SERIES

Appendices
Capacity Selection for Servomotors
Capacity Selection Example for Direct Drive Servomotors
1. Mechanical Specifications
D T
Item Code Value Item Code Value
Turntable
Servomotor
Turntable Mass W 12 kg
Turntable
Diameter
Rotational Angle
per Cycle
D T
300 mm
Acceleration/
Deceleration
Time
Operating
Frequency
t p
= t psa
= t psd
0.1 s
t f
2 s
θ 270 deg Load Torque T L 0 N•m
Positioning Time t 0 0.35 s Settling Time t s 0.1 s
2. Motor Speed of Direct Drive Servomotor
θ 60 270 60
N O
= × = × = 300 (min -1 )
360 (t 0 - t p - t s ) 360 (0.35 - 0.1 - 0.1)
3. Operation Pattern
Motor speed (min -1 )
300
0.1 0.1 0.1
t psd t s
Time (s)
t psa
8
t s
0.35
t 0
2.0
One cycle (t f )
4. Load Moment of Inertia
1 2
J
1
L = × D T × W = × (300 × 10 -3 ) 2 × 12 = 0.135 (kgm 2 )
8
5. Load Acceleration/Deceleration Torque
N
T a = J L × 2π × O /60
= 0.135 × 2π ×
300/60
= 42.4 (Nm)
t p 0.1
6. Provisional Selection of Direct Drive Servomotor
Selection Conditions
• Load acceleration/deceleration torque < Instantaneous maximum torque of Direct Drive
Servomotor
• Load moment of inertia < Allowable load moment of inertia ratio (J R ) × Moment of inertia of
Direct Drive Servomotor (J M )
The following Servomotor meets the selection conditions.
• SGMCV-17CEA11
Specifications of the Provisionally Selected Servomotor
Capacity Selection for Servomotors
Item
Value
Rated Torque
17 (N•m)
Instantaneous Maximum Torque
51 (N•m)
Moment of Inertia (J M ) 0.00785 (kg•m 2 )
Allowable Load Moment of Inertia Ratio (J R ) 25
455