sh030106u.pdf - 第334页

11. OPT ION S AND P ERI PHER AL EQU IPMENT 11 - 13 Formulas for calc ulatin g tor que and energy in opera tion Regenerative power Torque applied t o servo motor [N•m ] (Note 1, 2) Energy E [ J] 1) T 1 = 9.55 • 10 4 (J L …

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11. OPTIONS AND PERIPHERAL EQUIPMENT
11 - 12
11.2.2 Selection of regenerative option
A regenerative option for a horizontal axis can be selected with the rough calculation shown in this section.
To select a regenerative option precisely, use the capacity selection software.
(1) Rotary servo motor
(a) Regenerative energy calculation
Servo motor
Moving part
N
V
W
L
F
C
2)
1)
V
3)
4)
Forward
rotation
6)
5) 7)
Reverse
rotation
8)
Time
Feed speed of moving part
t
psa1 t1 tpsd1 t2 tpsa2 t3 t4tpsd2
V: Feed speed of moving part [mm/min]
N: Servo motor speed (N = V/ΔS) [r/min]
Δ
S: Travel distance per servo motor
revolution (ΔS = P
B
)
[mm/rev]
P
B
: Ball screw lead [mm]
L
B
: Ball screw length [mm]
D
B
: Ball screw diameter [mm]
W
L
: Moving part mass [kg]
F
C
: Load antidrag setting [N]
T
L
: Load torque converted into equivalent
value on servo motor shaft [N•m]
[N•m]
η: Drive system efficiency
µ: Friction coefficient
J
L
: Load moment of inertia converted into
equivalent value on servo motor shaft
[kg•cm
2
]
J
M
: Moment of inertia of the servo motor [kg•cm
2
]
π: Pi constant
g: Gravitational acceleration [m/s
2
]
11. OPTIONS AND PERIPHERAL EQUIPMENT
11 - 13
Formulas for calculating torque and energy in operation
Regenerative
power
Torque applied to servo motor [N•m]
(Note 1, 2)
Energy E [J]
1)
T
1
=
9.55 • 10
4
(J
L
/η+ J
M
) • N
•
t
psa1
1
+ T
L
E
1
=
2
0.1047
• N • T
1
• t
psa1
2) T
2
= T
L
E
2
= 0.1047 • N • T
2
• t
1
3)
T
3
=
9.55 • 10
4
-(J
L
• η+ J
M
) • N
•
t
psd1
1
+ T
L
E
3
=
2
0.1047
• N • T
3
• t
psd1
4), 8) T
4
, T
8
= 0 E
4
, E
8
= 0 (No regeneration)
5)
T
5
=
9.55 • 10
4
(J
L
/η+ J
M
) • N
•
t
psa2
1
+ T
L
E
5
=
2
0.1047
• N • T
5
• t
psa2
6) T
6
= T
L
E
6
= 0.1047 • N • T
6
• t
3
7)
T
7
=
9.55 • 10
4
-(J
L
• η+ J
M
) • N
•
t
psd2
1
+ T
L
E
7
=
2
0.1047
• N • T
7
• t
psd2
Note 1. Load torque converted into equivalent value on servo motor shaft T
L
can be calculated
with the following expression.
T
L
=
{(
F
C
+
(
µ× W
L
×
g))
×
Δ
S
}
/
(
2000 × π × η
)
2. Load moment of inertia converted into equivalent value on servo motor shaft J
L
can be
calculated with the following expression.
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 expressions.
J
L1
= W
L
× (ΔS/(20 × π))
2
J
L2
=
{(
π × 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.
11. OPTIONS AND PERIPHERAL EQUIPMENT
11 - 14
(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]
Servo amplifier
Inverse
efficiency [%]
Capacitor
charging [J]
MR-J4-10B(-RJ) 55 9 MR-J4-60B4(-RJ) 85 12
MR-J4-20B(-RJ) 75 9 MR-J4-100B4(-RJ) 85 12
MR-J4-40B(-RJ) 85 11 MR-J4-200B4(-RJ) 85 25
MR-J4-60B(-RJ) 85 11 MR-J4-350B4(-RJ) 85 43
MR-J4-70B(-RJ) 85 18 MR-J4-500B4(-RJ) 90 45
MR-J4-100B(-RJ) 85 18 MR-J4-700B4(-RJ) 90 70
MR-J4-200B(-RJ) 85 36 MR-J4-11KB4(-RJ) 90 120
MR-J4-350B(-RJ) 85 40 MR-J4-15KB4(-RJ) 90 170
MR-J4-500B(-RJ) 90 45 MR-J4-22KB4(-RJ) 90 250
MR-J4-700B(-RJ) 90 70 MR-J4-10B1(-RJ) 55 4
MR-J4-11KB(-RJ) 90 120 MR-J4-20B1(-RJ) 75 4
MR-J4-15KB(-RJ) 90 170 MR-J4-40B1(-RJ) 85 10
MR-J4-22KB(-RJ) 90 250
Inverse efficiency (η
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 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
Subtract the capacitor charging from the result of multiplying the sum total of regenerative energies
by the inverse efficiency to calculate the energy consumed by the regenerative option.
ER [J] = η
m
• Es - Ec
Calculate the power consumption of the regenerative option on the basis of single-cycle operation
period tf [s] to select the necessary regenerative option.
PR [W] = ER/tf