-dg
1 kW
I may be misinterpreting spinningmagnets statement, but I took it to mean that the rotor bowl could be reduced by 1/4. Not that the whole motor could be reduced by 1/4.speedmd said:I could easily remove about 1/4 of its weight.
Agree, 1/3 is possible in most mass produced items without too much structural loss. That would bring it down to around 3- 3.5 KG? I don't have one to look over and only going by photos but could aluminum replace the axle possibly as it is used mainly as a stator spacer / bearing supports and also thinking the planet gear support can be made more swiss cheese style.
My point was that while there is some scope for lightening, it is not all that much. The major masses are the stator core, the stator copper, the magnets, and the magnet backing. These can't really be lightened without compromising function or fundamentally changing the design of the motor. The other parts, the axle, the shell, the clutch, the stator support are either aluminum or relatively small. Sure the axle is heavier that it needs to be, and some weight could be turned off the shell, especially if they do not have to hold a bike up, but it just isn't that much compared to the copper, laminations, magnets, or backing iron.
I'd be surprised if 1/4 of the weight of the BPM could be eliminated and completely flummoxed if 1/3 could, even for a mid drive conversion. I'd love to see it worked out, so if you have specific ideas on how to do it, please identify what parts are modified and how to save 1.5 kg from a 4.6 kg BPM.