Alternator rotor magnet pattern question

Thread Starter

henry newton

Joined May 5, 2008
11
1. In an axial flux alternator, the poles of the magnets are arranged or alternate in a N-S-N-S pattern around the circumference of the rotor disk.My question is,will the axial flux alternator generate electricity if the poles of the magnets are arrange in a (let say) N-N-N-N pattern around the rotor disk.If yes what kind of current will it generate (d.c or a.c).I personally expect a d.c.Although i have not perform this experiment.I would like for you guys to experimentally confirm this.







2.I live in Nigeria, and believe it or not there is no place where one can buy neodymium magnets and i am badly in need of them.so i would like for someone(i mean a member of this forum)living in the US to buy some for me.Of cause i will have to send him first the money through Western Union Money Transfer and the magnet would have to be delivered via either UPS,FedEx or DHL.which ever one is most suitable for this kind of delivery.

If anyone is up to this,please email me at ( <snip>). I will send you the specification of the neodymium magnets that i want and you will find out the total cost, plus cost of shipment in dollar ( prefarably in Nigeria Naira if you can do the conversion or compute the exchange rate).Also you will have to tell me what personal data you need from me to facilitate the transfer of the magnet via either UPS,DHL or FedEx .You will send me your personal data that will allow me to send the money via Western Union Money Transfer.



email me at <snip>


Thanks

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jpanhalt

Joined Jan 18, 2008
7,691
International shipping from individual to individual can be very expensive. The lowest rate I got yesterday for a 5 Kg package from USA to England by DHL was more than $150 USD. Commercial entities get much better rates. So, if you can find a vendor (Farnell?) with the magnets you need, the total price would likely be less.

Americans have become very cautious about releasing any personal information, particularly information with any type of banking connection. Unfortunately, Nigeria has been home to a large number of financial scams. I don't doubt your sincerity in this request. You are probably just a victim of that reputation too. However, it is another reason to deal with a commercial entity.

I hope these comments are helpful. They are not meant to cast suspicion on you or your country.

John
 

Thread Starter

henry newton

Joined May 5, 2008
11
Hi John i really want to thank you for your kind and informative response to my last post.I have absolutely no idea that it cost that much to send a package from individual to individual.However the total price of the neomagnets ,magna-view fluid and magnetic viewing film i wanted to buy would cost roughly $35 dollars.That is the estimate i got from one of these site sell those stop.But the problem was the medium of payment they all required ( visa credit card, master card and other method of payment) which would make it impossible for me to place an order in their site,and to add to that they don't ship to Nigeria ( it is basically to places in Europe,Asia, America and a few north Africa countries like Egypt). It was really frustrating to me seeing or reading all these restrictions and should i say isolation place on NIGERIA.but i guess they have good reasons for doing that as well. I have tried FARNELL that you suggest but it turned out to be a dead end.What i am considering right now is to see if i can get a supplier or distributor in place like South Africa that ship or take orders from Nigeria.That could be my best bet, maybe.ALL the same, thank you and have a nice day.

Henry Newton.
 

TechMate

Joined Mar 24, 2010
1
1. In an axial flux alternator, the poles of the magnets are arranged or alternate in a N-S-N-S pattern around the circumference of the rotor disk.My question is,will the axial flux alternator generate electricity if the poles of the magnets are arrange in a (let say) N-N-N-N pattern around the rotor disk.If yes what kind of current will it generate (d.c or a.c).I personally expect a d.c.Although i have not perform this experiment.I would like for you guys to experimentally confirm this.

I found this old unanswered question when searching for other things.
The thread might be finished, but it might be of interest to have an answer to the technical question any way.

The answer to the question is a AC, but much weaker.
You must first consider where the magnetic flux lines are flowing, i.e. as many big loops from one en to the other end of the same magnet.

Current is generated in an electric wire when the wire is cutting through the magnetic flux loops.

As they are loops, the wire has to cut through the loop twice. First when getting into the loop and second when getting out of the loop.
The direction of of current will change as a consequence of whether the wire is going out or in to the loop.

When having magnets located N-N-N as described the quote. The loops are orientated more or less as old flowers i a vase, i.e. the flowers are hanging down on the side of the vase. The vase represent the magnet.
Now if You want to cut through the flowers just on top of the vase with a wire, you may notice that you first start cutting into the loops, but when coming closer to center of the vase you are cutting out of some loops while still cutting in on others. Some loops in the center of the vase will be cut in different directions simultaneous. Finally you will be cutting out of all loops.

From this we can draw the conclusion that it is very inefficient way to design an alternator. Even when considering a single wire we have forces working against each other.

To correct the weaknesses above the magnets are located N-S-N-S and preferably a second disk magnets located S-N-S-N
The disks are located so that a N on one disk is close to S on the other disk.
The magnetic flux will now look very different. The strong flux will between the closest N-S poles.

Now You can insert coils of wire between the disks. The mid diameter of the coil should be the same as the c-c for the magnets. In this way the one part of the coil is cutting out of a N-S flux as the other part is cutting in of a S-N flux. This means that both actions work in the same direction.


Regards TechMate
 
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