I. Introduction

This manual applies to the HZ-5200 loop resistance tester.
This instrument is designed for the accurate measurement of contact resistance at circuit breaker contacts, busbar joints, contact elements in busbars, cable joints, and other high-current connections.

When contact resistance increases abnormally due to oxidation, loose threads, insufficient clamping force, or long-term aging, abnormal heat will be generated at the contact point when current flows. This heat will further accelerate oxidation and mechanical relaxation, leading to a decrease in conductivity and forming a vicious cycle of "heating → increased resistance → more severe heat generation," which may ultimately cause equipment failure or even burnout.

The HZ-5200 loop resistance tester employs a high-current constant current source and Kelvin four-wire measurement method to quickly and accurately measure contact resistance at the micro-ohm level, helping users detect potential problems before they escalate to an uncontrollable stage. Regularly using this instrument to check contact resistance can effectively assess the health of electrical connections, providing a reliable basis for preventative equipment maintenance.

Performance Characteristics

1. The instrument can be controlled entirely via a mobile phone using dedicated software. Test data is stored on the phone in a fixed format for easy data retrieval at any time.

2. Multiple protection functions are included during testing, such as protection against wire breakage, power failure, and power overheating.

3. Intelligent power management technology ensures the instrument always operates at minimum power, effectively saving energy and reducing heat generation.

4. High output voltage and wide measurement range.

5. The test current comes from a high-precision, high-current constant power supply, requiring no manual adjustment, and the test is fast and accurate.

6. The four-terminal wiring method effectively eliminates the influence of the test lead resistance on the test results.

7. Seven-inch high-brightness touchscreen color LCD, clear display even in strong light, full touchscreen operation, and free switching between multiple languages .

8. The instrument has a built-in perpetual calendar clock and power-off memory, which can store 9999 sets of test data for easy access at any time.

9. The instrument has Bluetooth communication, RS232 communication , RS485 communication and USB interface for computer communication and USB flash drive data storage.

10. Comes with a panel-mounted mini printer that can print measurement results in Chinese.

Technical Specifications

Test current: 5-200A

Measuring range: 0～100mΩ (50A) 0～50mΩ (100A)

      0～ 20mΩ （ 150A ） 0～ 20mΩ （ 200A ）

Resolution : Minimum 0.01µΩ

Accuracy: ± (0.5% ± 0.2 µΩ)

Power: 1000W

Operating mode: Continuous measurement

Operating power supply: AC220V±10% 50HZ

Operating temperature: -20 ～ 50 ℃

Relative humidity: less than or equal to 90%, no condensation.

External dimensions: 360*290*170 (mm)

Weight: Main unit 6.4 KG, cable box 9 KG