WEIHONG WISE WSDV-5R020PSB - Page 29

Specialized Concentrated Focused
Servo Motor「23」
Shape
Formula for J
Shape
Formula for J
a
b
R
Conveyor
W
D
22
1
[]
4
J WD kg m
W:Mass[kg]
D:Diameter of the
wheel [m]
J without the wheel
Ball screw
w
P
F
2
2
1
2
[]
4 


WP
J J kg m
W:Mass [kg]
P:Rail travel [m]
J
1
:J of ball screw [kg•m
2
]
If you don’t know the mass [kg], calculate according to the following formula.
Mass W[kg]=Density ρ[kg/m
3
]

Volume V[m
3
]
Here are density references of some typical substances.
Iron ρ=7.9

10
3
[kg/m
3
] Aluminum ρ=2.8

10
3
[kg/m
3
] Brass ρ=8.5

10
3
[kg/m
3
]
3.5.1.4 Calculate the Torque
1) Peak torque
Peak torque refers to the max. torque required in running, mainly in acceleration and deceleration
stages.
The value is approximate 80% less of the max. torque of the motor. If the value is negative, a
regenerative resistor may be needed.
t
psa
t
psd
Nofo
Command
pulse
frequency
f
[pps]
Motor
speed
[r/min]
Time
Acc. torque T
a
Dec. torque
T
d
Time
Command
Motor
speed
Fig. 3-6 Illustration of peak torque