How does Power Cables With Metal Shield effectively reduce the impact of external electromagnetic interference on current transmission?
Publish Time: 2024-07-30
Power Cables With Metal Shield can effectively reduce the impact of external electromagnetic interference on current transmission through its special structure and material properties.1. Structure of Power Cables With Metal ShieldPower Cables With Metal Shield is mainly composed of internal conductor, insulation layer, metal shielding layer and outer sheath. Among them, the metal shielding layer is the key part. It is usually made of materials such as copper mesh, aluminum foil or tinned copper braided wire, tightly wrapped outside the insulation layer.2. Mechanism of reducing external electromagnetic interferenceReflection and shielding effect:The metal shielding layer can use the conductivity of metal materials to reflect external electromagnetic waves back, thereby reducing its direct interference to the internal conductor.At the same time, the metal shielding layer is also like a "shielding cover", isolating the internal conductor from the external electromagnetic environment to prevent the external electromagnetic field from interfering with the internal current.Grounding effect:The metal shielding layer usually needs to be grounded to guide the interference current that may enter the shielding layer into the earth, thereby eliminating its impact on the internal circuit.When grounding, the grounding point should be reliable and the grounding resistance should be low to ensure the smooth introduction of interference current.Skin effect:When high-frequency electromagnetic waves propagate in metal conductors, there will be a skin effect, that is, the electromagnetic waves are mainly concentrated on the surface of the conductor. The metal shielding layer uses this characteristic to limit the high-frequency interference electromagnetic waves to the surface of the shielding layer to prevent them from entering the internal conductor.Material selection:The conductivity and magnetic permeability of the metal shielding layer material have an important influence on the shielding effect. For example, copper has good conductivity and strong reflection and absorption capabilities for electromagnetic waves; although iron is not as conductive as copper, its magnetic permeability is higher and has a better shielding effect on low-frequency magnetic fields.3. Specific implementation methodSingle-ended grounding:For most cases, Power Cables With Metal Shield adopts single-ended grounding. This is because multi-point grounding may introduce ground loop currents, which will increase interference. Single-ended grounding can ensure that there is only one flow path for the current on the shielding layer, thereby avoiding the generation of ground loop currents.Reasonable wiring:When wiring, try to avoid parallel or close routing of Power Cables With Metal Shield with other lines that may generate electromagnetic interference (such as high-frequency signal lines, power lines, etc.). If it cannot be avoided, the spacing should be increased or shielding tubes and other measures should be used for isolation.Regular inspection and maintenance:Regularly check whether the shielding layer of Power Cables With Metal Shield is intact and the grounding is reliable. If damage or poor grounding is found, it should be repaired in time.Use multi-layer shielding structure:For occasions with higher requirements, a multi-layer shielding structure can be used to improve the shielding effect. For example, an insulating layer is first wrapped around the inner conductor, then a metal shielding layer is wrapped, and finally an outer sheath is added. This structure can more effectively isolate external electromagnetic interference.In summary, Power Cables With Metal Shield can effectively reduce the impact of external electromagnetic interference on current transmission through its special structure and material properties, as well as reasonable grounding and wiring methods.
