I'm looking at the possibility of driving a larger sprocket with two or more identical motors from a single VESC. If my understanding is correct, if I wire the motors in parallel from the VESC and synchronize them before locking their movement to the sprocket via a pinion/spur gear, they should all run happily from the one VESC then. Even via hall sensor, there will essentially be a master motor and the others will follow happily. I have heard applying a DC current to a single phase on each motor will lock each one to the same position, but I don't know how accurate this is, or if I need to use a scope for example. Will the mechanically locked motors run in senseless mode too ok? My understanding is nothing needs to be done in VESC configuration other than setting up as if one motor once synchronized?
please, read the links
https://vesc-project.com/node/981
https://vesc-project.com/node/980
You mean like this? Within each rear tire is a BLDC hub motor. 4 motors total which are driven by 2 VESC 6+'s.
You are correct that the rotors and stators need to be mechanically locked in position relative to each other. I machined new axle's for this setup to accomodate 2 stators (these are outrunner hub motors) which are keyed to the same alignment.
For the rotors, I used a regular old magnet to determine the polarity of the permanent magnets and marked -'s on them. All BLDC motors will have magnets arranged in alternating polarity. The alignment of the rotors is determined by the magnet polarity and nothing else, so with 30 magnets in each of my motors, there are 15 different positions that will work equally well.
I made the aluminum center ring such that the rotors would bolt onto it with the magnet poles in alignment.
Lastly, the phase wires need to be connected in parrallel. Connect each colored phase wire to the same color phase wire from the other motor, and to one of the phase wires coming from the VESC. Basically, its a Y-connection on each phase. If you have sensored motors like I do, you only use one of the sensor harnesses, and the other doesn't do anything. You can remove the sensors from the other motor or leave em. It doesn't matter. Nor does it matter which motor you choose to use the sensors from.
And that's it! Double the torque, double the current draw, and double the fun.