YASKAWA E-II Series - Starting and Stopping Time

4.5 SERVOPACK Overload Characteristics and Allowable Load Moment of Inertia
4
SERVOPACK Specifications and Dimensional Drawings
4-13
4.5.2 Starting and Stopping Time
The motor starting time (tr) and stopping time (tf) under a constant load are calculated using the following for-
mulas. Motor viscous torque and friction torque are ignored.
Calculate the torque from the motor current using servomotor torque constant × motor current (effective value).
The following figure shows the motor torque and motor speed timing chart.
n
M
:
Motor speed (min
-1
)
J
M
:
Motor rotor moment of inertia (kgxm
2
)
J
L
:
Load converted to shaft moment of inertia (kgxm
2
)
T
PM
: Instantaneous peak motor torque when combined with a SERVOPACK (Nxm)
T
L
: Load torque (Nxm)
tr =
tf =
Starting time:
Stopping time:
2
π
 nM (JM + JL)

(TPM - TL)
60
[s]
[s]
2
π
 nM (JM + JL)

(TPM + TL)
60
Motor torque
(current amplitude)
Motor speed
tr
tf
n
M
T
PM
T
L
Time
Time
T
PM
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