Hitachi Vector Control with the SJ300 Inverter

2
max
2
2
max1
L
N4
VW
J
⋅⋅
⋅
=
π
Appendix A Calculation of total inertia (reflected to the motor shaft)
(A-1) Ventilation Fan
s Inertia of a motor = J
M
[kgm
2
]
s Inertia of a fan = J
L
[kgm
2
] : Contact a fan manufacturer for the J
L
value.
Total inertia Σ J = J
M
+ J
L
(Note) If there is a pulley inbetween them, calculation will be as follows.
Inertia Rotation Converted Inertia
Motor J
M
N
1
J
M
Pulley 1
J
1
N
1
J
1
Pulley 2 J
2
N
2
Fan J
L
N
2
Total - -
(A-2) Truck
s Maximum speed = V
max
[m/min]
s Maximum motor rotation = N
max
[rpm]
s Inertia of a gear box = J
G
[kgm
2
] (*)
s Inertia of mechanics = J
m
[kgm
2
] (*)
s Inertia of a motor = J
M
[kgm
2
] (*)
s Inertia of the load = J
L
[kgm
2
]
(*) Contact each manufacturer for each
J [kgm
2
] value.
Total inertia Σ J = J
G
+ J
m
+ J
M
+ J
L
Ÿ [kgm
2
]
W
1
= W
2
+ W
3
[kg] : Total weight
Refer to Appendix B for calculation of load inertia.
Pulley 1
Rotation = N
1
[rpm]
Inertia J
1
[kgm2]
Pulley 2
Rotation = N
2
[rpm]
Inertia J
2
[kgm2]
Ventilation fan
Inertia J
L
[kgm2]
Motor
Rotation = N
1
[rpm]
Inertia J
M
[kgm2]
2
1
2
2
N
N
J








⋅
2
1
2
L
N
N
J








⋅
2
1
2
L
2
1
2
2M1
N
N
J
N
N
JJJ








⋅+








⋅++
Gear box
J
G
[kgm
2
]
M B
Motor
J
M
[kgm
2
]
N
max
[rpm]
Brake
J
B
[kgm
2
]
Material
Ÿ W
3
[kg] : Possible max. weight
Mechanics
J
m
[kgm
2
]
Truck : W
2
[kg]
V
max
[m/min]
: Max. speed