Understanding Why Bimetallic Terminals In Dc Systems Can Withstand Dc Current For Extended Periods.

Low Contact Resistance and Thermodynamic Synergy

The design of the bi metallic cable lugs allows the copper and aluminum terminals to form a consistent current path when carrying DC current. The copper portion provides high conductivity close to that of pure copper conductors, reducing resistive losses in the system; the aluminum portion provides lightweight and good resistance to environmental corrosion. When DC current flows through the bimetal cable lug, the overall contact surface maintains low resistance characteristics, meaning reduced energy loss in the circuit and temperature rise of the terminal body and conductor contacts is kept within reasonable limits.

DC current does not have the frequency variation of AC current, therefore, no additional losses due to electromagnetic induction occur when current passes through the connection point. This is particularly important for the bimetal terminal lug, as steady-state DC conditions allow the bimetallic structure with its existing low-resistance contacts to continuously carry loads without significant additional thermal stress.

The following are the detailed factors related to long-term DC carrying capacity:

• Material Composition and Interface Bonding: Bimetallic terminals utilize friction welding or similar processes to form a strong bond between copper and aluminum, reducing the chance of microcracks forming at the interface.

• Thermal Expansion Matching: The difference in thermal expansion coefficients between copper and aluminum under temperature changes is reconciled through appropriate interface structure design, ensuring the contact interface maintains a stable geometry during thermal cycling and reducing the risk of mechanical fatigue.

• High Conductivity Path: The copper portion exhibits almost no significant AC resistance effect under DC conditions, resulting in extremely low overall resistance along the current path and reducing localized heating caused by current concentration.

Stability Performance During Operation and Maintenance:

In actual industrial and electrical installations, bimetallic terminals undergo rigorous testing under complex environments and long-term operating conditions. When operating in DC systems, a stable contact surface structure is crucial for extending the electrical life of the terminals. Due to specialized design and advanced manufacturing processes, these terminals demonstrate excellent connection stability and extremely low contact temperature rise under long-term DC loads, meeting the continuous operation requirements of DC power supply equipment and distribution networks.