BR/BRT BR/BRT Wirewound Resistors

BR/BRT is a series of high-power wirewound resistors manufactured by Bourns, a global leader in sensing, protection, and control solutions. These robust passive components are specifically designed for applications requiring significant power dissipation, offering reliable performance in demanding environments. As wirewound resistors, they utilize a resistive wire wound around a non-conductive core, providing excellent stability and precision for critical circuit functions.

Key Specifications

The Tolerances of 1%, 5%, and 10% indicate the permissible deviation from the nominal resistance value. A 1% tolerance signifies a high-precision component suitable for applications where exact resistance is critical, while 5% and 10% tolerances are common for general-purpose power applications where some deviation is acceptable. The choice of tolerance impacts the overall accuracy and cost-effectiveness of the circuit.

With a remarkable Power (Watts) range of 60 to 500 W, the BR/BRT series is engineered for extreme power handling. This wide range allows designers to select the appropriate resistor for applications involving substantial current flow and heat generation, such as motor control, power supplies, and industrial machinery. The ability to dissipate such high power levels is a hallmark of their robust construction.

The Component Type is explicitly Wirewound Resistors. This classification highlights their construction method, which involves winding a resistive wire around a ceramic or fiberglass core. This design is inherently stable and capable of handling higher power levels and temperatures compared to other resistor types like carbon film or metal film, making them ideal for heavy-duty applications.

The Resistance Range of 0.1-1K Ω (Ohms) provides versatility for various circuit designs. From very low resistance values, often used for current sensing or discharge applications, to higher values suitable for voltage division or load applications, this range covers a broad spectrum of industrial and power electronics needs. This flexibility ensures that the BR/BRT series can be integrated into diverse systems.

The Profile/Package Style is described as a High Power Metal Clad Braking Resistor. This indicates a specialized design where the resistive element is encased in a metal housing, often aluminum, which acts as a heatsink. This metal cladding facilitates efficient heat dissipation, allowing the resistor to operate at its high power ratings without overheating. The term “Braking Resistor” specifically points to their common use in dynamic braking systems for motors, where they dissipate regenerative energy.

A Temperature Coefficient of < 260 PPM/°C (Parts Per Million per Degree Celsius) signifies the change in resistance per degree Celsius change in temperature. A low temperature coefficient is crucial for applications requiring stable resistance over varying operating temperatures. This value indicates that the BR/BRT resistors maintain their specified resistance with minimal drift, ensuring consistent circuit performance even under fluctuating thermal conditions.

Features and Benefits

• Exceptional Power Handling: Designed to dissipate significant power from 60W to 500W, making them ideal for heavy-duty industrial and power electronics applications.
• Robust Metal Clad Construction: The high-power metal clad package ensures superior heat dissipation and mechanical protection, contributing to a longer operational lifespan and enhanced reliability in harsh environments.
• Wide Resistance Range: Offering a broad resistance range from 0.1Ω to 1KΩ, these resistors provide flexibility for diverse circuit designs, from current limiting to load balancing.
• Stable Performance Across Temperatures: With a low temperature coefficient of less than 260 PPM/°C, the BR/BRT series maintains stable resistance values over a wide operating temperature range, ensuring consistent circuit performance.
• Precision and Reliability: Available in tolerances down to 1%, these wirewound resistors offer high precision and dependable operation, critical for sensitive control and measurement systems.

Typical Applications

The BR/BRT series of Bourns wirewound resistors finds extensive use in various demanding applications due to their high power handling and robust construction. One primary application is in Dynamic Braking Systems for Motors. In these systems, when an electric motor decelerates, it acts as a generator, feeding energy back into the power supply. Braking resistors like the BR/BRT dissipate this regenerative energy as heat, preventing overvoltage conditions and allowing for controlled and rapid motor stopping. This is crucial in industrial machinery, elevators, and electric vehicles.

Another significant application is in Power Supplies and Inverters. High-power resistors are essential for current limiting, voltage division, and discharge functions within large-scale power conversion circuits. They help stabilize output voltages, protect components from surge currents, and ensure safe discharge of capacitors, particularly in high-voltage DC-DC converters and grid-tied inverters.

They are also widely used in Industrial Control Systems. This includes applications such as load banks for testing power sources, heating elements in industrial processes, and current sensing in heavy machinery. The ability of the BR/BRT resistors to handle high power and maintain stability under varying conditions makes them indispensable for reliable operation in factory automation and process control.

Furthermore, these resistors are critical in Renewable Energy Systems, particularly in wind turbines and solar inverters. They are employed in crowbar circuits for overvoltage protection, in charge/discharge control for battery energy storage systems, and as dump loads to manage excess power generated by renewable sources, ensuring system stability and longevity.

Finally, the BR/BRT series is suitable for Test and Measurement Equipment where high power dissipation and precision are required. This includes specialized laboratory equipment, power test benches, and burn-in systems for electronic components, where accurate and stable resistive loads are necessary for reliable testing and characterization.

The Bourns BR/BRT series offers a reliable and high-performance solution for demanding power dissipation requirements across numerous industrial and power electronics applications. These robust wirewound resistors are stocked and shipped across India by Cirkit Electro Components, Mumbai, ensuring prompt availability for your critical projects.

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