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Easy Auto Part Two
By WXYZCIENCE, Section Mechanical Posted on Wed Jul 4th, 2007 at 10:55:22 PM MST
Neo Test Results

This unit is the second unit with neo magnets installed. Only one of the claws was machined to accept the magnets.

The six neos are placed into the claw in a star pile and glued in place with instant glue. I chose six to start because the thickness was the same as the hub that was machined off.

The second claw was left as an original.

The unit was assembled and the output was tested. At 1900 rpm the output across one phase was 6 volts ac at 10 amps. I am impressed. A full test with three phase into an star restive load was 180 watts. The shaft is still the original, with the threaded end fairly magnetic to a screwdriver. I was reading another thread about stacking magnets, so I am wondering if the addition of 6 more would increase the output any more. Also a nonmagnetic shaft is the next step. Anyway I will have to continue having way too much fun.
Joseph

Easy Auto Part Two | 19 comments (19 topical, 0 editorial)

Re: Nonmagnetic shaft (3.00 / 0) (#1)
by WXYZCIENCE on Wed Jul 4th, 2007 at 11:37:02 PM MST
(User Info)

The nonmagnetic shaft is the answer! Here is a picture of the rotor with the brass and stainless steel shaft.

The increase in power is proof that the steel center shaft was shorting a major amount of the flux. The same test at 1900 rpm I am now getting into the star restive load over 300 watts. The only logical next step is to machine the other claw and add six more neos. I think that will give me a very simple and effective alternator conversion. I will probably do that in the next couple of days and post the results then.
Joseph.

Re: Nonmagnetic shaft (3.00 / 0) (#2)
by willib (willibur at comcast dot net) on Thu Jul 5th, 2007 at 12:16:13 AM MST
(User Info) http://www.njwind.com/webcam.html#

cool news!
i'm eager to know the voltage or current at 300 watts
Carpe Ventum (seize the wind)
[ Parent ]

Re: Nonmagnetic shaft (3.00 / 0) (#3)
by WXYZCIENCE on Thu Jul 5th, 2007 at 12:27:26 AM MST
(User Info)

willib, over 100 watts per phase was the average into a restive load. 10 to 11volts and 10 to 11 amps. The tests were done with a fluke voltmeter and a fluke clamp current meter. All three phases were connected so it looks like it might have some potential. I think a couple more neos will do the trick
Joseph

[ Parent ]

Re: Nonmagnetic shaft (3.00 / 0) (#7)
by Opera House on Thu Jul 5th, 2007 at 04:49:31 AM MST
(User Info)

Why stop there. Stack 3 alternators on a custom long shaft. I have an old book from the 30's and it had a project that welded three car generators together. That should be easy with typical alternator construction.

[ Parent ]

Re: Nonmagnetic shaft (3.00 / 0) (#11)
by RP (russp located-at fidnet (dot) com) on Thu Jul 5th, 2007 at 09:53:20 AM MST
(User Info)

Joseph,

I'm curious if there is a saturation effect in adding more magnets.

It would be interesting if you could repeat the test after partly machining out the second claw and adding 1 layer of Neos and then again after adding both layers to the second claw.

[ Parent ]

Re: Nonmagnetic shaft (3.00 / 0) (#12)
by Flux on Thu Jul 5th, 2007 at 11:20:31 AM MST
(User Info)

There is definitely a point when saturation starts to come into effect. With ceramics it unlikely that you will reach saturation, but the old Elektro alternators achieved similar field levels with ceramic as with the wound field.

With neo it is most likely that quite small magnet length will be sufficient, but the cross sectional area will need to be as big as you can get in. Using magnets better shaped to add the most cross sectional area will probably be better than trying to increase the effective magnet length.

The magnet area will need to be equal to the total area of pole tips to get you near saturation in the stator core.

You may find that as you approach saturation the iron loss and cogging increase rather rapidly and it may be better to use a bit more speed rather than push the iron circuit into saturation.

The only way to check for saturation is to plot open circuit volts against magnet material at constant speed. If you keep the steel shaft you may still be able to get a decent field strength but at a considerable cost in extra magnet.

Keeping the claw rotor will not save much in magnet material and may cost you rather more in iron loss than using small individual magnets as discrete poles as in the AirX.

Flux

[ Parent ]

Re: Easy Auto Part Two (3.00 / 0) (#4)
by Ungrounded Lightning Rod on Thu Jul 5th, 2007 at 12:41:53 AM MST
(User Info)

Have you tried using the stainless/brass shaft with the claws and ring magnets from the previous conversion, so you're doing apples-to-apples comparison on the shaft change?

Re: Easy Auto Part Two (3.00 / 0) (#5)
by hvirtane (hannu_markus_virtanen(at)yahoo(dot)com) on Thu Jul 5th, 2007 at 01:08:47 AM MST
(User Info) http://web.archive.org/web/20050404022706/www.cc.jyu.fi/~hvirtane/cooker/

Very good, indeed.

Have you tried using the stainless/brass shaft with the claws and ring magnets from the previous conversion?

That is a test I wanted to see, too.

- Hannu

Re: Easy Auto Part Two (3.00 / 0) (#6)
by oztules (oztules__at__bigpond.com) on Thu Jul 5th, 2007 at 02:42:40 AM MST
(User Info) http://www.anotherpower.com/gallery/Oztules-toys

Good solid stuff Joe, building towards a good output ... although i'm joining the chorus of voices wondering how the s/steel shaft would be with your microwave magnets. It would be a pretty definative experiment.

More fun to be had yet

....oztules
Flinders Island Australia

Re: Easy Auto Part Two (3.00 / 0) (#9)
by WXYZCIENCE on Thu Jul 5th, 2007 at 09:07:02 AM MST
(User Info)

oztules, just like a river, flowing, slowly moving ever closer to the sea. Summer is here and living is easy. I agree, let me predict 75 watt with the steel shaft. If I use a brass shaft it will be 125 watts. I will try it, maybe machine the original shaft and add a short 3" brass insert through the claws.
Joseph

[ Parent ]

Re: Nonmagnetic Shaft and Ceramics (3.00 / 0) (#13)
by WXYZCIENCE on Thu Jul 5th, 2007 at 10:27:23 PM MST
(User Info)

although i'm joining the chorus of voices wondering how the s/steel shaft would be with your microwave magnets.

I machined a brass shaft for the first unit ( microwave over magnets ) and found very good results.

The load for both units was a star restive load made from nichrome wire 1ohm each.

The first test, 900 rpm with the brass shaft was 84 watts for ceramic. 8 amps 3.5vac
O.C.volts 4.65ac
Second test, 1900 rpm with the brass shaft was 225 watts for ceramics. 13 amps 5.78vac
O.C. volts 8.83ac

The first test, 900 rpm with the brass shaft was 141 watts for neos. 10.2 amps 4.64vac
O.C.volts 7.34ac
Second test, 1900 rpm with the brass shaft was 310 watts fror neos. 15.5 amps 7.1 vac
O.C. volts 13.95ac.

Joseph.

[ Parent ]

Re: Nonmagnetic Shaft and Ceramics (3.00 / 0) (#14)
by oztules (oztules__at__bigpond.com) on Thu Jul 5th, 2007 at 11:04:55 PM MST
(User Info) http://www.anotherpower.com/gallery/Oztules-toys

Joseph,
Excellent work and nothing beats actually doing it. Thanks for your efforts at satisfying us all.

The neo's obviously give the better result, but free magnets on a free alternator is not to shabby either.

Thanks again Joe.

.........oztules
Flinders Island Australia
[ Parent ]

Re: Easy Auto Part Two (3.00 / 0) (#8)
by Nando (nando37-at-tx-dot-rr-dot-com Correct theanti-spam) on Thu Jul 5th, 2007 at 07:04:58 AM MST
(User Info)

Joseph:

Experiments like these, can be done and be understood quite fast if some simple calculations are made with some measurements.

For one to take the coil and count the turns, wire size, then the internal and external diameter of the coil and applying the magnetic formulas to define the maximum magnet flux generated by 12 volts and the maximum current limited by the series resistance in the loop.

Knowing this flux then one can calculate the magnet size to replace, as a minimum, the coil generated level.

Nando

Re: Easy Auto Part Two (3.00 / 0) (#10)
by WXYZCIENCE on Thu Jul 5th, 2007 at 09:15:50 AM MST
(User Info)

Nando, the alternator was free. Six neos around 12$. My time 2 hours. If I have to hire an engineer that will throw my budget out the window. Math to me is like doing taxes, I never get anything out of it. Thanks for the interest and comment.
Joseph

[ Parent ]

Re: Easy Auto Part Two (3.00 / 0) (#15)
by hvirtane (hannu_markus_virtanen(at)yahoo(dot)com) on Fri Jul 6th, 2007 at 03:24:45 AM MST
(User Info) http://web.archive.org/web/20050404022706/www.cc.jyu.fi/~hvirtane/cooker/

The first test, 900 rpm with the brass shaft was 84 watts for ceramic. 8 amps 3.5vac O.C.volts 4.65ac
Second test, 1900 rpm with the brass shaft was 225 watts for ceramics. 13 amps 5.78vac O.C. volts 8.83ac

Thank you for sharing your nice experiments.

Sounds good. With three alternators stacked you could maybe get a very cheap and easy direct drive PMG.

As well, you might try leaving one of the alts as it is and take the rotor current for that one from the others?

- Hannu

Re: Easy Auto Part Two (3.00 / 0) (#16)
by dinges on Fri Jul 6th, 2007 at 08:39:31 AM MST
(User Info)

Joe,

An enjoyable write-up on an interesting experiment.

It reminded me why I like this board.

Re: Easy Auto Part Two (3.00 / 0) (#17)
by GeeMac (foxunc@telus.net) on Fri Jul 6th, 2007 at 12:31:45 PM MST
(User Info)

Great story. I was inspired and went over to my local appliance guy and he gave me two microwave magnets. I have a GM Delco alternator. I got it apart, but I can't get the iron finger doodads off the shaft. How can I remove them? Is there a special tool?
GeeMac

Re: Easy Auto Part Two (3.00 / 0) (#18)
by WXYZCIENCE on Sat Jul 7th, 2007 at 01:55:33 AM MST
(User Info)

GeeMac, I have several ways of removing the claws.

#1 Remove the nut fan and pulley assembly.

#2 Replace the nut.

#3 Place the rotor on a piece of pipe supported well to a solid base.

#4 With the aid of a 20 lb sledge hammer I hit the nut end very hard and square.

#5 Once off the shaft the claws come apart easily.

I leave the nut on so I can grind the end and still have a thread if I got to hit it a couple of times. One out of ten don't fair to well with this method.

The second method is to take the rotor to a shop with a big press. They can push the shaft out for you.
Joseph

[ Parent ]

Re: Easy Auto Part Two (3.00 / 0) (#19)
by willib (willibur at comcast dot net) on Fri Jul 13th, 2007 at 12:15:41 AM MST
(User Info) http://www.njwind.com/webcam.html#

Joseph what do you think of putting small neos ON the inside of each claw finger?
i looked at an alternator just today ,its got very tight clearence between the claw and the stator..

since i dont have the machinery to turn a shaft down ,it would be great to try 1/2" X 1/2" round neos or larger ones
does the field winding come off easily?
i have two alternators on hand to try it out
it seems to me that if you were to put the neos right on the fingers of each claw that may work better?

ok a claw covers exactly three stator teeth i wonder if it will cogg?

i guess there is only one way to find out i have a bunch of 7/8"dia x 1/2" neos
i wish i could machine small flats on the inside of each finger...but hey ..
Carpe Ventum (seize the wind)
[ Parent ]

Easy Auto Part Two | 19 comments (19 topical, 0 editorial)

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