Sources For Neodyn Magnets

If you're doing web searches, you'll get better results using the spelling Neodymium.

I think you would be better off buying a finished generator from one of the many many people who make them.

You can also get permanent magnet DC motors in the 60 volt area that were used on tape drives on ebay for under $50.

These make good generators to start with. But 4 and take one or two apart and see how they do what they do.

You can also buy low inertia DC PM motors. Cost more, but less weight uop on a pole. Boater sites have dozens of wind generators as a high % of sailboaters have a wind generator with them for power.

For sources, here is a list to google:

Forcefield, K&J Magnetics, National Imports, United Nuclear.

You are correct about thin magnets. Not very effective. The surface area is not as important as the proportion of the shape. A magnet with a thickness no less than half its length is a good starting point for experimentation.

tcorn

Here are the contact details for a company from China, with whom I have dealt. I got good quality and cost effective magnets of rare earth.

All the best

China National Electronics Import and Export Hubei Company

319 Wuluo Road,Wuchang, Wuhan, Hubei,China 430070 Tel:+86-27-87880050,87885904,87885905

Fax:+86-27-87883774 E-mail:tom49111@tom.com, shirley9@public.wh.hb.cn

Thank You Very Much.

Tom Cornell

Just go to eBay. They sell a bunch of them. I got two 1,000 pounders there! I have to keep them at least 30 feet from my TV!!!

I bet they were a nuisance to ship UPS.

He did a fantastic job of shipping them. He put them in a box about the size of a car battery (each came separately). The box was made from a really stiff form of corrugated cardboard. Inside of the box, each face had a piece of sheet steel the same size as the face - also top and bottom. Seemed to work really well as shielding and they managed to make it through the USPS!

And, I can't explain to you how insanely powerful these things are! if they grab iron, it literally takes 1,000 lbs of force to get them apart. The best comparison I can make is this is what working with high voltage is like, except it's with magnets!

good method of shielding. Price and weight?

Thank You

I am well aware of ebay. I am looking for a serious source to buy hundreds of magnets at a reasonable cost. Thank You for any serious leads.

More important, I was hoping for some insight concerning power production as a function of magnet shape. Come on engineers. I can buy magnets of all shapes and sizes. Not one book that I have researched tells the difference in use. A retangular magnet has the flux density spread out over a larger area than a cube shaped magnet. Both have the same volume of magnetic material. It is not clear if a larger area magnet results in a larger current flow in the coils. The total magnetic prduct is a function of the mass and rating of the magnet material. The charts that I see are not clear as how shape affects the flux. One spreads the flux density out while the other is concentrated in a smaller area. Does one perfom more effiently. I am looking for the most efficient design for a windmill project. Should I buy cube magnets or be looking for a retangular model.

Thank You.

Tom Cornell

well, in a motor design you have to calculate the ampere turns that is provided by the electricity that creates the magnetic field that interacts with the PM field. There needs to be a large enough PM that the created field does not exceed the PM field because once this happens I think you have maxed out your motor. Not being a motor designer, and I go from my DC motors class in 1958 when fields were usually made with coils of wire and a field current and when you had to have such a balance.

Suggest you look up coercivity and remanence and try these sites.

http://www.google.com/search?hl=en&q=%22PM+motor+design%22

http://www.bodine-electric.com/Asp/PutStream.asp?Context=/handbook/pdf/bodinehandbook_all_chapters.pdf

I respond to this question only reluctantly as Maxwell's equations have long since faded from my realistic useage, although I do recall that del cross b = D dot

X ß= ?? where's the D^.?? and the vector sign?

My brain is no longer permeable to these equations, and I can only respond diffusely.

The question you ask is not clear, I think. What you are interested in is the flux density of the magnet at a distance: something to do with Stokes Theorum if I recall correctly.

thus your question (I think) should derive from from the design of the rotor or stator, it's shape and size, and then back into your magnetic field needs. Magnets of a given material, such as neodymium-cobalt-iron will generally have the same "flux density", but obviously bigger ones have more of it, and thus induce more current in a given wire passing thru it at a given speed.

Yuk! i HAD 4 semesters of "electricity and magnetism", but then got wiped out on a follow on course by Professor Barnes "Elementary Electricity and Magnetism", which taught me to never take a course when the instructor wrote the book..

Yowza, that course made a eng-i-neer outa me.