Shielded cables can allow external electromagnetic radiation and magnetic field radiation to directly enter the ground without interfering with the inner wires. In general, shielded cables have two layers of shielding. Mesh braided wire is used to prevent magnetic field radiation, and aluminum foil layer is used to prevent electromagnetic radiation. The shielding layer must be grounded in order to have a good shielding effect. When high-frequency electromagnetic fields from the outside pass through the shielding layer, eddy currents are generated and consumed.
Shielded cable is a special type of cable with a mesh braided wire on the outer layer. Cable shielding refers to the outer layer of the mesh braided wire being grounded at one end, which allows external electromagnetic radiation and magnetic field radiation to directly enter the ground without interfering with the inner wires.
Generally, coaxial cables are used for cable TV, and leads from the frequency converter to the motor are used. In areas with interference, the power supply should also be shielded, and analog leads should also be used.
Shielded cables require anti-interference to prevent external electromagnetic fields from entering the circuit. Generally, shielded cables are used for circuits with high frequencies and low signal levels. The most common type is coaxial cable for cable TV, which has a metal mesh outside the inner conductor for shielding and is also one of the signal circuits. The core wire of communication cables, except for copper conductors, is wrapped with a layer of aluminum foil and grounded to provide shielding.