sh030106u.pdf - 第335页

11. OPT ION S AND P ERI PHER AL EQU IPMENT 11 - 14 (b) Losses of serv o motor a nd s ervo amp lifier i n regener at ive m ode The followi ng table l ists the efficienci es and ot her data of th e s ervo mo tor and s ervo…

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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
11. OPTIONS AND PERIPHERAL EQUIPMENT
11 - 15
(2) Linear servo motor
(a) Thrust and energy calculation
Linear servo moto
r
secondary-side (magnet)
Load
V
M
1
M2
Linear servo motor
primary-side (coil)
Linear servo motor
F
t
2)
1)
V
3)
4)
Positive
direction
6)
5) 7)
Negative
direction
8)
Time
Feed speed
t
psa1 t1 tpsd1 t2 tpsa2 t3 t4tpsd2
The following shows equations of the linear servo motor thrust and energy at the driving pattern
above.
Section Thrust F of linear servo motor [N] Energy E [J]
1) F
1
= (M
1
+ M
2
) • V/t
psa1
+ F
t
E
1
= V/2 • F
1
• t
psa1
2) F
2
= F
1
E
2
= V • F
2
• t
1
3) F
3
= -(M
1
+ M
2
) • V/t
psd1
+ F
t
E
3
= V/2 • F
3
• t
psd1
4), 8) F
4,
F
8
= 0 E
4
, E
8
= 0 (No regeneration)
5) F
5
= (M
1
+ M
2
) • V/t
psa2
+ F
t
E
5
= V/2 • F
5
• t
psa2
6) F
6
= F
t
E
6
= V • F
6
• t
3
7) F
7
= -(M
1
+ M
2
) • V/t
psd2
+ F
t
E
7
= V/2 • F
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
For inverse efficiency and capacitor charging energy, refer to (1) (b) in this section.
(c) Regenerative energy calculation
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 resistor.
ER [J] = η • Es - Ec
From the total of ER's whose subtraction results are positive and one-cycle period, the power
consumption PR [W] of the regenerative option can be calculated with the following equation.
PR [W] = total of positive ER's/one-cycle operation period (tf)
Select a regenerative option from the PR value. Regenerative option is not required when the energy
consumption is equal to or less than the built-in regenerative energy.