LT Series High Power Precision Shunt Resistors

What are the LT Series High Power Precision Shunt Resistors?

The LT is a high-power precision shunt resistor built on a metal clad substrate using four-terminal (Kelvin) construction. The four-terminal architecture physically isolates the current-carrying bus connections from the voltage-sense terminals, eliminating the contact and lead resistance errors that affect conventional two-terminal shunt measurements. This arrangement allows the LT to deliver accurate, low-noise voltage output signals at high continuous currents, making it suitable for systems where measurement integrity must be maintained throughout the full operating current and temperature range.

The series covers rated currents from 50A up to 500A, with resistance values ranging from 0.2mΩ to 2mΩ. Tolerance options of ±0.1%, ±0.5%, and ±1.0% are available, and the temperature coefficient of resistance (TCR) is a maximum of 30ppm/°C across the operating range. This combination of close initial tolerance and controlled TCR ensures that the resistance value and therefore the current measurement remains within the accuracy budget of precision monitoring and control systems across the full −25°C to +100°C temperature range.

The metal clad substrate provides structural rigidity and effective thermal management, enabling the LT to sustain rated continuous current under normal installation conditions. The heavy copper terminals are designed for direct connection to a current-carrying bus bar, while voltage sense connections are made through separate flexible wires attached to the dedicated sense terminals. This wiring arrangement decouples the sense circuit from the power path, ensuring that voltage drop measurements are taken at the resistive element itself rather than at the bus connection points, which would otherwise introduce variable offset errors.

The low-inductance construction of the LT ensures that the voltage output accurately tracks current waveforms without phase distortion or inductive overshoot, which is important in power conversion and energy storage applications where current slew rates can be high. Alongside the standard LT series, the closely related IRH-F series offers an extended current range beginning at 30A with resistance values up to 3.333mΩ, and UL-certified ULH variants are available for applications requiring third-party safety approval. Together these series form a comprehensive family of four-terminal metal clad shunts covering the full range of high-current measurement requirements from compact industrial drives through to large battery systems and renewable energy installations.

Model: LT
Resistor type: Current sensing
Description: High power precision
Rated Current: 50A~500A
Resistance (Ω): 0.2m~2m
Tolerance (%): ±0.1, ±0.5, ±1
TCR (ppm/C): 30

Model: PSS
Resistor type: Current sensing
Description: High power precision
Power Rating: 100W
Rated Current: 1400A max.
Resistance (Ω): 50u~1m
Tolerance (%): ±0.1, ±0.5, ±1
TCR (ppm/C): 3, 5, 10

Model: IRHF
Resistor type: Current sensing
Description: High power precision
Rated Current: 30A~500A
Resistance (Ω): 0.2m~3.333m
Tolerance (%): ±0.1, ±0.5, ±1
TCR (ppm/C): 15, 30

Model: HPS
Resistor type: Current sensing
Description: High power precision
Power Rating: 250W
Rated Current: 387A max.
Resistance (Ω): 1m~100m
Tolerance (%): ±0.05, ±0.1, ±0.5, ±1
TCR (ppm/C): 3, 5, 10

Model: UHPS
Resistor type: Current sensing
Description: Ultra high power precision
Power Rating: 100W
Rated Current: 707A max.
Resistance (Ω): 0.2m~1m
Tolerance (%): ±0.05, ±0.1, ±0.5, ±1
TCR (ppm/C): 3, 5, 10