High Voltage DC Contactor

The KRIPAL UKD-H Series is a specialized switching device designed for controlling high-voltage direct current (HVDC) circuits. The key difference from an AC contactor lies in its advanced arc extinguishing capability. DC arcs are continuous and much harder to interrupt than AC arcs, which naturally extinguish at zero current.

The UKD-H Series is engineered to rapidly and safely extinguish these DC arcs, ensuring reliable circuit interruption. Using an AC contactor in a DC application is dangerous and can lead to contact welding, contactor destruction, and fire.

The UKD-H Series is versatile and critical in various high-voltage DC systems, including:

• Electric Buses & Vehicles: Manages the main power circuit, enabling safe connection and disconnection of the high-voltage battery.
• Charging Stations: Serves as a main power switch and control unit within DC fast chargers.
• Automotive Air Conditioning: Controls power to the high-voltage compressor in electric vehicles.

The energy-saving dual-coil design is a significant feature that enhances efficiency and reliability.

It operates in two stages:

• Pull-in Coil: A high-power coil is briefly energised to provide the initial force to quickly and reliably close the contactor's main contacts.
• Holding Coil: Once closed, a separate, low-power coil takes over to maintain the contactor in the closed position.

This design drastically reduces the overall power consumption and heat generation during continuous operation, improving longevity and system efficiency.

The IP67 rating is crucial for reliability in demanding environments. It certifies that the contactor is completely protected against dust ingress and can be immersed in water up to 1 meter for 30 minutes. This makes the KRIPAL UKD-H Series ideal for applications exposed to the elements, such as in electric vehicles, outdoor charging stations, or industrial settings where moisture, dust, or wash-downs are a concern.

Selecting the correct model involves matching its specifications to your system's requirements:

• Rated Current (50A-300A): Choose a model whose rated current exceeds your system's maximum continuous operating current. Include a safety margin for inrush currents.
• Coil Voltage (DC 9-36V): Ensure the coil voltage is compatible with your vehicle's or system's control voltage (e.g., 12V or 24V systems).
• Application Load: Consider the nature of the load (e.g., resistive, inductive, capacitive, like battery pre-charge) as it affects the switching stresses on the contactor.

Its reliability and stability, which are vital for overall system security and power quality, are derived from several key features:

• Robust Arc Extinction: Ensures clean and safe circuit interruption, protecting downstream components.
• Dual-Coil Energy-Saving Design: Reduces operating temperature and energy use, enhancing long-term stability.
• High Protection Rating (IP67): Guarantees performance in harsh, real-world conditions.
• Wide Current Range: Provides a precise solution for a broad spectrum of applications, from telecom to heavy-duty electric buses.