Specifications
6– 25
6
6. OPTIONS AND AUXILIARY EQUIPMENT
6-2-7 Leakage current breaker
120
100
80
60
40
20
0
2 3.5 5.5 8 14 22 38 80 150
30 60 100
Fig. 6-1 Leakage Current Example
(Ig1, Ig2) for CV Cable Run
in Metal Conduit
Table 6-1 Servo Motor's Leakage
Current Example (Igm)
Servo Motor
Output [kW]
0.05 to 0.5
0.6 to 1.0
1.2 to 2.2
3 • 3.5
Leakage
Current [mA]
0.1
0.1
0.2
0.3
Cable size[mm
2
]
[mA]
Table 6-2 Servo Amplifier's
Leakage Current
Example (Iga)
Servo Amplifier
Capacity [kW]
0.1 to 0.6
0.7 to 3.5
Leakage
Current [mA]
0.1
0.15
Table 6-3 Leakage Circuit Breaker
Selection Example
Servo
Amplifier
MR – J2 – 10A
to
MR – J2 – 350A
MR – J2 – 10A1
to
MR – J2 – 40A1
Rated Sensitivity
Current of Leakage
Circuit Breaker
15 [mA]
Leakage current
(1) Selection method
High-frequency chopper currents controlled by pulse width modulation flow in the AC servo cir-
cuits. 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 ampli-
fier, 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]
…
(6-2)
Ig1: Leakage current on the electric channel from the leakage current breaker to the input
terminals of the servo amplifier (Found from Fig. 6-1.)
Ig2: Leakage current on the electric channel from the output terminals of the servo amplifier to
the servo motor (Found from Fig. 6-1.)
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 6-2.)
Igm: Leakage current of the servo motor (Found from Table 6-1.)
SM
Servo
amplifier
Noise
filter
NV
Ig1 Ign Iga Ig2 Igm
K: Constant considering the harmonic contents
Leakage current breaker
Type
Mitsubishi
products
NV – SF
NV – CF
NV – CA
NV – CS
NV – SS
Models provided with
harmonic and surge
reduction techniques
General
models
K
1
3
Cable
Cable