12 - 2
12. OPTIONS AND AUXILIARY EQUIPMENT
(b) To make selection according to regenerative energy
Use the following method when regeneration occurs continuously in vertical motion applications 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
Unbalance torque
T
F
T
U
Servo motor speed
Generated torque
Time
Up
No
tf(1 cycle)
Down
( )
(
)
(Driving)
(Regenerative)
T
psd2
t2 t3 t4t1
T
psa2
T
psd1
T
psa1
1)
2)
3)
4)
5)
6)
7)
8)
Formulas for calculating torque and energy in operation
Regenerative power Torque applied to servo motor [N
m] Energy [J]
1)
T
1
(J
L
J
M
)
9.55
10
4
No
1
T
psa1
T
U
T
F
E
1
2
0.1047
No
T
1
T
psa1
2)
T
2
T
U
T
F
E
2
0.1047 No T
2
t
1
3)
T
3
(J
L
J
M
)
9.55
10
4
No
1
T
psd1
T
U
T
F
E
3
2
0.1047
No
T
3
T
psd1
4), 8)
T
4
T
U
E
4
0 (No regeneration)
5)
T
5
(J
L
J
M
)
9.55
10
4
No
1
T
psa2
T
U
T
F
E
5
2
0.1047
No
T
5
T
psa2
6)
T
6
T
U
T
F
E
6
0.1047 No T
6
t
3
7)
T
7
(J
L
J
M
)
9.55
10
4
No
1
T
psd2
T
U
T
F
E
7
2
0.1047
No
T
7
T
psd2
Sum total of regenerative energies Sum total of negative energies in 1) to 8)
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 amplifier in
the regenerative mode.
Servo amplifier Inverse efficiency[%] Capacitor charging[J]
MR-J2S-10B(1) 55 9
MR-J2S-20B(1) 70 9
MR-J2S-40B(1) 85 11
MR-J2S-60B 85 11
MR-J2S-70B 80 18
MR-J2S-100B 80 18
MR-J2S-200B 85 40
MR-J2S-350B 85 40
MR-J2S-500B 90 45
MR-J2S-700B 90 70
Inverse efficiency ( ) :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%.
Capacitor charging (Ec) :Energy charged into the electrolytic capacitor in the servo amplifier.