Basic Inverter Drive Mechanics; Torque; Rotator And Linear Operator Outputs - YASKAWA VS-626M5 Instruction Manual

Appendix

15.2.1 Torque

15.2 Basic Inverter Drive mechanics

15.2.1 Torque
15

15.2.2 Rotator and Linear Operator Outputs

This section explains the torque, motive power, and inertial moment that are the basis of selecting motor and
inverter capacities.
Torque is a moment of force that causes the rotation axis on the rotator to rotate about a center. As shown
in Fig. 15.7, when external force f (N) is used in a tangential direction at point P, which is separated by
the distance r (m) only from the center of rotation O, the torque T can be expressed using the following
formula.
T = f ⋅ r
(N ⋅ m)
P
r
f
O
0
f
Fig 15.7 Torque Definition
Also, as shown in Fig. 15.8, if a gearbox is used, the torque increases and decreases proportional to the
shifting gears, so taking motor axis speed N
lated torque T (NSm) can be expressed using the following formula.
M
N T T
L L L
T
= =
(N ⋅
a
M N
M
T
M
Motor axis
Motor
−1
N (min )
M
Fig 15.8 Torque when a Gearbox Is Used
Using torque T (NSm) on the rotator, the output P
using the following formula.
= 2πNT
P = 0.1048NT
R
60
As shown in Fig. 15.9, taking the force F (N), which is used on the speed V (m/min.) and the load, the output
P when performing linear operations can be expressed using the following formula.
L
= FV
P = 0.0167FV
L 60
V (m/min)
−1
N (min )
Bed
Fig 15.9 Linear Operation Output
−1
(min ) and load axis speed N
M
m)
Inertial moment
J (kg m
L
T
L
Load axis
Load machinery
−1
N (min )
L
during rotation at speed N (min
R
(W)
(W)
Ball screw
W (kg)
15 -6
−1
(min ), the motor axis calcu-
L
2
⋅ )
N
M
(Gear ratio a = )
N
L
−1
) can be expressed