Leakage Current Breaker - Mitsubishi Electric MELSERVO MR-J2-A Product Specifications And Installation Manual

6. OPTIONS AND AUXILIARY EQUIPMENT

6-2-7 Leakage current breaker

(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)
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. 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.)
120
100
80
60
[mA]
40
20
0
2 3.5 5.5 8 14 22 38 80 150
Cable size[mm
Fig. 6-1 Leakage Current Example
(Ig1, Ig2) for CV Cable Run
in Metal Conduit
Cable
Servo
SM
amplifier
Iga Ig2 Igm
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
30 60 100
2
]
6– 25
K: Constant considering the harmonic contents
Leakage current breaker
Mitsubishi
Type
Models provided with
harmonic and surge
reduction techniques
General
models
Table 6-2 Servo Amplifier's
Leakage Servo Amplifier
Current [mA] Capacity [kW]
0.1
0.1 to 0.6
0.1
0.2
0.7 to 3.5
0.3
Table 6-3 Leakage Circuit Breaker
Servo
Amplifier
MR – J2 – 10A
to
MR – J2 – 350A
MR – J2 – 10A1
to
MR – J2 – 40A1
K
products
NV – SF
1
NV – CF
NV – CA
3
NV – CS
NV – SS
Leakage Current
Example (Iga)
Leakage
Current [mA]
0.1
0.15
Selection Example
Rated Sensitivity
Current of Leakage
Circuit Breaker
15 [mA]
6