Building a bigger motor out of 36V escooter hubs

[JacobsMess]

So I'm building an EV using the GS450H transmission. Whilst on the bench I wanted to do some experimenting with the input shaft that originally connected to the ICE.

The plan is to connect another motor to this and see if I can get the transmission to provide CVT to it and thus allow a greater gearing ratio and top speed.

I picked up 8 36V escooter hub motors for very cheap (£20) the other day, I only wanted 1 but he wouldn't sell just one so I took the lot.
I'm thinking they might not be quite up the task but figured I might do some experiments with them anyway and see how they do.

So, is there any simple way of combining them (just a couple not all 8!) into something more torquey? I'd planned on just mechanically coupling the armature and controlling them using one set of hall sensors, as I understand this should work ok it's more the easiest way of coupling them.

I have skimmed Farfles thread but that's a bit more involved and expensive than I'm willing to give to these things.

Anyway, any ideas?

The longer term plan is to use a HSG or Honda IMA motor for the job but before I buy one of those I figured I'd have a play with these.

 

[amberwolf]

The "simple" way is to bolt a sprocket to each one (to their disc rotor mounts if they have them since there are some already designed to do this) and chain them together. One of them will need two sprockets stacked far enough apart that a second chain can be used to drive the input of your system. Mount both to a frame in tandem, one in a regular "dropout" and the other in a sliding one to adjust the chain tension between them, and the entire frame sliding to adjust tension to the input.

One controller can run them both since they're physically locked together. You just have to position them first by using a DC power source. Connect each one's phase wires to the other's, so they are directly paralleled. (B-B, G-G, Y-Y). You'll only use one hall wire set if you're using a sensored controller, doesn't matter which one. Before connecting the chain between them, and before connecting the controller, use a low-current DC source, connected + to say, B, and - to say, G. This will put both rotors into the same position relative to each other. While it's locked this way, connect up the chain. If it won't go on this way you'll have to line up the sprocket on one of them to match the other so it will.

Once it's locked in a perfectly aligned position, a single controller will run both motors as if they were one. The inductance and resistance will be half of what it was with one, and the current doubled, so the controller will need to be able to handle this.

 

[amberwolf]

The more complicated simple way is to parallel them axially instead, with a stiff coupler on their axle ends, and a collar coupler between their flanges. (like a big pipe). A smaller diameter coupler could be used between their disc rotor mounts, but you have to take their covers off to run the bolts thru the rotor mounts from the *inside*, and then bolt the resulting "dumbell" back to the motors.