Yaskawa Varispeed 626M5 - Manual (Page 289)

15.3 Determining Drive Capacity
15 -17
15.3.3 Calculating Start and Stop Times
After selecting the machine characteristics and Inverter capacity, the start and stop times can be calculated
using Table 15.6. For the motor characteristics, refer to 14.1 Drives.
Table 15.6 Formulas for Calculating Start and Stop Times
Item Calculating from Torque Calculating from Output
Motor Characteristics Torque (NSm)
T M
0 N B N MAX
Motor
speed
(min
−1 ) Fixed
torque Fixed
output
Output (kW)
P M
0 N B N MAX
Motor
speed
(min
−1 ) Fixed
torque Fixed
output
Fixed Torque Characteristics
(0 ≦ N
M ≦ N B
)
0 ↔ N
M
Acceleration/deceleration Time
t = 2 π
60 ⋅ J M
⋅ N
M
⋅ 1
T
M
t =
 2 π
60
 2
⋅
J
M
1000 P
M
⋅ N
B
⋅ N
M
Fixed Output Characteristics
(N
B ≦ N M ≦ N MAX
)
N
B ↔ N M
Acceleration/deceleration Time
t = 2 π
60 ⋅ J M
⋅ 1
T
M
⋅
N
M
2 –N 2
B
2N
B
t =
 2 π
60
 2
⋅
J
M
1000 P
M
⋅
N
M
2 –N
B
2
2
Fixed Torque + Fixed Output Characteris-
tics
(N
B ≦ N M ≦ N MAX
)
0 ↔ N
M
Acceleration/deceleration Time
t = 2 π
60 ⋅ J M
⋅ 1
T
M
⋅
N
M
2 + N 2
B
2N
B
t =
 2 π
60
 2
⋅
J
M
1000 P
M
⋅
N
M
2 + N
B
2
2
N
M
: Operation speed (min −1 )
N B : Basic low speed (min −1 )
M
MAX
: Maximum speed (min −1 )
J
M
: Motor axis conversion inertial moment (kg ⋅ m2) (= Motor inertial moment + motor axis conversion load inertial moment)
T
M
: Motor maximum torque at basic low speed (N ⋅ m) (For a standard motor, max. torque = 30 min. rated torque x 1.2)
P
M
: Motor maximum output at basic low speed (kW) (For a standard motor, max. output = 30 min. rated output x 1.2)
Note: The values obtained from actual units may differe from calculated values due to mechanical losses, fluctuation in supply volt-
ages, mechanical noise, and measures taken for motor’s magnetic noise.
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