If I reverse phase and hall wires, both, will the motor run in reverse correctly?

[chriswfoster]

My question is actually specifically related to hoverboard motors. But I'm wanting to make something 4WD/AWD with hoverboard motors.

They have 3 phase wires and 3 hall wires (a, b, c type).
My controllers are capable of doing "reverse", but I don't want to leave 1 side of the cart in reverse, and the other side in forward, the whole time. Unless that's how it's supposed to go when doing AWD?

My idea is probably flawed, but I was thinking if I ran my motor's phase wires in reverse (A,B,C to C,B,A), then did the same for my hall sensor wires... But leave positive and negative where they're supposed to go.
Again, just an idea. Let me know if I'm missing something.

 

[amberwolf]

There is often a different hall order for a reversed phase order, because the wires are often not "matched" inside the motor and/or controller for their order.

If a controller doesn't have a simple reverse function (often a single wire you connect to ground) or for whatever reason you can't do this in your wiring, you can try just reversing all the wires as you mention, and see if it works. But the reverse wire, if it simply reverses direction and doesn't change the system behavior in other ways (lower speed or power, like "trike mode reverse" sometimes does), is a perfectly valid way to do this.

If you later need to use the reverse function of the system as a whole, you can use a DPDT relay to control the reversing wires of all the controllers from your reverse switch.

If it does not run smoothly at low current (an amp or two at most) in the right direction at the correct speed when off the ground (no load), then you can try swapping the three hall wires in pairs, one pair at a time, until it runs correctly. There's only six swaps to try, so it's fairly quick and easy--just don't apply full throttle immediately, do it gradually so if it is not running correctly it won't put the wrong load on the controller and blow it up.

 

[chriswfoster]

Thank for that great answer.

I might do 1 side in reverse. I just wasn't sure if a controller could handle it for that long.

 

[amberwolf]

Unless a controller specifies otherwise, all a brushless controller does in reverse mode is send the phase signals (and read hall signals) in reverse order from normal, so the controller's loading is exactly the same either way.

Certain controllers use what is sometimes called "trike mode" reverse, where they limit speed and/or current (which limits motor power/torque) to prevent accidentally going "full-speed" in reverse and colliding with something. In those cases, the controller sees *less* load, heating, etc., in reverse mode than normal.

So in either case, reverse mode should not place any more load on the controller than normal.


An exception is with motors that have non-neutral hall timing (non-centered placement of hall sensors vs stator teeth/windings), that are designed to run only in one direction. This is uncommon, especially with hubmotors--it's more common with gearboxed "middrive" motors, to make them more efficient since those are generally only run in one direction and never reversed (some even have freewheeling clutches preventing reverse operation, as do most geared hubmotors, though the latter still usually have neutral timing).

With a non-neutral-timed (advanced or retarded timing) motor, it takes more current in one direction than the other to drive it if the controller does not automatically adjust it's timing to accomodate this (which I doubt most typical ebike/scooter/etc controllers do, though VESC might be an exception as it's pretty advanced).

So in that specific scenario, it might place more load on the controller (and motor) in reverse than normal. But I don't think you are likely to encounter that.

 

[chriswfoster]

Very informative. Thank you so much!