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12. OPTIONS AND AUXILIARY EQUIPMENT
12.2.8 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 (11.8 in)) to minimize leakage currents.
Rated sensitivity current 10 {Ig1 Ign Iga K (Ig2 Igm)} [mA] ..........(12.2)
Cable
NV
Ig1:
Leakage current on the electric channel from the leakage current breaker to the input terminals
of the servo amplifier (Found from Fig. 12.1.)
Ig2:
Leakage current on the electric channel from the output terminals of the servo amplifier to the
servo motor (Found from Fig. 12.1.)
Ign:
Leakage current when a filter is connected to the input side (4.4mA per one FR-BIF)
Iga:
Leakage current of the servo amplifier (Found from Table 12.5.)
Igm:
Leakage current of the servo motor (Found from Table 12.4.)
120
100
80
60
40
[mA]
20
0
2 3.5
8 1422 38 80 150
5.5
Cable size[mm
Fig. 12.1 Leakage current example
(Ig1, Ig2) for CV cable run
in metal conduit
Noise
filter
Servo
amplifier
Ig1 Ign
Iga
Table 12.4 Servo motor's
Servo motor
output [kW]
0.05 to 0.5
0.6 to 1.0
1.2 to 2.2
3 to 3.5
5
7
30 60 100
11
2
]
15
22
Cable
M
Ig2
Igm
leakage current
example (Igm)
Leakage
current [mA]
0.1
0.1
0.2
0.3
0.5
0.7
1.0
1.3
2.3
12 - 52
K: Constant considering the harmonic contents
Leakage current breaker
Mitsubishi
Type
Models provided with
harmonic and surge
reduction techniques
General models
Table 12.5 Servo amplifier's
leakage current
example (Iga)
Servo amplifier
Leakage current
capacity [kW]
[mA]
0.1 to 0.6
0.1
0.7 to 3.5
0.15
5 7
2
11 15
5.5
22
7
Table 12.6 Leakage circuit breaker selection example
Servo amplifier
MR-J2S-10B to MR-J2S-350B
MR-J2S-10B1 to MR-J2S-40B1
MR-J2S-500B
MR-J2S-700B
MR-J2S-11KB to MR-J2S-22KB
K
products
NV-SP
NV-SW
NV-CP
1
NV-CW
NV-L
BV-C1
NFB
3
NV-L
Rated sensitivity
current of leakage
circuit breaker [mA]
15
30
50
100
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