Re: [CAD_CAM_EDM_DRO] Servo Motor Make Up?

John Delaney wrote:

>I've been sloggin' through the archives back to Jan '04, so far.
>Things are getting repetitive but I can't find a simple statement on
>this.
>
>Is a servo motor simply a "normal" DC motor with an encoder?
>
>

That is pretty close. Many ordinary DC motors are quite acceptable
for positioning servo use. The one place a few motors fall flat is in
the area of torque ripple or velocity ripple. This is a periodic
fluctuation
in either torque or speed, due to some shortcuts in the magnetic design
of the motor.

It is possible to find motors with encoders that will not perform well
in a CNC positioning servo, however. These might have been used
in such a way that the encoder provided speed information, but the
motor was never needed to precisely position something at low speeds.

But, in general, if you find a DC brush or brushless motor with an encoder,
it probably will qualify for servo use.

Jon