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[TheRan]

I think you're just using different descriptions for the same noise. There should be no noise pushing the bike while it's off and if there is then it's something mechanical like dodgy bearings.

[Crissa]

No, something turns on if the bike is pushed.  My washing machine does the same thing.

-Crissa

[TheRan]

Mine doesn't although it's a 2019 so maybe it's a thing with older bikes. I don't see how it would work though (it would need to continuously apply power to the motor to know it's being rotated) nor what would be the point of doing it.

[ESokoloff]

Here is an explanation on brushless DC motors that SHOULD (or at least help) clear up some of the confusion of what’s going on with the Zero Z-Force motors.

https://www.radiocontrolinfo.com/brushless-motor-cogging-explained/


Fast forward to about the 5:00 mark in this video also

[Crissa]

The motor creates power when it's pushed.  There doesn't need to be any power applied to it.

-Crissa

[ESokoloff]

Those videos were meant for the likes of TheRan.
Your convinced that the motor noises are a pedestrian warning system & no one will be able to convince you otherwise.

[TEV]

(Sorry Crissa, your wrong).

Don't worry, she always make wrong/useless comments, I don't read her posts anymore .

Tom

[TheRan]

If there's any cogging with the Zero motor I certainly haven't felt or heard it when pushing my bike.

[ESokoloff]

If there's any cogging with the Zero motor I certainly haven't felt or heard it when pushing my bike.

I just tested my 16 DSR that’s currently (see what I did there  charging & found that if pushed VERY slowly nothing happens but if pushed fast the motor will make noise. Doesn’t mater if kick stand is up or down.
LCD display while charging only shows SOC & this goes blank when pushed forward but not backwards.

[ESokoloff]

I did a bit more testing yesterday & find that as long as the contactor is pulled in, the motor will make noise/cog (ever so slightly) when pushed at a significant speed. Key position, side stand, & kill switch make no difference (Note that contactor is only pulled in if charge cord is plugged in to live mains &/or key is on).

As the second video explained, when a motor is subjected to voltage/current, back/counter EMF (Electro Mechanical Force) is produced & the motor controller uses this to determine rotor position & even direction of rotation. 

Crissa is correct in that the motor creates a small EMF either naturally or via a slight power assist.
I’m thinking that the controller uses this to sense rotor motion & when rotation (speed) is great enough, more EMF is applied which yields greater back EMF so controller can pinpoint rotor position & that’s the cogging sound we hear.