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6. OPTIONS AND AUXILIARY EQUIPMENT
2) To make selection according to regenerative energy
Use the following method when regeneration occurs continuously in vertical motion applica-
tions or when it is desired to make an in-depth selection of the regenerative brake option:
a. Regenerative energy calculation
Use the following table to calculate the regenerative energy.
M
Friction
torque
T
F
tf(1 cycle)
No
Up
t
t
1
T
T
psa
psd
q
1
1
( + )
(Driving)
w
r
e
(Regenerative)
( - )
b. 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 am-
plifier in the regenerative mode.
Servo Amplifier
MR–J2–10A(1)
MR–J2–20A(1)
MR–J2–40A(1)
MR–J2–60A
MR–J2–70A
MR–J2–100A
MR–J2–200A
MR–J2–350A
Inverse efficiency (η)
Capacitor charging (Ec) : Energy charged into the electrolytic capacitor in the servo amplifier.
Subtract the capacitor charging from the result of multiplying the sum total of regenerative ener-
gies by the inverse efficiency to calculate the energy consumed by the regenerative brake option.
Calculate the power consumption of the regenerative brake option on the basis of single-cycle
operation period tf [s] to select the necessary regenerative brake option.
Formulas for Calculating Torque and Energy in Operation
Regenerative
Power
1)
2)
T
U
3)
4), 8)
Time
Down
5)
t
t
2
3
4
T
T
psa
psd
2
2
6)
i
t
7)
y
Sum total of regenerative energies
u
Inverse Efficiency[%]
Capacitor Charging[J]
55
9
70
9
85
11
85
11
80
18
80
18
85
40
85
40
: Efficiency including some efficiencies of the servo motor and servo
amplifier when rated (regenerative) torque is generated at rated speed.
Since the efficiency varies with the speed and generated torque, allow
for about 10%.
[J] = η • Es–Ec
E
R
P
[W] = E
/tf ...................................................................................... (6-1)
R
R
6– 3
Torque applied to servo motor [N • m]
(J
+ J
)•No
1
L
M
T
=
•
+ T
1
4
9.55 x 10
T
Psa1
T
= T
+ T
2
U
F
(J
+ J
)•No
1
L
M
T
=
•
+ T
3
4
9.55 x 10
T
Psd1
T
= T
4
U
(J
+ J
)•No
1
L
M
T
=
•
- T
5
4
9.55 x 10
T
Psa2
T
= T
+ T
6
U
F
(J
+ J
)•No
1
L
M
T
=
•
- T
7
4
9.55 x 10
T
Psd2
Sum total of negative energies in 1) to 8)
Energy [J]
0.1047
+ T
E
=
•No•T
•T
U
F
1
1
2
E
= 0.1047•No•T
•t
2
2
1
0.1047
+ T
E
=
•No•T
•T
U
F
3
3
2
E
0 (Not regenerative)
4
0.1047
+ T
E
=
•No•T
•T
U
F
5
5
2
E
= 0.1047•No•T
•t
6
6
3
0.1047
+ T
E
=
•No•T
•T
U
F
7
7
2
Psa1
Psd1
Psa2
Psd2
6
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