Mitsubishi Electric MR-E A Series Instruction Manual page 205

13. OPTIONS AND AUXILIARY EQUIPMENT
13.2.7 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.
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Rated sensitivity current 10 {Ig1 Ign Iga K (Ig2 Igm)} [mA] ..........(13.2)
Cable
Ig1: Leakage current on the electric channel from the leakage current breaker to the input terminals
of the servo amplifier (Found from Fig. 13.1.)
Ig2: Leakage current on the electric channel from the output terminals of the servo amplifier to the
servo motor (Found from Fig. 13.1.)
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 13.4.)
Igm: Leakage current of the servo motor (Found from Table 13.3.)
120
100
80
60
40
[mA]
20
0
Fig. 13.1 Leakage current example
(Ig1, Ig2) for CV cable run
in metal conduit
Noise
NV
filter
Servo
amplifier
Ig1 Ign Iga
Servo motor
output [kW]
2 3.5 8 1422 38 80 150
5.5 30 60 100
Cable size[mm 2 ]
Cable
SM
Ig2 Igm
Table 13.3 Servo motor's
leakage current
example (Igm)
Leakage
current [mA]
0.1 to 1.0 0.1
1.0 to 2.2 0.2
13 - 30
K: Constant considering the harmonic contents
Leakage current breaker
Mitsubishi
Type
products
NV-SP
Models provided with NV-SW
harmonic and surge NV-CP
reduction techniques NV-CW
NV-L
BV-C1
General models NFB
NV-L
Table 13.4 Servo amplifier's
leakage current
example (Iga)
Servo amplifier Leakage
capacity [kW] current [mA]
0.1 to 0.6 0.1
0.7 to 2.0 0.15
Table 13.5 Leakage circuit breaker selection example
Servo amplifier
MR-E-10A to MR-E-200A
K
1
3
Rated sensitivity
current of leakage
circuit breaker [mA]
15