How to suppress common-mode current in industrial servo equipotential bonding?

Establishing equipotential bonding among all components within the servo system is the fundamental method for suppressing common-mode current flow. Eintech's implementation plan:

First, ensure all metal components within the cabinet (backplate, mounting beams, doors) are connected to the main grounding copper busbar via low impedance, with the impedance between any two points at 10MHz <10mΩ.

Second, establish equipotential bonding lines for components that may generate potential differences (such as the motor housing and driver housing), using multi-strand copper wire with a cross-sectional area >4mm², as short as possible, and wrapping PBZ ferrite beads along the lines to suppress high-frequency current.

At the PCB level, provide independent grounding islands for different functional blocks (such as drive, control, and communication), and connect them at a single point at the power input via zero-ohm resistors or ferrite beads. After equipotential design, using a common-mode current probe, the common-mode current on the motor cable should be reduced by more than 60%, corresponding to a 6-10dB margin improvement in the 150kHz-30MHz frequency band during conducted interference testing, meeting the EN 55032 standard.