Earth-Leakage Current Breaker; Selection Method - Mitsubishi Electric MELSERVO MR-J5 Series User Manual

6.16

Earth-leakage current breaker

Selection method

High-frequency chopper currents controlled by pulse width modulation flow in the AC servo circuits. Leakage currents
containing harmonics 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 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.
• MR-J5-_G_, MR-J5-_B_ or MR-J5-_A_
Rated sensitivity current ≥ 10 • {Ig1 + Ign + Iga + K • (Ig2 + Igm)} [mA] . . . (6.1)
Cable
NV Noise filter
amplifier
Ig1 Ign
• MR-J5W_-_
Rated sensitivity current ≥ 10 • {Ig1 + Ign + Iga + K • (Ig2 (A-axis) + Igm (A-axis) + Ig2 (B-axis) + Igm (B-axis) + Ig2 (C-axis) +
Igm (C-axis))} [mA] . . . (6.2)
Cable
NV Noise filter
amplifier
Ig1 Ign
Earth-leakage current breaker
Type
Models provided with harmonics 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 servo
amplifier
Page 363 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 servo amplifier to the servo motor
Page 363 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: Servo amplifier leakage current
Page 364 Servo amplifier leakage current example (Iga)
Igm: Servo motor leakage current
Page 363 Servo motor leakage current example (Igm)
6 OPTIONS AND PERIPHERAL EQUIPMENT
362
6.16 Earth-leakage current breaker
Cable
Servo
M
Iga Ig2 Igm
Cable
M A-axis
Ig2 Igm
Cable
Servo
M
B-axis
Igm
Ig2
Iga
Cable
M
C-axis
Ig2 Igm
Mitsubishi Electric products
NV-SP
NV-SW
NV-CP
NV-CW
NV-HW
BV-C1
NFB
NV-L
K
1
3