What are the installation methods for shunt resistors?

As the core component of current sampling and measurement, the installation method of shunt resistor directly determines the measurement accuracy, heat dissipation performance, and system reliability. From laboratory precision measurement to industrial high current monitoring, the installation form of shunt has undergone an evolution from "universalization" to "scenarization". The following is a systematic review of the main installation methods for shunt resistors:
1、 Basic installation methods: slot type and non slot type
Slot Mount
Structural features: The splitter body is designed with a guide slot, which can be quickly plugged in and out in conjunction with a matching socket.
Application scenario: Suitable for scenarios with rated current ≤ 25A (such as laboratory power supplies, precision instruments), easy to replace and maintain frequently.
Advantages: Easy installation, stable contact resistance (usually<0.1m Ω), and support for hot plugging.
Limitations: The rated current is limited, and auxiliary heat dissipation is required in high current scenarios.
Non slot installation
Structural features: It is directly fixed on the circuit board through bolts or welding, and is divided into two types of packaging: vertical and horizontal.
Application scenario: Covering a wide current range of 30A to 15kA (such as electric vehicle charging stations, industrial welding machines), it needs to be used in conjunction with heat sinks.
Advantages: Strong current carrying capacity, short heat dissipation path, suitable for high-power scenarios.
Limitations: The installation process is complex and requires specialized tools.
2、 High precision scene specific installation method
Four terminal Kelvin connection
Structural features: The shunt body integrates four terminals, with two sets of terminals used for current path and voltage detection respectively.
Technical principle: By eliminating lead resistance errors through independent wiring, the measurement accuracy can reach 0.1% level.
Application scenarios: Battery tester, high-precision power supply (error<0.01%), required to be used in conjunction with low-noise operational amplifiers.
Implementation points: The detection line should be welded tightly to the resistor body to avoid thermal and electrical interference.
Flexible Circuit Board Installation (FPC)
Structural features: The splitter is directly printed on a flexible substrate and bonded to the tested conductor through conductive adhesive.
Application scenarios: Wearable devices, medical patch sensors, which need to adapt to curved installation.
Advantages: High space utilization and low parasitic inductance (<1nH).
Limitations: Low power density (usually<1W), requiring specialized packaging processes.
3、 Specialized installation method for industrial high current scenarios
Copper bar embedded installation
Structural features: The shunt resistor strip is directly embedded inside the copper bar, and low resistance connection is achieved through laser welding.
Application scenarios: Photovoltaic inverters, energy storage converters (with currents up to thousands of amperes), which need to withstand strong electromagnetic interference.
Advantages: Large heat dissipation area, low temperature rise (<5K), strong anti vibration ability.
Implementation points: X-ray inspection is required at the welding site to ensure no virtual welding.
Water cooled installation
Structural features: The splitter is integrated with the water-cooled plate and dissipates heat through the circulation of deionized water.
Application scenarios: Electric vehicle motor controllers, laser processing equipment (power>100kW).
Advantages: The current carrying capacity is increased by more than 3 times, and the temperature rise is controllable (<2K).
Limitations: High system complexity, requiring leak proof design.
4、 Special environmental adaptability installation method
Explosion proof installation
Structural features: The splitter is enclosed in an explosion-proof shell and filled with flame-retardant gel.
Application scenarios: Explosion proof areas such as coal mines and petrochemicals (Ex d IIC T6 level).
Implementation points: The shell needs to pass a 10 bar pressure test, and the leads should use armored cables.
Vacuum packaging installation
Structural features: The splitter is welded inside the vacuum chamber to eliminate oxidation effects.
Application scenarios: Satellite power systems, high-energy physics experiments (with a lifespan requirement of>20 years).
Advantages: High resistance stability (<10ppm/year), strong radiation resistance.
5、 General Installation Specifications and Precautions
Contact resistance control
The contact resistance at the primary circuit connection should be less than 0.5m Ω. It is recommended to use silver plated bolts or ultrasonic welding.
The secondary sampling point must be directly welded to the end face of the resistor, and sampling from the connecting piece is prohibited.
polarity management
The current inflow terminal (positive pole) is connected to the positive input terminal of the instrument signal, and the outflow terminal (negative pole) is connected to the negative input terminal.
Incorrect polarity will cause measurement values to reverse, which may damage sensitive components.
Current overload limit
It is recommended that the actual current used should not exceed 80% of the rated value, for example, the long-term operating current of a 75mV/200A shunt should be less than 160A.
emc
In high current scenarios, magnetic rings or metal shielding covers need to be installed around the shunt to suppress electromagnetic interference.
The signal line adopts twisted pair shielded cable, and the shielding layer is grounded at a single point.
6、 Emerging installation technology trends
3D Stacking Installation
By using TSV (Through Silicon Via) technology to achieve vertical interconnection between the shunt and the chip, the volume is reduced to the 0402 level.
Applied to current detection modules in advanced packaging such as SiP and 2.5D/3D ICs.
Self healing installation
The shunt is integrated with a fuse, which melts and triggers an alarm signal when overcurrent occurs.
Suitable for unmanned scenarios such as data center power supply and communication base stations.
The installation method of shunt resistors is a deep integration of material characteristics, circuit topology, and application scenarios. The evolution of installation forms from slot type to four terminal Kelvin connection, from copper bar embedded to water-cooled installation, not only reflects the improvement of measurement accuracy, but also reflects the eternal pursuit of reliability, miniaturization, and intelligence in industrial systems. With breakthroughs in fields such as new energy and aerospace, splitter installation technology will continue to evolve towards "integration, adaptability, and maintenance free" direction.