How to connect the shielding ground and power ground of an industrial servo motor?

The connection method between the servo shielding ground (cable shielding layer, chassis) and the power ground (internal high-current ground) directly affects the shielding effect and ground loops. Etymotic recommends the following connection principles: the shielding ground should be connected to the power ground at a single point, and this point should be chosen near the grounding reference point of the noise source (such as the IGBT), typically the negative terminal of the DC bus capacitor or the cabinet grounding bus. The connection should use a low-impedance path, such as a metal spring or grounding clamp, rather than through thin wires. For multi-core cables, the shielding layer should be connected to the shielding ground at a single point on the driver side, and at the motor side, it should be coupled to the motor housing at high frequency through a Y capacitor (such as 2.2nF/Y1) to achieve high-frequency noise discharge and avoid low-frequency ground loops. On the PCB, the shielding connector housing should be directly connected to the chassis ground plane through multiple vias, not the signal ground. Correct connections can improve shielding effectiveness by more than 15dB and prevent the shielding layer from becoming a radiating antenna due to potential differences.