3.2 Starting and Stopping Time
3 -3
3.2 Starting and Stopping Time
The motor starting (tr) and stopping time (tf) with a constant load are calculated using the following
equations. Motor viscous torque and friction torque have been ignored.
Starting time:
tr
=
104.7
×
N
R
(
J
M
+
J
L
)
Kt
⋅
I
R
(
α
–
β
)
[
ms
]
Stopping time:
tf
=
104.7
×
N
R
(
J
M
+
J
L
)
Kt
⋅
I
R
(
α
+
β
)
[
ms
]
N
R
: Rated motor speed (r/min)
J
M
:
Motor moment of inertia (kg/m
2
)...(GD
2
M
/4)
J
L
:
Load converted to shaft moment of inertia (kg/m
2
)...(GD
2
L
/4)
T
PM
: Maximum instantaneous motor torque obtained in combination with SERVOPACK (N
⋅
m)
T
L
:
Load torque (N
⋅
m)
To convert the motor current value into an equivalent torque value, use the following formula:
Motor torque constant
×
motor current value (effective value)
Motor torque
Time
Motor speed
Time
T
PM
T
L
Figure 3.2
Motor Torque
−
Motor Speed Timing Chart
3