Working Principle Of Terminal Block: In-depth Analysis Of Electrical Connection Mechanism
Terminal blocks are the core components in electrical systems that enable reliable connection of wires. Their working principle is based on a dual mechanism of mechanical fixation and conductive contact, ensuring the stability and safety of current transmission through the combination of physical structure and material science.
From the perspective of mechanical structure, terminal blocks are usually composed of three parts: insulated housing, conductive metal parts, and fastening devices. Taking the common screw type terminal block as an example, its conductive metal part is a metal sheet, with wire insertion holes at both ends. By rotating the screw to push the clamping block downwards, the wire metal conductor is tightly attached to the metal sheet. This "lifting cylinder structure" utilizes the "Reakdyn principle" to prevent loosening through a screw self-locking mechanism, ensuring constant contact pressure. Even if the wire undergoes slight deformation due to thermal expansion and contraction, it can maintain a stable electrical connection.
At the level of conductive contact, the design of terminal blocks must meet the requirements of low resistance and high current carrying capacity. Conductive metal parts are often made of copper alloys or tin plated copper, and surface treatment can reduce contact resistance and heat generation. For example, the UT series terminals of Phoenix Contact use stress corrosion resistant alloy copper for their wire frame, which can carry current. At the same time, through a double-layer structure design, the upper and lower layers are misaligned to avoid operational interference. For high current scenarios such as power transformer connections, the TB series high current terminals ensure system safety by increasing the contact area and reducing local temperature rise.
In addition, the wiring terminals also enhance flexibility through modular design. Plug in terminals utilize wire frame technology, supporting large wire diameter access without the need for tool disassembly; Spring type terminals use a pullback spring structure to achieve one handed quick wiring, suitable for dense wiring scenarios. In terms of safety protection, some terminals are integrated with optoelectronic coupling modules to isolate on-site signals from control devices, avoid electromagnetic interference, and meet the matching requirements of high voltage and low power.
