a way to reduce cogging?

[daveyjones97]

when i first became interested in ebikes and thought making/adapting my own motor might be possible i came across the backshed site (beyond random i know). i just remembered the bit on cogging and thought of direct drive hub motors. im pretty sure any reducuction in cogging would be at least equalled by more inefficiency and loss of torque, but as im a truck driver not an scientist or electrician i thought i'd throw it up for folk to shoot at:
http://www.thebackshed.com/windmill/articles/decoggingFP.asp

 

[dogman dan]

Interesting. If you have any power left in your battery, 50w worth of throttle does wonders to remove cogging, and even assist a few watts.

Screwed if you got suprised by your dead battery though.

 

[John in CR]

Yeah, the 7 phase winding change sounds very interesting, especially since it didn't rob power as a generator.

 

[Miles]

As the article implies, though, "cogging" is just torque ripple, or uneven distribution of parasitic torque. The power requirement to overcome parasitic torque is not greatly affected by the amount of cogging.