MITSUBISHI ELECTRIC MR-E- A/AG - Manual (Page 177)

13 - 2
13. 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
Unbal
ance t
o
rque
T F
T U
S
e
rv
o m
o
to
r s
peed
Gen
e
rat
ed t
o
rque
Time
Up
No
tf(1 cycle)
Down
( )
( )
(Driving)
(Regenerative)
T psd2
t2 t3 t4 t1
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
N 0
1
T
psa1
T U T F
E
1
2
0.1047
N 0 T 1 T psa1
2) T
2
T
U
T
F
E
2
0.1047 N
0
T
2
t
1
3) T 3
(J L J M )
9.55 10 4
N 0
1
T psd1
T U T F E
3
2
0.1047
N
0
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
N 0
1
T psa2
T
U
T
F
E 5
2
0.1047
N 0 T 5 T psa2
6) T
6
T
U
T
F
E
6
0.1047 N
0
T
6
t
3
7) T
7
(J L J M )
9.55 10 4
N
0
1
T psd2
T U T F
E 7
2
0.1047
N 0 T 7 T psd2
From the calculation results in 1) to 8), find the absolute value (Es) of the sum total of negative
energies.
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-E-10A(1) 55 9
MR-E-20A(1) 70 9
MR-E-40A(1) 85 11
MR-E-70A 80 18
MR-E-100A 80 18
MR-E-200A 85 40
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 torque, allow for about 10%.
Capacitor charging (Ec) :Energy charged into the electrolytic capacitor in the servo amplifier.