Yaskawa SGDS Sigma III Servo Amplifier - Manual (Page 321)

11 Appendix
11.1.3 Calculating the Required Capacity of Regenerative Resistors
11-6
• Required braking torque
• Effective torque
The above confirms that the provisionally selected servomotor and SERVOPACK capacities are sufficient. In the
next step, their performance in position control are checked.
(9) PG Feedback Pulse Dividing Ratio: Setting of Electronic Gear Ratio
As the electrical stop accuracy δ = ±0.01mm, take the position detection unit ∆ = 0.01mm/pulse.
(10) Reference Pulse Frequency
(11) Error Counter Pulses
Position loop gain Kp = 30 (1/
S
)
(12) Electrical Stop Accuracy
The above results confirm that the selected SERVOPACK and servomotor are applicable for the position control.
11.1.3 Calculating the Required Capacity of Regenerative Resistors
(1) Simple Calculation
When driving a servomotor with the horizontal axis, check the external regenerative resistor requirements using
the calculation method shown below.
(a) SERVOPACKs with Capacities of 400 W or Less
SERVOPACKs with capacities of 400 W or less do not have built-in regenerative resistors. The energy that
can be charged with capacitors is shown in the following table. If the rotational energy in the servomotor
exceeds these values, then connect a external regenerative resistor.
T = − T = − 0.139
60ta 60 × 0.1
2
π
N (J + J ) 2
π
× 3000 × (0.209 + 1.25) × 10
S
−4
M M L
L
0.319 (N m) < Instantaneous peak torque Satisfactory
T = =
t
Τ ta + T tc + T td
r m s
P L S
0.205 (N m) < Rated torque Satisfactory
2 2 2
1.5
(0.597) × 0.1 + (0.139) × 0.9 + (0.319) × 0.1 2 2 2
B
A
( )
× = × = 32768 × 4
k = =
P
∆
B
A
5
0.01
B
A
B
( )
B
A
32768 × 4
500
( )
vs = = = 25,000 (pps)
1000 × 15
60 × 0.01
1000V
60 × ∆
ε = = = 833 (pulse)
25,000
30
vs
Kp
− ∆ε = – = − − 0.17 < − 1 (pulse) = − 0.01 (pulse)
N
R
M
N
ε
(SERVOPACK
3000
3000
833
5000 ×
control range)
×