible fridge magnet. Pressed or glued in the fans hub, I have not tried to get that out. You can see the little plug in the pic sitting there also.

 Heck, this fan cost me a hole $1 you don't think I'm going to totally tear it up

 Actually this Top motor fan is a 80MM computer fan with sleeve bushing instead of ball bearing, and I bought a few at a time. Most likely cost me 75cents or so.

I was playing with this fan and batteries last night. 12V fan and it work really nice at almost any battery volts up to around 18v. But when I connected it to a 24V charger for a cordless tool (27.9VDC I think) it ran pretty fast for a bit then slowed down.

 Of course I was burning it out. Well it now (or did) run slowly at 12V. Funny thing is I was checking milliamps with a good one also. New fan about 0.19ma to start and 0.15ma to run. There was a "pasive solar heater with solar fan" post also and the question of startup amps popped up. His fan would not start on his pannel.

 So for this 12V 80mm muffin fan we now know 0.19ma at 12Vdc for starting.

This half burned out slow fan was drawing double the run speed milliamps, 0.31ma. less than half speed.

Anyway, I stick this in wind power I geuss because I think who-ever it was trying to get one apart before had wind in mind. Maybe using the blades for a mini mill or something. I had that thought once also

 Perhaps Ghurd can take a few apart and use the blades on steppers

See if they have any wind use that way.

The rubber magnet band in the blade is pretty weak, makes a ceramic look like a neo :0

 You probably can't tell in the pic but the 4 pole plastic "armature" does have metal center to pull flux. It spans the length of the white plastic holding the coils, my geuss of course is that it goes to the center through the coils also, but I did not take it apart that far. It would makes sense, but then I did not actaully see it to be certain.

So how would I re-wind this to get 12V 10 watts at 20mph??  Ha HA

[nothing to lose]

OH, and no I did not get a camera finally, that pic is from the scanner.

[dinges]

Never knew how one looked on the inside; did give it a spin once, a few years ago, to see if any volts came about, but nothing that could be measured came out of it.

BTW, I think that you mean 0.19A instead of mA? most I have are a bit over 100mA. Just one letter difference on paper, but a factor of 1000 in reality :-)

Can't imagine that even a small solar panel couldn't start up one of these guys; mine can (17V/150mA output) (tried after reading about it in the other thread).

Peter,

The Netherlands.

[nothing to lose]

I think your probably correct, I used the 20m setting on the digital meter for amps readings. 0.19 amps, the setting I used was just that I could only read as high as 20m without going to the next higher setting. Duh on me,

Thanks for correcting me on that.

I thought something was odd the way I wrote that after I posted it. Was not sure what though.

Now as far as spinning one and not geting anything, I think that could be the circuit in the fan, I also could not run this one backwards by reversing the leads. I'll probably play with it again later, but now I got time to leave and work on other things, I don't have to just sit here right now like I do alot of times.

Later I may try to remove the board and see if it makes any power when spun. Not sure at this time how that comes apart.

[Nando]

I have used the higher voltage (24 & 48 volts) ball bearing fan muffins for small power generation.

I opened them and placed small Schotky diodes to the output leads ( 6 each -- 2 per phase) and carefully made sure that the pulsing circuit was disconnected.

Most of the magnets are plastic type with low flux energy but just enough for some very limited use that may require higher RPM for some power generation

One has been working for the last few years feeding batteries for a remote NON-snow area RF connected Anemometer and other specialized data -- producing 2 watts @ 12 volts (up to about 20 volts with a MPPT charger) and using centripetal force Pitch control to limit the RPM to about 2800- 3400.

The system has as well a 1 Watt Solar Panel.

Using a CMOS microprocessor that stored data and at the right moment, considering battery charge, sending the data with acknowledge and reporting the wind mill and the solar panel power capabilities.

Nando

[willib]

Nando , interesting post..

That fan has a Hall Switch in there , which outputs a voltage which flips twice every rotation , although i have seen some that swing from +12 to ground four times a rotation..

I have used one as a Anemometer , you have to take out the coils ,but leave the circuit board intact, when you do this it spins freely ..

oh , If you Power it with 5V the hall switch  will swing from 0 to +5 V , nice voltage for digital counting..

[nothing to lose]

Well I broke mine now.

It appeared that the circuit board was glued in and while trying to pop it out The rear center hole of the case broke out. Will have to look at this more closely. It looks like the white plastic legs are soldered to the back of the circuit board? Lead solder on plastic?  I was figuring probably some type of clip end poped through a hole, but does not look that way now that it is out.

Now that its out, hard to see, but it looks like the case has a raised center shaft instead of a hole. The board, coils, etc.. pushed down over the center shaft, maybe glued? Then the bushing is in the center of that shaft, and the fan shaft goes through the bushing and locks in place at the rear with the C clip.

Well at least we can get the fans off without breaking them, that's what I was mostly wanting anyway myself. Now  to get the axle shaft out of the fan without breaking anything. Vice not handy.