Re: Basic Servo Motor Question...

Dan,

If you are planning to use a STEP and DIRECTION input DC servodrive
then a tachometer is not necessary. It will derive all PID
information from the encoder.

It sounds like you have a good motor there. Make sure the encoder is
a "quadrature" type. What is the line count?

Regards to what you can get out of the motor; please refer to message
#9342. It goes into a little detail on that subject.

Mariss

--- In CAD_CAM_EDM_DRO@egroups.com, djr@n... wrote:
> I want to jump in head first in a CNC servo sherline mill
conversion,
> but I am really ignorant when it comes to DC servo motors and
> drivers.
>
> I see that some servos have slotted encoder wheels with optical
> detectors and/or tachs and/or brakes. I can see what the slotted
> wheels and brakes do... the tell position and stop the thing, but
> what
> is the need for tachs? Can't you tell position AND speed with the
> optical detectors? What motor stats are important for me if I am
> going to use a servo motor with the sherline? Does stall current x
> volts (watts) tell me something? What RPM range is good?
>
> I was browsing a local surplus store this past weekend ran across a
> servo motor with one of those slotted wheels and an optical
detector
> circuit board attached still in the anti-static wrap. It was made
by
> Japan Servo and it's rated at 24v 3000 RPM. It is about 3" in
> diameter and 5" long. I don't have any other data on it. How can
I
> determine if this motor is a good candidate for the sherline? At
12
> volts it really seems to have a good bit or torque.
>
> Thanks in advance for any answers... Pointers to "servo CNC motors
> and drivers for dummies" websites would also be great!
>
> Thanks
> - Dan