Author Topic: Report KD 644 about 8-pole PM-generator available  (Read 378 times)

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Adriaan Kragten

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Report KD 644 about 8-pole PM-generator available
« on: November 15, 2017, 03:34:42 AM »
Report KD 480 has been replaced by report KD 644 which can be copied for free from my website: www.kdwindturbines.nl at the menu KD-reports. The title of KD 644 is: "Ideas about an 8-pole, 3-phase permanent magnet generator with a stator without iron in the coils, using eight neodymium magnets size 80 * 20 * 10 mm and a housing of an asynchronous motor with frame size 71".

The generator is meant for a rotor with a diameter of 1.5 m. Although the magnet and copper costs of this generator are rather high, advantages are that the generator is completely closed, that it will have a low sticking torque and that it will have a high efficiency because there are no iron losses and because there is enough space to use thick copper wires for the winding. The generator is not yet tested.

bigrockcandymountain

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Re: Report KD 644 about 8-pole PM-generator available
« Reply #1 on: November 15, 2017, 06:30:49 PM »
This seems a good design.  I just quickly read it but does it have to be aluminum housing?  Where would one get delrin or something for the stator?   Would you use the same pole number for a larger machine?  I won't be testing it for awhile.  I have a tower to finish for the one i have. 

It seems to be the best of both worlds.  Rugged and sealed like a motor conversion and efficient like an axial.


Adriaan Kragten

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Re: Report KD 644 about 8-pole PM-generator available
« Reply #2 on: November 18, 2017, 04:45:41 PM »
I think that this generator principle also works for a cast iron housing but an aluminium housing is most standard for small asynchronous motors in Europe. The disadvantage of a cast iron housing is that more of the magnetic flux will flow through the housing but as the distance in between the housing and the magnets of the armature is rather large, the losses in the housing due to eddy currents will probably be still low enough.

The material for the stator body can be any material if it is non metal, so it should guide no magnetic flux nor an electric current. In The Netherlands, Delrin is very generally available. It is one of the brands of POM (polyoxymethylene). Another brand is Ertalon. The main advantage of POM is that it keeps its measures.

The advantage of an 8-pole armature is that the stator winding is rather simple. For bigger housings you can use larger magnets or you can increase the pole number but the pole number must be devidable by four for a 2-layers winding. So the next pole number is 12 en then the stator will have 18 coils.