1 Importance of Metal Connection Resistance Testing
In modern power systems and electronic engineering, metal connection quality directly determines the performance stability and safety reliability of electrical equipment. Although contact resistance between metal conductors may seem negligible, it is a critical parameter affecting overall electrical system efficiency. When contact resistance exceeds design limits, it causes severe operational issues:

• Abnormal Equipment Heating: Per Joule’s law (Q=I²Rt), energy converts to heat at resistive connection points. For example, in power systems, a mere 1mΩ increase in resistance under 100A current generates 10J of excess heat per second (equivalent to 10W continuous dissipation). This sustained heating accelerates insulation aging and reduces equipment lifespan.
• Signal Transmission Distortion: In precision electronics, abnormal contact resistance causes voltage drops and waveform distortion. In high-frequency signal transmission, impedance mismatch leads to signal reflection and attenuation, compromising data accuracy.
• Fire Hazards: Persistent heat may carbonize insulation, causing arc discharge or fires. Over 35% of electrical fires originate from poor connections.

Case Example: Frequent servo motor connector burnout in an automated production line was traced to 5.8mΩ contact resistance (exceeding ≤1mΩ design limits) due to micro-motion corrosion. Regular resistance testing could prevent such failures.

2 Testing Principles and Methods
2.1 Four-Wire (Kelvin) Method
This technique eliminates lead resistance errors by separating current injection (C1, C2) and voltage sensing (P1, P2) circuits. Resistance is calculated as R = ΔU / I. The FR3060 achieves precision down to 1μΩ.

2.2 Key Influencing Factors

• Test Current Selection: Optimize current for materials (FR3060’s ≥1A current suits large conductors; lower currents prevent heating in sensitive components).
• Thermal EMF Compensation: Current reversal cancels Seebeck-effect voltages at dissimilar metal junctions (e.g., Cu-Al).
• Contact Pressure Control: ≥5N stabilizes contact per GB/T34989-2017.

Table: Resistance Testing Methods Comparison

Method	Range	Accuracy	Application	Limitation
Two-Wire	1Ω-10MΩ	±(1%+5 digits)	General resistance	Lead resistance errors
Four-Wire (DC)	1μΩ-300kΩ	±(0.1%+2 digits)	Precision micro-resistance	Requires four terminals

3 FUZRR FR3060 Core Technologies
3.1 Four-Wire Architecture & Noise Immunity

• Precision current source (<0.05%/min drift)
• 24-bit Σ-Δ ADC with 0.1μV resolution
• Double-shielded cables meeting IEC61326-2-4 EMC standards

3.2 High-Current Testing & Safety

• ≥1A test current at ≤4.2V (SELV-compliant per IEC61010-1)
• Overload protection (220V/0.0001s) and reverse-connection alarms

3.3 Ergonomics & Data Management

• 480g lightweight design with 71×52mm LCD
• 500-group memory and microUSB data export

Table: FR3060 Key Specifications

Parameter	Specification	Standard
Range	0.001mΩ~300.0kΩ	JJG724-1991
Test Current	≥1A	DL/T967-2005
Accuracy	±(0.1%+2 digits)	JJG166-1993
Protection	CAT Ⅲ 600V	IEC61010-1

4 Application Scenarios
4.1 Power Connectors & Switchgear

• Live testing of GIS disconnectors at 750kV substations
• Identified 42μΩ abnormal resistance in C-phase contacts (vs. 28μΩ in A-phase)

4.2 Alloy Shunt Resistors

• Precision testing of Mn-Cu/Cu-Ni shunts (0.5mΩ range)
• TCR validation from -20℃~85℃ (±5ppm accuracy)

4.3 Grounding Systems

• Equipotential bonding verification per GB14050-2008 (≤0.05Ω)
• Diagnosed 0.85Ω faulty ammonia pipe grounding (corrected to 0.02Ω)

4.4 Extreme Environments

• Mining applications: Intrinsic safety design (≤4.2V/≤1A)
• Automotive: -185℃~350℃ resistance characterization

5 Operational Protocols
5.1 Pre-Test Preparation

• LOTO procedures and surface cleaning (120# abrasive for oxides)
• Temperature stabilization (1℃ ≈ 0.39% ΔR for copper)
• Instrument calibration with standard resistors

5.2 Critical Controls

• Test lead compensation (automatic zeroing)
• Torque-controlled contact pressure (5±0.5N)
• Multi-point measurements for large conductors

5.3 Environmental Compensation

• Temperature correction: R₂₀ = Rₜ / [1+α(t-20)] (Cu α=0.00393/℃)
• Thermal EMF cancellation via current reversal
• Humidity control (>75% RH requires drying)

6 Future Trends

• Micro-probes: MEMS Kelvin probes for 0.1mm BGA joints
• AI Diagnostics: ML-based degradation prediction
• Extreme Environments: 800℃ ceramic probes and nuclear radiation-hardened systems

7 Conclusion
The FR3060 DC low-resistance meter delivers critical precision for electrical reliability through its four-wire architecture, high-current capability, and rugged design. As Industry 4.0 advances, integration of temperature compensation, wireless connectivity, and predictive analytics will further solidify its role in safeguarding metal connections.