High Voltage DC Contactor & DC Relay
BSB specializes in DC contactors (also referred to as DC relays) designed for reliable switching in electric vehicles, energy storage systems, and DC fast charging stations. Whether you’re looking for sealed performance or custom solutions, our product range covers it all.
Electric vehicles, charging equipment, energy storage systems, and industrial electronic control systems require robust power management solutions. BSB’s high-voltage DC contactors and relays are designed to meet these demands while also providing high-current circuit protection. Our contactors and relays support continuous current ratings of up to 800 A and maximum voltage ratings of up to 2.5 kV DC. The C7 series contactors utilize pulse-width modulation (PWM) technology to reduce the power required to keep contacts closed. Common applications include EV charging stations, uninterruptible power supplies (UPS), and DC motor controllers. Discover BSB’s DC contactor solutions today.
- High voltage and high current control
- Compact and lightweight design
- Arc-free space structure
- Safely sealed capsule structure
- High contact reliability
- Low noise
- Various models available
- Compliant with RoHS standards
- All series are certified by UL, CE, TÜV standards
What is a DC Contactor and DC Relay?
A DC contactor is a specialized electrical switch designed to control high-current direct current (DC) circuits. It operates through an electromagnetic mechanism that opens or closes the circuit by moving internal contacts. Compared to general-purpose relays, DC contactors are engineered for higher current loads, making them ideal for demanding applications such as electric vehicles (EVs), battery energy storage systems (BESS), and industrial power supplies.
While both DC contactors and DC relays share similar working principles, they serve different current ranges. DC relays are more suitable for lower current switching tasks, often found in control logic circuits and signal transmission. In contrast, high voltage DC contactors are built with robust arc-suppression systems and durable contact structures, allowing them to safely handle voltages up to 1500V and currents exceeding 500A. This makes them essential components in electric drivetrains and renewable energy systems where electrical interruption must be both fast and reliable.
Many high voltage DC Contactor relays used today integrate ceramic or epoxy-sealed designs to enhance insulation performance and withstand harsh operating conditions. Choosing between a contactor and a relay depends on the load type, voltage class, and whether auxiliary functions like feedback signals are required.
Terminology Note:
Although DC contactors and DC relays have technical distinctions, in real-world industry usage, the two terms are sometimes used interchangeably. Depending on regional habits or customer preferences, the same product may be referred to as a high voltage DC contactor or a high voltage DC relay. This is especially common in sectors like EV systems, ESS, and power conversion units, where both terms broadly imply an electromechanical DC switching component.
By understanding the distinctions between these components, engineers can ensure the safe and efficient operation of DC power systems—selecting the right DC contactor or DC relay according to system demands.
Choose the Right DC Contactor Relay for Your Project
We offer a variety of product series to suit different needs:
C7 Series: Epoxy sealed, general-purpose
C8 Series: Ceramic sealed, wide voltage range
C9 Series: Pre-charge relays
C10 Series: Extra-high current applications
BSBC7 Series
Voltage Rating Max: 1000VDC
Current Rating: 30ADC – 500ADC
Coil Voltage Rating: 12VDC, 24VDC, 12-24VDC, 9-36VDC, 48-72VDC
Sealing Method: Epoxy resin potting
BSBC8 Series
Voltage Rating Max: 1500VDC
Current Rating: 20ADC – 400ADC
Coil Voltage Rating: 12VDC, 24VDC
Sealing Method: Ceramic brazing
BSBC9 Series
Voltage Rating Max: 750VDC
Current Rating: 20ADC – 40ADC
Coil voltage Rating: 12VDC, 24VDC
Sealing Method: Air type
BSBC10 Series
Voltage Rating: 1500VDC, 2500VDC
Current Rating: 500ADC – 800ADC
Coil voltage Rating: 12VDC, 24VDC, 48VDC
Sealing Method: Ceramic brazing
BSB’s high voltage DC contactors are available in two distinct sealing technologies: epoxy resin encapsulation and ceramic brazed sealing, each paired with a specific arc-extinguishing gas to ensure performance and safety under demanding DC conditions.
Epoxy sealed contactors feature contact modules that are encapsulated with epoxy resin and filled with nitrogen. Nitrogen is chosen because it is chemically stable and compatible with epoxy. While hydrogen is the most effective arc-extinguishing gas, its low molecular weight makes it prone to leakage—epoxy cannot contain it securely. Nitrogen, though slightly less efficient, remains a safe and reliable alternative for arc suppression in epoxy-sealed modules.
Ceramic sealed contactors, on the other hand, utilize hydrogen gas enclosed within hermetically sealed ceramic housings through high-temperature brazing. Hydrogen is the most effective arc-extinguishing gas due to its high activity and low molecular weight, allowing it to rapidly absorb and remove heat from the arc. The ceramic structure ensures hydrogen remains sealed and stable over long-term operation, making it ideal for high-performance applications requiring superior arc suppression.
In short, epoxy + nitrogen offers cost-effective, compact sealing, while ceramic + hydrogen provides the highest arc-extinguishing efficiency for critical applications such as EVs, energy storage systems, and high-voltage DC switching.
Where Are DC Contactors and Relays Used?
BSB’s high voltage DC contactors relays have been on the market for over ten years, serving a wide range of high-demand applications. Our products are designed to meet the rigorous requirements of various sectors, ensuring high reliability and performance. The main application areas are:
- Passenger Vehicles: Providing reliable power control for electric cars.
- Buses: Ensuring safe and efficient operation of electric buses.
- Low-Speed Vehicles: Supporting power systems for low-speed electric vehicles.
- Logistics Vehicles: Enhancing the performance and reliability of electric logistics vehicles.
- Golf Carts: Ensuring consistent power supply for electric golf carts.
- Electric Forklifts: Providing robust power solutions for electric forklifts.
- Charging Stations and Chargers: Enhancing safety and reliability in EV charging infrastructure.
- Energy Storage Systems: Ensuring efficient operation and long-term reliability of battery storage systems.
- Photovoltaic Systems: Supporting stable operation in solar power applications.
- UPS (Uninterruptible Power Supply): Providing continuous power supply for critical systems.
- Industrial Automation Equipment: Enhancing performance and reliability in industrial automation systems.
EV Charging
Energy Storage
Photovoltaic
Electric Vehicle
Electric Construction Vehicle
High Speed Railway
How to select the appropriate DC contactors & relays?
Before selecting the appropriate BSB DC contactor, it is essential to understand the performance and operating conditions of the DC contactor. In some cases, testing under actual conditions may be required to ensure the most suitable contactor is chosen. We can quickly filter contactors based on the following conditions:
Main contact
The suitable product line can be quickly identified based on the current carrying capacity and voltage withstand ability of the main contacts. For example, if you are looking for a contactor for a 1500VDC circuit, you can easily narrow down to BSB’s product lines—C8 series and C10 series. The remaining parameters, such as polarity, the type of main contacts, and their form, can be considered to further select the appropriate product.
Coil
Typically, the information about the coil includes polarity, rated voltage, operating voltage, pick-up/release voltage, power consumption, and other relevant details.
Connection type
Common connection types include screw and PCB mounting methods.
Mechanical characteristics
They are mainly composed of core parameters such as mechanical life, electrical life, safety insulation, vibration resistance, and shock resistance.
Frequently Asked Questions (FAQs)
What is DC contactor & relay?
A DC contactor is a crucial electrical device used in DC (direct current) circuits to control the flow of electricity. It functions like a switch, opening and closing the circuit to allow or interrupt the current. Unlike AC contactors, which are designed for alternating current systems, DC contactors are specifically engineered to handle the unique characteristics of direct current power.A DC contactor is a crucial electrical device used in DC (direct current) circuits to control the flow of electricity. It functions like a switch, opening and closing the circuit to allow or interrupt the current. Unlike AC contactors, which are designed for alternating current systems, DC contactors are specifically engineered to handle the unique characteristics of direct current power.
How do DC contactors & relays work?
In a sealed DC contactor, when a control voltage is applied to the coil contacts, it generates a magnetic field that attracts the movable core to the fixed core. The movable contact attached to the movable core is pulled towards the fixed contact. When the contacts meet, the circuit is completed, allowing power to flow to the load. When the control voltage is interrupted, the magnetic field disappears, and the reset spring pushes the movable core back to its normal position, causing the contacts to separate and break the circuit.
What are the main advantages of DC contactors & relays?
- High current handling capability: DC contactors are designed to handle high current loads, making them suitable for industrial applications such as motor control, battery management systems, and renewable energy devices like solar panels.
- Durability and reliability: Due to their vacuum-sealed construction, DC contactors can switch DC power multiple times without wear or failure, providing long-lasting performance in critical systems.
- Safety: By isolating different parts of the system when necessary, DC contactors help prevent electrical overloads and short circuits, ensuring the safety of equipment and operators.
Why are DC contactors & relays important?
DC contactors play a critical role in many applications, including electric vehicles (EVs), DC charging equipment, solar power systems, and heavy machinery, by ensuring proper power control. They help prevent power surges, safeguard components, and efficiently manage large amounts of electrical energy. Whether managing small devices or large industrial systems, these components are essential for maintaining smooth and safe operation.