Appendix
A.2 Motor selection
SINAMICS V90, SIMOTICS S-1FL6
422
Operating Instructions, 04/2019, A5E36037884-007
A.2
Motor selection
A.2.1
Selection procedure
1.
Determine the mechanism type as well as the detailed data of the related mechanical
parts, such as ball screw lead, diameter, lead, and gear diameter. Three mechanism
types are shown below:
Belt transmission
Ball screw
Rack and pinion and/or gear
2.
Determine the operation pattern including such parameters as acceleration time (t
a
),
constant motion time (t
u
), deceleration time (t
d
), stopping time (t
s
), cycle time (t
c
), and
travel distance (L).
3.
Calculate load inertia and inertia ratio.
The inertia ratio can be obtained by dividing the load inertia by the rotor inertia of the
selected motor. The unit of inertia is x 10
-4
kg·m
2
.
4.
Calculate the speed.
Calculate the speed according to the travel distance, acceleration time, deceleration time,
and constant motion time.
5.
Calculate the torque.
Calculate the torque according to the load inertia, acceleration time, deceleration time,
and constant motion time.
6.
Select the motor.
Select the motor that matches the data in step 3 to step 5.
