How hard is it to build your own electric motor

[prState]

If you wanted to build a working electric bicycle motor from various hardware bin parts (or electrical parts you could buy) how hard would it be?

note: not just a small hobbyist motor, like I've seen online, but something that would actually power the bicycle?

Easy? Not too easy? Hard? Difficult?

How often might you need access to a machine shop, for instance or other specialized equipment? If you succeeded, how crude would the motor be, or inefficient?

 

[prState]

If you wonder why I'm asking, I was thinking along the line of a universal kit bike. Or to use an analogy, if you draw up plans to make a wheel barrow, source all your parts, and can more or less find the parts universally, one can build that wheel barrow now, 5 years from now, or 10-20 years from now, as well as build one in China or New Zealand, or Borneo!

However, i don't think you need to reinvent the bicycle itself. Just the motor and or drive mechanism if any.

(this has resulted from thinking about Giant Twist dumping support -- it gets by having to depend on an external source, and wondering if or when they may move on or disapear - it also goes beyound the Cyclone model which still forces you into a unique system.)

 

[prState]

BTW, I don't think the idea necessarily threatens manufacturers. They can always offer better efficiency, amenities. Just like I might be able to build a kit car, but even with all the blueprints, I'm never going to produce a Porsche in my garage.

 

[JohnInStockie]

Given that we are still in early days, I think a Model T might be a better analogy rather than a Porsche

 

[prState]

True that!

Also, as far as a design for what I'm thinking of, the need for additional complex tools should be at a minimum ideally. On the other hand, if one can't build something reasonbly quieter, (than like the drill I just bought) no one will probably want to deal with that noise.

 

[flecc]

With the only sensible option a Hall effect motor, very difficult and not practical, and not only for the construction but even more the design, unless you were thinking of starting from an existing design.

Even starting with an existing design you'd need a variety of machine tools and the skills to use them, coil winding machine etc, you'd need knowledge of a reliable way of mounting the magnets in the rotor drum and mounting the Hall sensors in the rotor and knowledge of their exact positioning for optimum performance.

The spindle would need to be made from blank rod, drilled through from one end for the cable feeds and milled out for the internal side access for the cables into the rotor, then threaded and finally fully hardened. This is a very critical component, since being hollow and thin walled it has to do a tough job in relation to the motor stresses, bike and rider weight and road impacts. As for casting a motor casing and machining it subsequently, that's a whole story in itself. Even sourcing small amounts of the necessary materials would be very difficult.

It would all cost far more than a proprietary motor and perform far worse, if it ran at all. A non starter in my view.
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