Can motors self-energise?

[TwoBikes]

The front hub motor on one of our electric bikes has started to engage itself. This seems to happen while going downhill and braking with the front brake. It stops doing it after a couple of seconds and the brake easily overcomes the effect. Does anyone know what might be causing this? Thanks.

 

[Mussels]

The front hub motor on one of our electric bikes has started to engage itself. This seems to happen while going downhill and braking with the front brake. It stops doing it after a couple of seconds and the brake easily overcomes the effect. Does anyone know what might be causing this? Thanks.

The motor on my bike switches on for no apparent reason when coasting, stays on for a second and switches off again. I'm not moving the pedals or touching the throttle. I've never had it happen whilst the brake cutout is activated though.

 

[flecc]

The only cause I can think of here is if the roller and ramp freewheel starts dragging, spinning the motor and causing it to generate for a moment. The back EMF is then likely to kick it back off then.

 

[TwoBikes]

Thanks both. It's not just me then.

I forgot to say that the front brake has no cut-out switch, so there's no electrical connection between it and the motor or controller.