Re: [CAD_CAM_EDM_DRO] fanuc ac servo motor

riverwind1962 wrote:

>does anyone know what hardware is req to use fanuc ac servo motors i
>have aquired 4 of them and they look good any ideas
>
>

Most of the "big name" servo drives are proprietary. They use some odd
combination of encoder signals to provide commutation as well as encoder
position info. The scheme is such that they can either tell the correct
phases
to drive totally statically, or they can determine the correct commutation
by moving the motor only a couple of encoder counts in any direction.
This makes it very hard to mix and match drives and motors.

The generic motors/drives usually use a standard quadrature encoder and
separate commutation signals with 3 tracks. These are often identified as
"hall sensors" although in many cases they are provided by additional tracks
on an optical encoder.

The motor itself is probably a 3-phase "brushless" permanent-magnet motor.
There is some confusion due to the original misuse of the term "brushless
DC motor" in this application. Those fans in PC's and such used the same
designaltion, but it was essentially correct, as the entire commutation
system
was built inside the motor. The servo motors were misnamed, because the
commutation was NOT in the motor, but in the drive. A more correct term
would have been "permanent-magnet brushless motor" or "synchronous AC
motor".

You need to determine if these are permanent-magnet or induction servo
motors. An easy test is to connect a voltmeter to any two of the motor
leads and rotate the motor. If you get tens of volts out when turning it by
hand, it is most likely a permanent-magnet motor. If you get very little
voltage out, it is most likely induction. It takes a different drive design
to drive the two types.

Jon