Sat Feb 20, 2010 10:11 pm
A research paper on the effects of cogging
I happened to acquire this paper written in 2000 (PDF 189 Kb).
http://www.gotwind.org/images/cogging.pdf
It relates to cogging torque in hard disk drive spindle motors but has a direct comparison to alternator design.
It's fairly technical, but may of interest to some here, I appreciated it.
Abstract-
During the past five years, cogging torque in
HDD spindle motors has decreased drastically as
designers and manufacturers have developed a better
understanding of the cogging phenomenon. This paper
examines various methodologies of cogging torque
reduction. Timing techniques such as dead zones and
tooth notching, smoothing techniques such as
sinusoidal magnetization, and geometric techniques
such as tooth crowning and slot skewing are identified.
Cogging torque waveforms are examined in frequency
and time domains. Recommendations for accurate
cogging torque prediction and design of magnetizing
fixtures for low-cogging motors are forwarded.
http://www.gotwind.org/images/cogging.pdf
It relates to cogging torque in hard disk drive spindle motors but has a direct comparison to alternator design.
It's fairly technical, but may of interest to some here, I appreciated it.
Abstract-
During the past five years, cogging torque in
HDD spindle motors has decreased drastically as
designers and manufacturers have developed a better
understanding of the cogging phenomenon. This paper
examines various methodologies of cogging torque
reduction. Timing techniques such as dead zones and
tooth notching, smoothing techniques such as
sinusoidal magnetization, and geometric techniques
such as tooth crowning and slot skewing are identified.
Cogging torque waveforms are examined in frequency
and time domains. Recommendations for accurate
cogging torque prediction and design of magnetizing
fixtures for low-cogging motors are forwarded.