Anotherpower.com Forum
Project Journals => User Journals => Bryan => Topic started by: Bryan1 on January 03, 2012, 02:59:28 am
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G'day Guy's,
Back in 2009 this was my first motor conversion based on a brandnew 2hp 3 phase motor. I machined up a new rotor out of solid bar stock for it.
[attachimg=1]
Rather than go with the twisted pole I went with the offset method and went 43.5 degrees for each pole.
[attachimg=2]
I used 8 off 2x1x1/2 neo magnets with a countersunk hole. I superguled and screwed each magnet down then cast the rotor in epoxy.
[attachimg=4]
Here it is installed in the motor.
[attachimg=3]
This genny has been going on my shed array ever since i put it up, it has a 3 metre diameter blade set which was also the first blades I ever made. The genny has seen a heap of 100k + winds over the years and it laps it up and often tops out the 20 amp gauge I have set up for it. As it does use stock winding I do want to take it down one day and do a full rewire so I can get the best potential out of those neo magnets.
I'll take a new pic of the genny on the tower soon and update this post with it
Regards Bryan
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looks like a nice build, very clean job.
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yep, looks like a nice one going up!
How much beer did it really take to get it finished? 8)
Tom
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Hi Bryan ,
Is there 3 layers of coils, eight coils/layer??
Is that the reason for a rewind ,to put more coils in , shorter tooth span, so more flux linking the coils?
With 1" wide poles should the coil span be ~the same or does the laminated core teeth change things??
Thanks.....artv
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ArtV,
The motor is a stock standard 4 pole 1.5Kw (2hp) with the original windings and each pole on the rotor is 2 magnets side by side so the magnet poles went NN-SS-NN-SS. Now the whole point of me wanting to do a rewind is to use thicker wire and have all 6 or 12 wires coming out for different configurations so I can get the most power out of it.
Regards Bryan
P.S. Tom it was a while ago but one would have to say as it took a couple of months to make probably close to a pallet of beer was consumed in the making........
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"P.S. Tom it was a while ago but one would have to say as it took a couple of months to make probably close to a pallet of beer was consumed in the making........"
Does this mean the cost of the motor , magnets and machining........ pale into insignificance in the total cost benefit equations?
Artv.
In the original windings, the slot length and the loop length (joining the wires in the slots)can be of equivalent length in the outer concentric coils. Going to closer slot geometry helps get the wire resistance down as well (shorter loop ends)..... however in this type of alternator, it will be the armature reactance that will probably determine the upper current limit.
If it were only resistance they wouldn't just run away under short circuit high wind conditions...... they'd burn up instead.
The coil span should be the same as the magnet span. In this case 2" or so.
The flux linking the coils will be governed also by the magnet strength, proximity to the core and the resultant reactance too. As the reactance increases, it tries to mess up the incident flux, and so weakens it's effect. This flux .... no longer linking the coils is leakage, and the flux will take some other path home rather than the circuit we designed for it.
..................oztules