Mitsubishi Electric Melservo-J5 MR-J5 Series - Page 164

162
6 OPTIONS AND PERIPHERAL EQUIPMENT
6.2 Regenerative option
*1 Load torque converted into equivalent value on servo motor shaft TL can be calculated with the following formula.
T
L
= {(F
C
+ ( × W
L
× g)) × S} / (2000 ×  × )
*2 Load moment of inertia converted into equivalent value on servo motor shaft JL can be calculated with the following formula.
J
L
= J
L1
+ J
L2
+ J
L3
J
L1
is the load moment of inertia of the moving part, J
L2
is the load moment of inertia of the ball screw, and J
L3
is the load moment of
inertia of the coupling. J
L1
and J
L2
can be calculated with the following formulas.
J
L1
= W
L
× (S / (20 × ))
2
J
L2
= {( × 0.0078 × (L
B
/ 10)) / 32} × (D
B
/ 10)
4
From the calculation results in (1) to (8), find the absolute value (Es) of the sum total of negative energies.
■Losses of servo motor and servo amplifier in regenerative mode
The following table lists the efficiencies and other data of the servo motor and servo amplifier in the regenerative mode.
Inverse efficiency (
m
): Efficiency including some efficiencies of the servo motor and servo amplifier when rated (regenerative)
torque is generated at rated speed. Efficiency varies with the servo motor speed and generated torque. Because the
characteristics of the electrolytic capacitor change with time, allow inverse efficiency of approximately 10 % higher than those
shown above.
Capacitor charging (Ec): Energy charged into the electrolytic capacitor in the servo amplifier
Multiply the sum total of regenerative energies by the inverse efficiency, and subtract the capacitor charging from that result to
calculate the energy consumed by the regenerative option.
ER [J] = 
m
• E
s
- E
c
Select a regenerative option that meets the requirements of the system by calculating the power consumption of the
regenerative option based on a one-cycle operation period tf [s].
PR [W] = ER/tf
Regenerative
power
Torque T applied to servo motor [N•m]
*1*2
Energy E [J]
(1)
(2) T
2
= T
L
E
2
= 0.1047 • N • T
2
• t
1
(3)
(4), (8) T
4
, T
8
= 0 E
4
, E
8
= 0 (No regeneration)
(5)
(6) T
6
= T
L
E
6
= 0.1047 • N • T
6
• t
3
(7)
Servo amplifier Inverse efficiency [%] Capacitor charging [J]
MR-J5-10_ 70 9
MR-J5-20_ 85 9
MR-J5-40_ 90 11
MR-J5-60_ 90 11
MR-J5-70_ 90 18
MR-J5-100_ 90 18
MR-J5-200_ 90 36
MR-J5-350_ 90 40
MR-J5-500_ 90 45
MR-J5-700_ 90 70
(J
L
/ + J
M
) • N
9.55 • 10
4
t
psa1
1
•
T
1
=
+ T
L
2
0.1047
E
1
=
• N • T
1
• t
psa1
-(J
L
•  + J
M
) • N
9.55 • 10
4
t
psd1
1
•
T
3
=
+ T
L
2
0.1047
E
3
= • N • T
3
• t
psd1
(J
L
/ + J
M
) • N
9.55 • 10
4
t
psa2
1
•
T
5
=
+ T
L
2
0.1047
E
5
=
• N • T
5
• t
psa2
-(J
L
•  + J
M
) • N
9.55 • 10
4
t
psd2
1
•
T
7
=
+ T
L
2
0.1047
E
7
= • N • T
7
• t
psd2