Shielding technology
Using shielded cables is one of the effective ways to reduce electromagnetic interference. Shielded cables can effectively suppress the radiation and conduction of electromagnetic waves, as well as the noise current caused by high-order harmonics. For example, when using elevator motor cables driven by frequency converters, shielded cables must be used. The conductivity of the shielding layer is at least 1/10 of the electrical conductor of each phase conductor core, and the shielding layer should be reliably grounded. In addition, the control cable and the transmission line of the analog signal should use double-shielded twisted pair cables, and different analog signal lines should be routed independently with their own shielding layers.
Grounding technology
Good grounding can eliminate electromagnetic interference. Make sure that the equipment in the elevator control cabinet is well grounded, and the thick grounding wire is connected to the power supply line grounding point (PE) or the grounding busbar. It is particularly important that any electronic control equipment connected to the frequency converter must be grounded with it, and short and thick wires should be used when sharing the ground.
Wiring technology
Reasonable wiring technology can improve electromagnetic interference. For example, the motor cable should be routed independently of other cables, and the motor cable should not be routed parallel to other cables for a long distance to reduce the electromagnetic interference caused by the rapid change of the inverter output voltage; when the control cable and the power cable cross, they should be crossed at a 90° angle as much as possible, and the shielding layer of the motor cable and the control cable must be fixed to the mounting plate with a suitable wire clamp.
Filtering technology
Filtering technology can reduce electromagnetic interference. Among the problems that often occur in electromagnetic compatibility testing, differential mode interference and common mode interference are two common interference currents. Differential mode interference current and common mode interference current can be directly conducted into the circuit module or other devices of electronic equipment through cables, and can also generate electromagnetic fields in space to form radiation interference. In order to reduce these interference currents, filtering methods can be used to prevent interference currents from entering other devices or circuits to cause interference.
Conclusion
In summary, reducing electromagnetic interference of LAN cables can be achieved through a variety of methods, including using shielded cables, ensuring good grounding, adopting reasonable wiring techniques, and using filtering techniques. These methods can be used alone or in combination according to specific circumstances to achieve the best anti-interference effect.