New Alternator Idea

[taylorp035]

I am sorry, the cell# means the number of nimh AA cells being charged in series.  They are 2.5 ah and roughly 1.3 nominal voltage.

Here are some more numbers...

no load voltage

3000. rpm = 11.41 volts
      
650. rpm = 1.89 volts
     
540. rpm = 1.34 volts, which would be my minimum cut in speed for a one cell set up.
     
     

Here are the amps and watts for 3000 rpm

1. cell = 3.59 amps - 4.667 watts
   
2. cells = 2.63 amps - 6.838 watts
   
3. cells = 2.33 amps - 9.064 watts
   
4. cells = 1.96 amps - 10.153 watts  - most efficient
   
5. cells = 1.49 amps - 9.66 watts
   
6. cells = 1.04 amps - 8.102 watts
   
7. cells = 0.57 amps - 5.18 watts
   
8. cells = 0.21 amps - 2.18 watts
   
   

based on today's findings, here are the approximate cut in speeds

1. cell - 540 rpm
   
2. cells - 800 rpm
   
3. cells - 1200 rpm
   
4. cells - 1600 rpm
   
8. cells - 2900 rpm
   
   

After all of these 30 some odd posts, I have finally concluded to make a 6:1 gearbox, use my old 5 foot blades and my new 3 phase brushless tape drive motor.  The cell number will vary depending on wind conditions.  I am hoping pull out over 50 watts out of the tiny motor.  I have put at least 300 watts into the motor before.  I have another motor that is the same, but I rewound it with 16 gauge and put of 60 amps into it.  It spun so fast that I thought it was going to explode!

I will try to get a picture of these motors up on here sometime in the next couple of days.

[taylorp035]

You make an interesting point about the efficiency...

My 30" hit 20 watts in roughly 25mph winds.  The wind was not extreme.

Power = 1/2 * radius^2 (in meters)  * velocity^3 (in m/s) * efficiency

20 = 1/2 *   (.762)^2               *    12^3   *   ?

efficiency = 4 percent at 12 m/s

           = 6.9 percent at 10 m/s

Hmm...  That's not very good for a PM windmill, but certainly my personal best and not too bad since the motor does not have neo magnets.

[taylorp035]

Opps..  

The radius should be half that number.

Then that comes to  16 percent at 12 m/s   and     27.6  percent at 10 m/s

[taylorp035]

here is the motor for all of the data

[ghurd]

The best output, in a usable form, that I managed to get out of those, is leaving them wired Wye, then feeding it into the low sides of 110:6 wall-warts wired for 3 phase.

G-

[Turfdr]

Here is a rotor I finished last night.





It's a Delco out of 1986 Camaro, not sure what series it is but I think it's 100 amp.

I cut the shaft and replaced it with n52 3"x 1" disc and n45 3" x 1/8" disc to get the get the same width as the factory core.

Then I glued it all together with JB weld.You probably need the jaws of life to separate these but the glue keeps the two rotor halves from twisting.

It was not easy to make but it only cost about $60 in magnets and is one powerful rotor.

I made one out of a 10dn a while back and it peaked out at about 130 watts with 5' rotor and 6 high speed blades and guessing 25- 30 mph wind gust.

And I think I wound one of the phases bad because it didn't put out like the other 2.

Whith the factory stator, cut in speed was around 500 rpm but I wanted it lower.

As you can see the one stator is much smaller.

I plan on making a second machine with factory stators and connecting the rectifiers in series to hopefully get a decent cut in speed.

So I agree, get rid of the factory set up and go with a good powerful ring or disc magnet.

Its a little work and you need some tools but it will put out some useable power.

[taylorp035]

I just finished my gear box for the mini motor shown several posts before.

The gear ratio is 82 to 14, or about 5.82:1

I'm not sure what the rpm was, but the voltage got to at least 18.7 volts.

450 rpm at the input now supplies 4.6 volts, which is high enough to charge at least 3 nicd 1.2v cells.  The shaft is relatively easy to turn, so I don't predict there being any start up issues with my 5 ft blades.

My ESTIMATED max output is probably going to be 25 watts at 1000 rpm for the input shaft.

On sunday, I will take apart my 30" for the nice rotating base and tail and install some go-kart bearings and the blades.

[hiker]

heres one i built awhile back...

made from two alts..

i used the front half of each alt..used both stators[stacked]

rewired with lighter wire-[was only nine coils-later i wave wound]

made a wooden rotor-with metal under each mag.

worked great on my pedgen--lites up 3- 50watt headlites.....all i had at the time..

havent made any blades for it as of yet..