Earth-Leakage Current Breaker - Mitsubishi Electric MELSERVO-J3W Series Instruction Manual

11. OPTIONS AND AUXILIARY EQUIPMENT

11.10 Earth-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 an earth-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 (A-axis) Igm (A-axis) Ig2 (B-axis) Igm (B-axis))} [mA]· · (11.1)
MCCB
Ig1 : Leakage current on the electric channel from the earth-leakage current breaker to the input terminals
of the servo amplifier (Found from Fig. 11.1.)
Ig2 : Leakage current on the electric channel from the output terminals of the servo amplifier to the servo
motor (Found from Fig. 11.1.)
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 11.4.)
Igm : Leakage current of the servo motor (Found from Table 11.3.)
Cable
Cable
Noise filter
Servo
amplifier
Cable
Ig1 Ign Iga
120
100
80
60
40
[mA]
20
0
2 3.5 8 1422 38 80 150
5.5
Cable size [mm
a. 200V class
Fig. 11.1 Leakage current example (lg1, lg2) for CV cable run in metal conduit
A-axis
M
Ig2 Igm
B-axis
M
Ig2 Igm
30 60 100
]
2
11 - 49
Earth-leakage current breaker
Mitsubishi
Type
products
NV-SP
Models provided with NV-SW
harmonic and surge NV-CP
reduction techniques NV-CW
General models
120
100
80
60
40
[mA]
20
0
2
Cable size [mm
K
1
NV-L
BV-C1
NFB 3
NV-L
5.5 14 38 100
3.5 8 22 60 150
30 80
]
2
b. 400V class