
4. SELECTING A MOTOR
B–65142E/04
DESCRIPTIONS FOR THE α series
38
If the load conditions (cutting load, acceleration/deceleration conditions,
etc.) vary widely in a single cycle, write a time–torque graph according
to the operation cycle, as in above item. Obtain the root–mean–square
value of the torques and check that the value is smaller than or equal to
the rated torque (condition 4).
t
1
t
2
t
3
T
1
t
4
t
5
t
n
T
2
T
3
T
4
T
5
T
n
t
o
Torque
Time
Trms +
T
1
2
t
1
) T
2
2
t
2
) T
3
2
t
3
)AAA ) T
n
2
t
n
t
o
Ǹ
to = t
1
+ t
2
+ … + Tn
NOTE
When the motor is being operated at high speed for a
comparatively large proportion of the time, you must take
the rotating speed of the motor into consideration and
evaluate whether output can be specified in terms of a
continuous operation torque.
Calculating the torque in
a cycle in which the load
varies