Leakage Current Breaker - Mitsubishi Electric MELSERVO-J2 Series 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] ..........(14.2)
Cable
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 14.6.)
Igm: Leakage current of the servo motor (Found from Table 14.5.)
120
100
80
60
40
[mA]
20
0
Fig. 14.1 Leakage Current Example
(Ig1, Ig2) for CV Cable Run
in Metal Conduit
Downloaded from ManualsNet.com
Noise
NV
filter
Servo
amplifier
Ig1 Ign Iga
2 3.5 8 1422 38 80 150
5.5 30 60 100
Cable size[mm ]
2
search engine
K: Constant considering the harmonic contents
Cable
SM
Models provided with
harmonic and surge
reduction techniques
Ig2 Igm
General models
Table 14.5 Servo Motor's Leakage
Current Example (Igm)
Servo Motor Leakage
Output [kW] Current [mA]
0.05 to 0.5 0.1
0.6 to 1.0 0.1
1.2 to 2.2 0.2
3 to 3.5 0.3
14 - 31
Leakage current breaker
Mitsubishi
Type
products
NV-SP
NV-SW
NV-CP
NV-CW
NV-L
BV-C1
NFB
NV-L
Table 14.6 Servo Amplifier's Leakage
Current Example (Iga)
Servo Amplifier Leakage
Capacity [kW] Current [mA]
0.1 to 0.6
0.7 to 3.5
Table 14.7 Leakage Circuit Breaker
Selection Example
Rated Sensitivity
Servo Amplifier Current of Leakage
Circuit Breaker
MR-J2-10C
to 15 [mA]
MR-J2-350C
K
1
3
0.1
0.15