I see this term used. What is does cogging mean?
I have DDs whose motors 'cog'. Theoretically awful — but I hear no deleterious effects, sounds utterly smooth and pitch-stable to me.
Cogging is a bad thing in any turntable motor, regardless of how it drives the platter.  With belt-drive, it could be even more annoying and noticeable than with DD.  But the fact is that in most any modern turntable of reputable design, motor cogging should not be an issue, even if it's happening. 

bimasta, If you hear no issues with the turntables you own, then how do you know the motor is guilty of cogging?  Is it merely because they are iron core motors?
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