PMS Series Power Metering Shunt Resistors

What are the PMS Series Power Metering Shunt Resistors?

The PMS is a power metering shunt resistor rated at 3W and designed for precision inline current measurement across a rated current range of 15A to 100A. As a series-inserted shunt, it generates a small millivolt-level voltage drop proportional to the load current, allowing the current to be accurately calculated from the measured voltage according to Ohm's Law without interrupting the load path. The resistance range spans 0.1mΩ to 1.2mΩ, placing the PMS firmly in the milliohm domain characteristic of high-current power metering applications where minimising resistive power loss while maintaining a measurable sense voltage are equally critical design constraints.

Tolerance options of ±1%, ±5%, and ±10% are offered across the range, giving designers the flexibility to balance cost against measurement accuracy for the specific metering application. The temperature coefficient of resistance (TCR) is 50 ppm/°C, a value appropriate for billing-grade industrial energy metering where resistance stability over the operating temperature range is essential to sustained measurement accuracy. At 50 ppm/°C, the PMS falls within the performance band associated with manganin and similar low-TCR resistance alloys widely used in revenue-grade metering components.

The PMS is engineered for PCB-mount installation, integrating directly into the metering board alongside the analogue front-end and metrology IC without the additional hardware or wiring overhead associated with panel-mount shunt designs. Its compact form factor and defined terminal geometry suit the five-terminal configurations commonly used in energy metering shunt designs, where the current-carrying terminals and the sense terminals are separated to eliminate lead resistance errors from the voltage measurement path — a technique known as Kelvin or four-wire connection. This construction ensures that the resistance seen by the metering circuit corresponds precisely to the calibrated element resistance rather than being inflated by connector or trace resistance in the current path.

The PMS is positioned within a broader current sensing range from RARA that extends from AEC-Q200 automotive chip shunts at the low-current end to high-amperage panel shunts rated up to 12,000A at the high end. Within this portfolio, the PMS addresses the metering-grade segment where current levels are modest but accuracy requirements are stringent — energy meters, substation metering panels, and industrial revenue meters that demand long-term resistance stability and a low, consistent TCR for billing-grade performance.

Model: PMS
Resistor type: Current Sensing
Description: Power metering shunt
Power Rating: 3W
Rated Current: 15A~100A
Resistance (Ω): 0.1m~1.2m
Tolerance (%): ±1, ±5, ±10
TCR (ppm/C): 50

Model: BWH
Resistor type: Current Sensing
Description: Through Hole
Power Rating: 3W~5W
Resistance (Ω): 0.3m~3m
Tolerance (%): ±1, ±2, ±5
TCR (ppm/C): 100, 300

Model: BWT
Resistor type: Current Sensing
Description: Through Hole
Power Rating: 2W, 5W
Resistance (Ω): 0.5m~10m
Tolerance (%): ±1, ±5
TCR (ppm/C): 50

Model: CSR
Resistor type: Through hole shunt
Description: Through hole 2 terminal
Rated Current: 2A-12A
Resistance (Ω): 20m~200m
Tolerance (%): ±5, ±10
TCR (ppm/C): 260

More Information

Model: BWR05
Resistor type: Current sensing
Description: AEC-Q200 Chip Shunt
Power Rating: 3W~7W
Resistance (Ω): 1m~5m
Tolerance (%): ±0.5, ±1, ±5
TCR (ppm/C): 50, 75