RE: [CAD_CAM_EDM_DRO] step/dir servo (Gecko drives)

I was using various motors and encoders. The encoders went from a 1000 slot
disk (Required too high a pulse rate for it to be successful with EMC, but
other programs may give different results), 400, 250, and 200. This is the
slots and all were being used as 4X giving 4000, 1600, 1000, and 800
effective steps per revolution. The parameters in EMC were set for 10 motor
rotations = 1" table motion. If you were using a belt drive like are then
the 1000 slot encoders would probably work fine and the 200 slot may have
too coarse a resolution.

The difference in maximum feed rates was based totally on the motor if I
discount the setup with the 1000 slot disk. The slowest was actually the
biggest motor with the 200 slot encoder. What seems to be the limit in my
testing is the maximum rpm of the motor. If I take the same motor that had
the slowest max speed and just hook it up straight to a DC supply of the
same voltage as I was testing the servo drives with I get approximately the
same rpm.

So, while torque is certainly an issue particularly when installed on a
machine there is also a finite maximum speed that any particular motor will
go.

Tim
[Denver, CO]

> Tim -
>
> Are you qouting those speeds using the same slot-count encoder
> with the same
> pulse-rate output from the LPT software for each motor? What are those
> numbers? For a given encoder and pulse-rate, what accounts for the
> variation in max. feedrate? I would have guessed they should be
> the same as
> long as there was enough torque to accelerate the system to speed.
>
> Carlos