Earth-Leakage Current Breaker - Mitsubishi Electric MR-J4W2 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.
To minimize leakage currents, make the input and output cables as short as possible, and make the
grounding cable longer than 30 cm.
Rated sensitivity current ≥ 10 • {Ig1 + Ign + Iga + K • (Ig2 (A-axis) + Igm (A-axis) + Ig2 (B-axis) + Igm
Ig1 : Leakage current on the electric channel from the earth-leakage current breaker to the input
Ig2 terminals of the servo amplifier (Found from Fig. 11.1.)
Ign : Leakage current on the electric channel from the output terminals of the servo amplifier to the
Iga servo motor (Found from Fig. 11.1.)
Igm : Leakage current when a filter is connected to the input side (4.4 mA per one FR-BIF)
: Leakage current of the servo amplifier (Found from table 11.3.)
: Leakage current of the servo motor (Found from table 11.2.)
Fig. 11.1 Leakage current example (lg1, lg2) for CV cable run in metal conduit
Cable
NV
Noise filter
Servo
amplifier
Ig1 Ign Iga
120
100
80
60
40
20
0
2
3.5 8
Cable size [mm ]
Table 11.2 Servo motor's leakage current example (lgm)
Servo motor power [kW]
(B-axis) + Ig2 (C-axis) + Igm (C-axis))} [mA].........(11.1)
Cable
Earth-leakage current breaker
M A-axis
Ig2 Igm
Cable
Models provided with
B-axis
M
harmonic and surge
reduction techniques
Ig2 Igm
Cable
C-axis
M
General models
Ig2 Igm
5.5 14 38100
22 60 150
30 80
2
0.05 to 1
11 - 41
Mitsubishi
Type
products
NV-SP
NV-SW
NV-CP
NV-CW
NV-HW
BV-C1
NFB
NV-L
Leakage current [mA]
0.1
K
1
3