ZXR-5A：High-Precision High-Speed Solution for Power Equipment Low Resistance Measurement

1. Introduction

In power systems, power transformers are the core assets for energy transmission and voltage conversion. DC resistance measurement of transformer windings is a mandatory and critical diagnostic test in factory inspection, site handover, preventive maintenance, and fault diagnosis. This test enables technical personnel to identify latent defects including poor welding of winding leads, inter-turn short circuits, abnormal contact of tap changers, and loose connection of conductive parts, which can otherwise lead to equipment overheating, insulation degradation, and even catastrophic failures.

Traditional measurement methods, such as Wheatstone bridges and Kelvin double bridges, have prominent limitations when testing large inductive loads like power transformer windings. These methods suffer from extremely long charging time due to the current inertia of inductors, poor anti-interference performance in complex substation electromagnetic environments, and unavoidable measurement errors caused by lead wire and contact resistance. To address these industry pain points, the ZXR-5A DC Resistance Tester is developed to deliver a highly efficient, accurate, and field-adaptable solution for low-resistance measurement of inductive power equipment.

2. Core Technical Features and Design Advantages

2.1 Ultra-Fast Measurement with Inertia Compensation Technology

The ZXR-5A provides a maximum output charging current up to 5A, optimized for the characteristics of large inductive loads. It adopts advanced linear current compensation technology, which effectively offsets the current inertia of large inductors, accelerates the core saturation process of transformers, and drastically reduces the charging time required for stable measurement. Compared with traditional single and double bridge instruments, the test speed of the ZXR-5A is hundreds of times faster, which significantly improves on-site test efficiency and reduces the operation intensity of technical personnel, especially critical for time-limited outage maintenance tasks.

2.2 High-Precision Measurement with Four-Terminal Sensing Architecture

To guarantee reliable and accurate measurement results, the ZXR-5A integrates advanced four-terminal (Kelvin) measurement technology and a high-stability constant current source system. The four-terminal measurement architecture eliminates the inherent measurement errors caused by lead wire resistance and contact resistance, which is a major limitation of traditional two-terminal measurement methods for low-resistance testing.

Meanwhile, the precision constant current source maintains a highly stable charging current for inductive loads throughout the entire test process, granting the instrument excellent anti-sensing capability and strong anti-interference performance in harsh on-site electromagnetic environments. The instrument is assembled with imported high-quality components, which not only enhances measurement accuracy, but also ensures superior repeatability of test results in long-term field operation.

2.3 Field-Adaptable Design and Operational Safety

The ZXR-5A features a computer-controlled interface with a large-screen backlit English LCD display, delivering a user-friendly human-computer interaction experience. Real-time clear prompts for the measurement process and instrument operating status eliminate the need for operators to memorize complex operation procedures.

For flexible field application, the instrument supports dual AC and DC power supply: it is equipped with a built-in 14.8V/2.2Ah rechargeable lithium-ion battery for outdoor operation without grid power, and is also compatible with AC220V/50Hz(±10%) mains supply. With a compact dimension of 350×260×140mm and a weight of only ~3kg, the portable design enables easy carrying and operation in various test scenarios.

In addition, the instrument is designed with comprehensive protection mechanisms, including overvoltage protection and anti-back-electromotive force (back-EMF) impact protection, to ensure the safety of both the instrument and operators during inductive load testing. An optional panel-mounted printer is available for quick printing and archiving of measurement results for traceability.

3. Key Technical Specifications

表格

4. Application in the Power Industry

The ZXR-5A DC Resistance Tester is specially designed for low-resistance measurement and analysis of inductive components in the power industry, with its core application being winding resistance testing of all types of power transformers. Its high-speed measurement capability drastically shortens the test duration for large-capacity power transformers, while its high-precision performance ensures accurate detection of minor defects that may threaten equipment safety.

Beyond transformer testing, the instrument is also applicable to low-resistance measurement of other inductive power equipment, including reactors, current transformers, and loop resistance testing of high-current switchgear, providing a versatile test solution for power system technical personnel in both laboratory and field environments.

5. Conclusion

The ZXR-5A DC Resistance Tester overcomes the key limitations of traditional low-resistance measurement methods in the power industry, integrating high-speed current inertia compensation, high-precision four-terminal measurement, and field-adaptable portable design. It provides power system technical personnel with an efficient, accurate, reliable, and easy-to-use test tool for inductive low-resistance measurement. The instrument can significantly improve the efficiency of on-site maintenance and diagnostic tests, enhance the accuracy of defect detection, and thus support the safe, stable, and reliable operation of power equipment and power systems.

GDZX is a manufacturer of power detection equipment, offering a diverse range of products with comprehensive models and providing professional technical support. Contact us at +86-27-6552607 or +86-17396104357.Website: http://en.gdzxdl.com/