How to eliminate ground loop interference in frequency converters

To eliminate ground loop interference in frequency converters, it is necessary to cut off or block the noise current path formed by ground potential difference. Ground loops are common in frequency converter systems when the shielding layers of sensors are grounded at both ends, the shielding layers of motor cables are grounded at both ends, or when interconnected with devices such as PLCs. Elimination methods include: for analog signal sensors, using signal isolators or isolated transmitters to disconnect the direct ground connection. For communication interfaces, such as RS485, using isolated transceiver chips. For motor cables, their shielding layers are usually grounded at a single point at the frequency converter output, while floating at the motor end; however, safety regulations must be considered, and sometimes the motor end is grounded through a high-frequency capacitor. Connecting a common-mode choke in series on the signal line, such as the CMZ3225A-510T, can increase the ground loop impedance and suppress common-mode current. Optimize system grounding, ensuring that the frequency converter cabinet, motor housing, PLC cabinet, etc., are connected to the same grounding busbar through low-impedance conductors to reduce ground potential difference. Use balanced differential signal transmission. In cases where loops cannot be avoided, isolation transformers or optocouplers can be inserted into the loop. By analyzing the interference spectrum and loop impedance, the most suitable solution can be selected. The isolated communication modules and common-mode chokes provided by Audiotech are effective tools for eliminating ground loop interference.