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11 - 83 11. OPTIONS AND AUXILI ARY EQUIPMENT 11.18 Leakage current bre a ker (1) Selection method High-frequency chopper currents controlled by puls e widt h modulation flow in the AC se rvo circuits. Leakage currents co…

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11 - 82
11. OPTIONS AND AUXILIARY EQUIPMENT
(f) Varistors for input power supply (Recommended)
Varistors are effective to prevent exogenous noise and lightning surge from entering the servo amplifier.
When using a varistor, connect it between each phase of the input power supply of the equipment. For
varistors, the TND20V-431K, TND20V-471K and TND20V-102K, manufactured by NIPPON CHEMI-
CON, are recommended. For detailed specification and usage of the varistors, refer to the manufacturer
catalog.
Power
supply
voltage
Varistor
Maximum rating
Maximum limit
voltage
Static
capacity
(reference
value)
Varistor voltage
rating (range)
V1mA
Permissible circuit
voltage
Surge current
immunity
Energy
immunity
Rated
pulse
power
AC[Vrms] DC[V] 8/20 s[A] 2ms[J] [W] [A] [V] [pF] [V]
100V class TND20V-431K 275 350 10000/1 time 195
1.0 100
710 1300 430(387 to 473)
200V class TND20V-471K 300 385 7000/2 time 215 775 1200 470(423 to 517)
400V class TND20V-102K 625 825
7500/1 time
6500/2 time
400 1650 500 1000(900 to 1100)
[Unit: mm]
d
W E
H
D
L
T
Model
D
Max.
H
Max.
T
Max.
E
1.0
(Note)L
min.
d
0.05
W
1.0
TND20V-431K
21.5 24.5
6.4 3.3
TND20V-471K 6.6 3.5 20 0.8 10.0
TND20V-102K 22.5 25.5 9.5 6.4
Note. For special purpose items for lead length (L), contact the manufacturer.
11 - 83
11. OPTIONS AND AUXILIARY EQUIPMENT
11.18 Leakage current breaker
(1) Selection method
High-frequency chopper currents controlled by pulse width modulation flow in the AC servo circuits.
Leakage currents containing harmonic contents are larger than those of the motor which is run with a
commercial power supply.
Select a leakage current breaker according to the following formula, and ground the servo amplifier, servo
motor, etc. securely.
Make the input and output cables as short as possible, and also make the grounding cable as long as
possible (about 30cm) to minimize leakage currents.
Rated sensitivity current
10 {Ig1 Ign Iga K (Ig2 Igm)} [mA] (11.1)
M
Servo
amplifier
Noise
filter
NV
I
g
1I
g
nI
g
aI
g
2I
g
m
Cable
Cable
K: Constant considering the harmonic contents
Leakage current breaker
K
Type
Mitsubishi
products
Models provided with
harmonic and surge
reduction techniques
NV-SP
NV-SW
NV-CP
NV-CW
NV-L
1
General models
BV-C1
NFB
NV-L
3
Ig1: Leakage current on the electric channel from the leakage current breaker to the input terminals of the
servo amplifier (Found from Fig. 11.3.)
Ig2: Leakage current on the electric channel from the output terminals of the servo amplifier to the
servo motor (Found from Fig. 11.3.)
Ign: Leakage current when a filter is connected to the input side (4.4mA per one FR-BIF(-H))
Iga: Leakage current of the servo amplifier (Found from Table 11.5.)
Igm: Leakage current of the servo motor (Found from Table 11.4.)
120
100
80
60
40
20
0
23.5
5.5
814223880150
30 60 100
Cable size[mm
2
]
[mA]
L
e
a
k
a
g
e
c
u
r
r
e
n
t
120
100
80
60
40
20
0
2
3.5
5.5
8
14
22
38
80
150
30
60
100
Cable size[mm
2
]
[mA]
L
e
a
k
a
g
e
c
u
r
r
e
n
t
a. 200V class
b. 400V class
Fig. 11.3 Leakage current example (lg1, lg2) for CV cable run in metal conduit
11 - 84
11. OPTIONS AND AUXILIARY EQUIPMENT
Table 11.4 Servo motor's leakage current example (Igm) Table 11.5 Servo amplifier's leakage current example (Iga)
Servo motor power
[kW]
Leakage current
[mA]
Servo amplifier capacity
[kW]
Leakage current
[mA]
0.05 to 1 0.1
0.1 to 0.6 0.1
2 0.2
0.75 to 3.5 (Note) 0.15
3.5 0.3
5 7 2
5 0.5
11 15 5.5
7 0.7
22 7
11 1.0
Note. For the 3.5kW of 400V class, leakage current is 2mA,
which is the same as for 5kW and 7kW.
15 1.3
22 2.3
Table 11.6 Leakage circuit breaker selection example
Servo amplifier
Rated sensitivity current of leakage
circuit breaker [mA]
MR-J3-10B to MR-J3-350B
MR-J3-10B1 to MR-J3-40B1
MR-J3-60B4 to MR-J3-350B4
15
MR-J3-500B(4) 30
MR-J3-700B(4) 50
MR-J3-11KB(4) to MR-J3-22KB(4) 100
(2) Selection example
Indicated below is an example of selecting a leakage current breaker under the following conditions.
M
NV
Ig1 Iga Ig2 Igm
Servo
amplifier
MR-J3-40B
2mm
2
5m 2mm
2
5m
Servo motor
HF-KP43
Use a leakage current breaker generally available.
Find the terms of Equation (11.1) from the diagram.
Ig1
20
1000
5
0.1
[mA]
Ig2
20
1000
5
0.1
[mA]
Ign
0 (not used)
Iga
0.1 [mA]
Igm
0.1 [mA]
Insert these values in Equation (11.1).
Ig
10 {0.1 0 0.1 1 (0.1 0.1)}
4.0 [mA]
According to the result of calculation, use a leakage current breaker having the rated sensitivity current (Ig)
of 4.0[mA] or more. A leakage current breaker having Ig of 15[mA] is used with the NV-SP/SW/CP/CW/HW
series.