Portable 120A Loop Resistance Tester

Portable 120A Loop Resistance Tester

MOEORW-W5010P is a compact handheld micro-ohm measuring instrument engineered for on-site resistance verification of high-voltage switch contact loops and low-resistance conductive components. Adopting DC voltage drop measurement specified in GB763 and complying with DL/T 845.4-2004 industry specification, the unit outputs adjustable high DC current up to 120A to eliminate lead resistance interference and realize precision micro-ohm detection. Built-in large-capacity rechargeable lithium battery supports field testing without external AC power supply; compact dimension and lightweight structure enable flexible handheld operation for substation maintenance, switchgear factory incoming inspection and field commissioning scenarios. All measurement logics follow four-wire Kelvin testing principle to separate current excitation and voltage sampling terminals, drastically improving testing accuracy for ultra-low resistance specimens.

3.1 Hardware & Structural Design

1. Integrated high-density lithium battery pack inside the enclosure, eliminating external mains connection restriction for outdoor field inspection; full-color LCD screen with adjustable backlight and volume control for diversified on-site ambient viewing and voice reading after measurement completion.2. Independent dual-terminal wiring layout: C1/C2 for high-current output, P1/P2 for low-signal voltage sampling, strictly separating excitation and sampling circuits to comply with four-wire measurement standard; dedicated matched test leads with color-coded thick/thin split wiring to standardize field connection.3. Multi-layer built-in protection circuit: open-circuit detection, overtemperature automatic shutdown protection, abnormal connection intelligent interlock, avoiding equipment damage from miswiring or overheating.

3.2 Measurement Performance Advantages

1. Multi-grade current selection from 30A up to 120A matches segmented resistance testing range, realizing full coverage from micro-ohm to 20mΩ resistance measurement; customized testing duration from 1s to 60s optimizes thermal accumulation during long-time high-current output and reduces equipment heating loss.2. Ultra-high 0.1μΩ resolution plus ±(0.5%RD+2μΩ) precision ensures reliable identification of minor contact degradation on high-voltage breaker contacts and switch junctions.

3.3 Post-test Data Management Value

1. Local storage of maximum 200 test datasets with auto date-based file naming and editable custom serial number for batch asset management of tested equipment.2. Four diversified data export approaches: U-disk one-click export (saved as TestData.txt), Bluetooth wireless printing, QR code generation (max.50 records per QR for mobile scanning), and on-device historical data browsing with page-up/down flip, meeting lab filing, field spot archiving and remote data synchronization requirements.

The tester executes DC voltage drop (four-wire Kelvin) measurement: constant DC high current is injected into the tested specimen via C1/C2 current terminals, while P1/P2 voltage terminals pick up the tiny voltage drop generated across the measured resistance; built-in MCU calculates resistance value following Ohm's Law (R=U/I). Separated current & voltage terminals eliminate the inherent resistance error of test leads and clamping fixtures, which is the core guarantee of μΩ-level measurement precision.

• Power grid industry: On-site maintenance & routine inspection of high-voltage AC/DC circuit breakers, disconnecting switches, GIS cabinet conductive loops in substations.· HV equipment manufacturing: Factory incoming inspection and finished-product test for high-voltage switchgear, busbar lap joints, contact assemblies.· Rail transit & new energy: Resistance testing of high-current switch contacts inside wind power converters, locomotive high-voltage cabinet components.· Third-party testing institutions: Routine verification of low-resistance conductive components for power equipment acceptance inspection.

1. National Standard GB763 (DC voltage drop testing specification for loop resistance measurement)2. China Electric Power Industry Standard DL/T 845.4-2004 (General technical requirements for resistance measuring instruments, Part4: Loop Resistance Tester)3. JJG1052-2009 (National Metrology Verification Regulation for Loop Resistance Tester)

1. Dedicated color-coded split-type test lead set (red/black, thick current wire + thin sampling wire, factory calibrated <10mΩ resistance)2. Exclusive 12.6V/3A lithium battery AC charger (100~240VAC input)3. Original English & Chinese operation manual V4.30 version4. Standard storage packing case

1. Storage requirement for long-term idle: Keep battery residual capacity above 60%; monthly regular power inspection, supplementary charging when power is insufficient to avoid lithium battery over-damage.

2. Charging regulation: Only adopt original dedicated charger; red indicator during charging, green indicator for fully charged state, prohibit mismatched third-party power adapter.

3. Storage environment: Keep away from high-temperature surroundings, long-time direct sunlight, physical extrusion and violent falling; internal disassembly by end-user is prohibited to void after-sales warranty.

4. After each field test: Clean dirt on test clip and wiring terminals to guarantee stable clamping contact and reduce extra lead resistance.

5. Live-site test precondition: Ensure one end of the tested specimen is reliably grounded prior to wiring connection for operational safety.