Earth-Leakage Current Breaker; Selection Method - Mitsubishi Electric -MR-CV User Manual

10.6

Earth-leakage current breaker

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 runs on AC power.
Select an earth-leakage current breaker according to the following formula, and ground the converter unit, drive unit, servo
amplifier, servo motor, etc. securely.
To minimize leakage currents, make the input and output wires as short as possible, and keep a distance of 30 cm or longer
between the wires and ground.
Rated sensitivity current ≥ 10 • {Ig1 + Ign + Iga + K • (Ig2 + Igm)} [mA] . . . (10.1)
Wire
Noise filter
NV
Ig1 Ign
Earth-leakage current breaker
Type
Models provided with harmonic and surge
reduction techniques
General models
Ig1: Leakage current on the electric channel from the earth-leakage current breaker to the input terminals of the converter unit
Page 101 Example of leakage current (Ig1, Ig2) per km of CV cable run in metal conduit
Ig2: Leakage current on the electric channel from the output terminals of the drive unit to the servo motor
Page 101 Example of leakage current (Ig1, Ig2) per km of CV cable run in metal conduit
Ign: Leakage current when a filter is connected to the input side (4.4 mA per one FR-BIF(-H))
Iga: Leakage current of the converter unit and drive unit
The leakage current of the MR-CV_ power regeneration converter unit is 5 mA for all series. For the leakage current of the
drive units, refer to the manual and instruction manual of each drive unit.
Igm: Servo motor leakage current
Refer to the manual and instruction manual for each drive unit.
10 OPTIONS AND PERIPHERAL EQUIPMENT
100
10.6 Earth-leakage current breaker
Wire
Converter
Drive unit
unit
Ig2
Iga
Mitsubishi Electric products
NV-SV
NV-SVF
NV-SW
NV-CV
NV-CVF
NV-CW
NV-HV
BV-C1
M
Igm
K
1
3