Mitsubishi Electric MR-J5 Series User Manual page 140

Regenerative Torque applied to servo motor [N•m]
power
1)
T
1
2) T
2
3)
T
3
4), 8) T , T
4
5)
T
5
6) T
6
7)
T
7
*1 Load torque converted into equivalent value on servo motor shaft TL can be calculated with the following formula.
T = {(F + (μ × W
L C
*2 Load moment of inertia converted into equivalent value on servo motor shaft JL can be calculated with the following formula.
J = J + J + J
L L1 L2 L3
J is the load moment of inertia of the moving part, J
L1
inertia of the coupling.
J and J can be calculated with the following formulas. J
L1 L2
J = {(π × 0.0078 × (L
L2
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.
Servo amplifier
MR-J5-10_
MR-J5-20_
MR-J5-40_
MR-J5-60_
MR-J5-70_
MR-J5-100_
MR-J5-200_
MR-J5-350_
Inverse efficiency (η
m
torque is generated at rated speed. Efficiency varies with the servo motor speed and generated torque. Since the
characteristics of the electrolytic capacitor change with time, allow for approximately 10 % higher inverse efficiency.
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] = η • E - E
m s c
Select a necessary regenerative option by calculating the power consumption of the regenerative option based on a one-cycle
operation period tf [s].
PR [W] = ER/tf
6 OPTIONS AND PERIPHERAL EQUIPMENT
138
6.2 Regenerative option
(J /η + J ) • N 1
L M
•
+ T
=
L
4
9.55 • 10 t
psa1
= T
L
-(J • η + J ) • N 1
L M
• + T
=
L
4
9.55 • 10 t
psd1
= 0
8
(J /η + J ) • N 1
L M
• + T
=
L
4
9.55 • 10 t
psa2
= T
L
-(J • η + J ) • N 1
L M
• + T
=
L
4
9.55 • 10 t
psd2
× g)) × ΔS} / (2000 × π × η)
L
4
/ 10)) / 32} × (D / 10)
B B
): Efficiency including some efficiencies of the servo motor and servo amplifier when rated (regenerative)
*1*2
Energy E [J]
0.1047
E =
1
E = 0.1047 • N • T
2
0.1047
E =
3
E , E = 0 (No regeneration)
4 8
0.1047
E =
5
E = 0.1047 • N • T
6
0.1047
E =
7
is the load moment of inertia of the ball screw, and J
L2
= W × (ΔS / (20 × π))
L1 L
Inverse efficiency [%]
70
85
90
90
90
90
90
90
• N • T • t
1 psa1
2
• t
2 1
• N • T • t
3 psd1
2
• N • T • t
5 psa2
2
• t
6 3
• N • T • t
7 psd2
2
is the load moment of
L3
2
Capacitor charging [J]
9
9
11
11
18
18
36
40