Safety tester UHV-5A

resistancelow-resistancefor electrical equipment

Overview
This portable instrument measures DC winding resistance of transformers and inductive loads using current-source compensation and four-wire (Kelvin) measurement to eliminate lead/contact resistance errors. It integrates overvoltage protection, a rechargeable lithium-ion battery for field use and a high output current capability for precise, repeatable measurements.

Product parameters

Type integrated portable
Dimensions: 260 mm × 160 mm × 80 mm
Weight: 3 kg
Battery: built-in rechargeable DC lithium-ion
Charger: input AC 220 V (50±1) Hz — output DC 29.4 V
Operating temperature: -10 °C to 45 °C
Relative humidity: ≤85% RH (no condensation)
Maximum altitude: ≤2000 m
Maximum output power: 100 W (5 A current level; open-circuit voltage ≈20 V)

Range and accuracy
Item Detail Parameter
Current 5A Automatic、5A、1A、100mA、1mA
Display Four and a half
Test range 5A 1μΩ~4Ω
1A 20mΩ~20Ω
100mA 200mΩ~200Ω
≤1mA 20Ω~100kΩ
Accuracy 0.2% ±2 digits

Features

• Display: 5.0-inch true-color touch LCD (Chinese interface; English available on request)
• Storage: stores up to 1,000 test records
• Test mode: built-in high-capacity lithium battery for DC power — suitable for outdoor inspections
• Current options: five automatic current settings (including 5 A)
• High precision: accuracy 0.2% ± 2 digits
• Measurement range: 1 μΩ to 100 kΩ; resolution 0.1 μΩ
• Printing: integrated high-speed micro thermal printer for real-time printout
• File management: USB mass-storage mode for direct copying of test records
• Parameter settings: configurable fields — serial number, material, test winding phase, winding temperature and converted temperature
• Automatic shutdown: powers off after 3 minutes of inactivity
• Power display: battery level shown at startup
• Low-battery protection: low-battery warning and controlled shutdown to protect the battery

Additional notes
Measurement method: four-wire (Kelvin) measurement to remove lead/contact resistance influence. Protection: integrated overvoltage and comprehensive protection functions to ensure instrument safety and repeatability in field and laboratory environments.

Technical specifications

• Model: UHV-5A
• Type: integrated portable
• Dimensions: 260 mm × 160 mm × 80 mm
• Weight: 3 kg
• Power supply: built-in rechargeable DC lithium-ion battery; charger input AC 220 V (50±1) Hz, output DC 29.4 V
• Operating temperature: -10 °C to 45 °C
• Relative humidity: ≤85% RH (no condensation)
• Maximum altitude: ≤2000 m
• Maximum output power: 100 W (5 A; open-circuit voltage ≈20 V)
• Measurement range: 1 μΩ to 100 kΩ; resolution 0.1 μΩ
• Accuracy: 0.2% ± 2 digits
• Display: 5.0-inch true-color touch LCD
• Storage: up to 1,000 records
• Current settings: five automatic levels
• Printer: built-in high-speed micro thermal printer
• Data transfer: USB mass-storage mode for direct file copy
• Protection features: overvoltage protection and comprehensive safety functions

Principle of action

• A DC resistance tester is an instrument that measures the current in a circuit by applying a certain DC voltage, and calculates the resistance value of the circuit. It is based on Ohm's law and quickly and accurately obtains the resistance value of a circuit by measuring the current value and the applied voltage value. In practical applications, attention should be paid to factors such as contact resistance and temperature drift to ensure the accuracy of measurement results. DC resistance tester has a wide range of applications in electronics, power, communication and other fields, playing an important role in troubleshooting circuit faults and quality inspection of electrical components.