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Discussion Starter · #1 ·
Hello all I’m new to the forum but am hoping some of you may be able to help me out.

This is not strictly EV related but hope what I learn from this will be of use to me when I start my EV project.

I wish to build my own dc brushless motor capable of spinning a mass (flywheel) of 6kg to 8000rpm, at which point the power with be cut and the stored rotational energy will be fed back through the motor to generate power to charge a small gadget (thinking my mobile)

Input power will be from a small PV solar panel whatever i can get cheap or diy 6V around 1A, and on the generating side I will need 5V @ 1A. This is to keep the output same as my phone charger.

I’ve now got the flywheel maths sorted and 6kg @ 8000rpm = 36000J or 2A or 10W (enough to charge 1400mAh phone)

I think I’ve settled on a motor design type but suggestions welcome. being of a brushless, radial flux, 3phase, hollow core, out runner with coil stator in-between twin magnetic rotors.

This is to be done on a budget and so I would like a pretty good idea of what’s involved before heading out and buy all the bits.
What I’m looking for is some direction in terms of number of coils and turns of wire to achieve the design output.

Hope someone can help and let me know if I’ve missed something.

Thanks
Ricky
 

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I wish to build my own dc brushless motor............What I’m looking for is some direction in terms of number of coils and turns of wire to achieve the design output.
Hi Ric,

That's part of the DIY motor build.....figure out T/C yourself :) I don't care how good of a motor engineer a guy is, he can't give you a number for that without a great deal of analysis, meaning time, meaning money.

Now I think it is great you want to mess about with motors. Best way is to get one you think is about the right size and tear it apart. See if you can put it back together and have it work. Measure input and output. Now repeat but change something. How did that affect the input and output? Repeat and repeat. After you screw around with enough of the little buggers, maybe you figure out what your doin' ;) Either that or enroll in engineering school :)

I think flywheel energy storage for your described application is a poor choice compared to a dump battery. But again, it's your project.

Regards,

major
 

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Discussion Starter · #3 ·
Ok i take your point, i was just looking for some equations that could give me a ball park figure.

the more i think about it the more questions i have, i think need to improve my knowledge. can anyone point me to a good resource on making dc motors?

the burning question at the moment is ive seen and been told the type of motor im on about can get to very fast rpm (like the 8000 quoted) but im unsure how? and will it still have any torque at the top end. will it even get there on 6V 1A?

As for the flywheel been a poor choice, think of it more as a lesson in alternative energy storage and motor design :)
 
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