Calculating Start And Stop Times - YASKAWA VS-626M5 Instruction Manual

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.
Item
Motor Characteristics
Fixed Torque Characteristics
(0 ≦ N ≦ N )
M B
0 ↔ N Acceleration/deceleration Time
M
Fixed Output Characteristics
(N ≦ N ≦ N )
B M MAX
N ↔ N Acceleration/deceleration Time
B M
Fixed Torque + Fixed Output Characteris-
tics
(N ≦ N ≦ N )
B M MAX
0 ↔ N Acceleration/deceleration Time
M
−1
N : Operation speed (min )
M
−1
N : Basic low speed (min )
B
−1
M : Maximum speed (min
MAX
J : Motor axis conversion inertial moment (kg
M
T : Motor maximum torque at basic low speed (N
M
P : Motor maximum output at basic low speed (kW) (For a standard motor, max. output = 30 min. rated output x 1.2)
M
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.
Table 15.6 Formulas for Calculating Start and Stop Times
Calculating from Torque
Torque (NSm)
T
M
0 N
B
Fixed
torque
t = 2 π
⋅ J ⋅ N
M
60
t = 2 π
⋅ 1
⋅ J
M
60 T
t = 2 π ⋅ 1
⋅ J
M
60 T
)
⋅
m2) (= Motor inertial moment + motor axis conversion load inertial moment)
⋅
m) (For a standard motor, max. torque = 30 min. rated torque x 1.2)
15 -17
P
M
Motor
speed
N
MAX
−1
(min )
Fixed
output
⋅ 1
t =
M
T
M
N 2 –N 2
M
B
t =
⋅
2N
M B
2 2
N + N
M
B
t =
⋅
2N
M B
15.3 Determining Drive Capacity
Calculating from Output
Output (kW)
Motor
speed
0 N N
B MAX
(min
Fixed
Fixed
torque
output
2
J
 
2 π
M
⋅ N ⋅ N
⋅
B M
60 1000 P
M
2
2 2
  J N –N
2 π
M M B
⋅ ⋅
1000 P 2
60
M
2
2 2
  J N + N
2 π
M M B
⋅ ⋅
60 1000 P 2
M
−1
)
15