Re: [CAD_CAM_EDM_DRO] Re: DC motor controller

Hi John,

The servo drive will have to work to reduce the effect of the cogging.
Modern drives are pretty good and can mask most of it. On my mill, if I
watch the pulleys very closely I can just see the motor speed varying
slightly at certain feed rates. It appears to have no discernible
effect on accuracy or surface finish so I don't worry about it. Higher
CPR encoders make it easier for the drive to compensate.

Les


John Hansford wrote:

> Hi Dave,Ron,
>
> Pictures...
> http://www.flickr.com/photos/26361144@N00/
>
> I took the CW to mean the nut would probably fly off if it ran
> the other way. I opened it ...Nothing flew apart.
>
> What's the Bad news...How _BAD_ could they be as servos?
>
> I wouldn't have noticed the very slight cogging if I weren't
> trying to find it.
>
>
> John
>