Leakage Current Breaker - Mitsubishi Electric MELSERVO-J2-Super Series Instruction Manual

15. OPTIONS AND AUXILIARY EQUIPMENT

15.2.7 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] ..........(15.2)
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. 15.1.)
Ig2: Leakage current on the electric channel from the output terminals of the servo amplifier to the
servo motor (Found from Fig. 15.1.)
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 15.5.)
Igm: Leakage current of the servo motor (Found from Table 15.4.)
120
100
80
60
40
[mA]
20
0
2 3.5 8 1422 38 80 150
5.5
Cable size[mm
Fig. 15.1 Leakage current example
(Ig1, Ig2) for CV cable run
in metal conduit
Servo Cable
amplifier
Iga Ig2
Table 15.4 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
Models provided with
SM
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 15.6 Leakage circuit breaker selection example
MR-J2S-10CP-S084 to
MR-J2S-350CP-S084
MR-J2S-10CP1-S084 to
MR-J2S-40CP1-S084
MR-J2S-500CP-S084
MR-J2S-700CP-S084
15 - 34
Mitsubishi products
NV-SP
NV-SW
NV-CP
NV-CW
NV-HW
BV-C1
NFB
NV-L
Table 15.5 Servo amplifier's
leakage current
example (Iga)
Leakage
current [mA]
0.1
0.15
5 7 2
Servo amplifier
K
1
3
Rated sensitivity
current of leakage
circuit breaker [mA]
15
30
50