Bourns Introduces MSF Series Four-Terminal Shunt Power Resistors for Accurate High-Current Measurement

­Bourns today announced its Bourns® MSF Series Four-Terminal Shunt Power Resistors, including the MSF-2 and MSF-2L models, for accurate current measurement in high-current power systems. The series combines a four-terminal Kelvin measurement design with a 5 W power rating and resistance values from 0.5 mΩ to 5 mΩ. Maximum current is 100 A at 0.5 mΩ, with lower current at higher resistance values to stay within the 5 W rating.

Current measurement in battery management, power conversion, motor control, welding, and industrial power equipment can be affected by the resistance of leads, conductors, and electrical connections. The MSF Series separates the load-current path from the voltage-measurement path through its four-terminal Kelvin configuration, minimizing measurement errors caused by lead resistance. A Manganin® resistance element welded to oxygen-free high-conductivity copper terminals provides thermal stability, while a flame-resistant, high-temperature silicone coating protects the resistor. The series operates from -55 °C to +275 °C and provides a temperature coefficient of resistance (TCR) of ±100 ppm/°C from 0 °C to +85 °C.

“Accurate current measurement becomes more difficult as system current increases because resistance in the conductors and connections can influence the sensed voltage. The MSF Series uses a four-terminal Kelvin configuration to separate the measurement path from the load-current path, supporting current measurement up to 100 A with resistance values as low as 0.5 mΩ.”
— Walter Garcia, Product Line Manager, Resistors, Bourns

Design Features

• Radial, self-supporting construction — mounts directly on the PC board
• Four-terminal Kelvin design — minimizes errors caused by lead resistance
• 5 W power rating
• 100 A maximum current at 0.5 mΩ — higher resistance values carry less current to stay within the 5 W rating
• -55 °C to +275 °C operating range
• ±100 ppm/°C TCR — limits resistance variation from 0 °C to +85 °C; other TCR values are available by contacting Bourns
• Flame-resistant coating
• RoHS compliant*

Electrical Specifications

Target Applications

• Battery management systems (BMS)
• Power supplies and power conversion equipment
• Industrial motor controls
• Current monitoring circuits
• Welding equipment
• Energy storage systems
• Industrial automation and control systems

Availability
The MSF Series four-terminal shunt power resistors are available now through Bourns authorized distribution partners.