Parker Motionsizer: Stationary Rack, Moving Pinion

For applications where the Rack is stationary and the Motor & Pinion are moving, set the rack's weight to an insignificant non-zero value.

Then for any additional load to the motor, set this with the Weight Only pull-down in the Axis Design screen. After selecting the motor, reiterate the sizing, adding the motor's weight (plus the gearhead if there is one) to the Weight Only value.