Leakage Current Breaker - Mitsubishi Electric MR-J2S-CP Instruction Manual

14. OPTIONS AND AUXILIARY EQUIPMENT

14.2.7 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] ..........(14.1)
Cable
Noise
NV
filter
Ig1 Ign
Ig1: Leakage current on the electric channel from the leakage current breaker to the input terminals
of the servo amplifier (Found from Fig. 14.1.)
Ig2: Leakage current on the electric channel from the output terminals of the servo amplifier to the
servo motor (Found from Fig. 14.1.)
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 14.5.)
Igm: Leakage current of the servo motor (Found from Table 14.4.)
120
100
80
60
40
[mA]
20
0
2 3.5 8 1422 38 80 150
5.5
Cable size[mm
Fig. 14.1 Leakage current example
(Ig1, Ig2) for CV cable run
in metal conduit
Servo Cable
amplifier
Iga Ig2
Table 14.4 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
]
2
K: Constant considering the harmonic contents
Leakage current breaker
Type
M Models provided with
harmonic and surge
reduction techniques
Igm
General models
leakage current
example (Igm)
Leakage Servo amplifier
current [mA] capacity [kW]
0.1 0.1 to 0.6
0.1 0.7 to 3.5
0.2
0.3
0.5
0.7
Table 14.6 Leakage circuit breaker selection example
MR-J2S-10CP to MR-J2S-350CP
MR-J2S-10CP1 to MR-J2S-40CP1
MR-J2S-500CP
MR-J2S-700CP
14 - 45
Mitsubishi products
NV-SP
NV-SW
NV-CP
NV-CW
NV-HW
BV-C1
NFB
NV-L
Table 14.5 Servo amplifier's
leakage current
example (Iga)
Leakage
current [mA]
0.1
0.15
5 7 2
Servo amplifier
circuit breaker [mA]
K
1
3
Rated sensitivity
current of leakage
15
30
50