I. Overview

Transformer DC resistance is a mandatory test item in transformer manufacturing, including semi-finished and finished product factory tests, installation, maintenance, tap changer modifications, commissioning tests, and preventative tests by the power sector. It effectively checks for manufacturing defects and potential operational hazards such as material selection, welding quality, inter-turn short circuits, loose connections, missing strands, and broken wires. To meet the need for rapid DC resistance measurement of transformers, our company has developed a new generation of DC resistance testers leveraging our technological advantages. This instrument uses new power supply technology and features small size, light weight, and high output current. For on-load tap-changing transformers, it allows direct tap adjustment without discharging, significantly reducing working time. For large-capacity transformers, the instrument can also use a magnetizing method to quickly and accurately measure the DC resistance of the windings. After the DC resistance test, the instrument's built-in demagnetizing function can reduce residual magnetism in the transformer, minimizing the need for subsequent processing.

The entire instrument is controlled by a microcontroller, automatically performing self-testing, data processing, and display functions. It also features automatic discharge and audible discharge alarm indication. This instrument provides stable and highly accurate test data, is easy to operate, and has comprehensive protection functions , making it an ideal device for on-site measurement of the DC resistance of transformer windings and high-power inductors.

II . Functional Features

Intelligent interconnection and convenient data management : In addition to supporting traditional USB data transmission, it also adds Bluetooth , RS232 and RS485 communication functions, which can realize wireless connection and remote control with mobile APP, computer, console and other devices , greatly improving work efficiency.

High-performance power supply technology enables fast and accurate measurements : the maximum output voltage is 24V, supports multiple current ranges, and can automatically select the optimal range according to the load; combined with the magnetic auxiliary measurement method, it significantly improves the speed and accuracy of high resistance measurement; it can directly switch the on-load tap changer in DC resistance measurement mode, and the instrument automatically refreshes the data.

Multiple safety protections for greater peace of mind : To ensure the safety of operators and equipment, a multi-layered protection system has been constructed. Core protection functions include back EMF surge protection, automatic discharge, AC380V incorrect connection protection , and input power overvoltage protection ; coupled with audible alarms and clear discharge indicators, this effectively prevents equipment damage and personal injury risks caused by misoperation or sudden changes in the external environment, making the testing process safer.

User-friendly design, intuitive and efficient operation : 7-inch high-brightness color touchscreen, clearly visible even in strong light, supports Chinese and English switching; convenient touch input, graphical interface design, intuitive, efficient, and easy to understand; equipped with arbitrary temperature conversion function, built-in mini printer, and can translate printing results into Chinese.

Massive data storage : Built-in perpetual calendar and power-off storage, capable of saving 60,000 sets of data for easy access at any time, while also supporting export via USB flash drive and wireless Bluetooth .

Integrated design with powerful functions : It integrates magnetization measurement and demagnetization functions, and demagnetization after measurement can significantly reduce residual magnetism; the whole machine is controlled by a high-speed single-chip microcomputer, which is small in size, has a large output current, good repeatability, and strong anti-interference ability.

Wide voltage input and AC/DC dual source compatibility: In terms of power supply adaptability , the input power supply supports dual-mode power supply of 110 ~ 240VAC or 155 ~ 340VDC, which is compatible with global power grids and DC panels of substations. With a wide frequency design of 47 ~ 63Hz, it ensures stable operation under voltage fluctuations.

III. Main Technical Specifications