NDZRT-20A Transformer DC Resistance Tester (Three-Channel)

Product Introduction

       The DC resistance of a transformer is a mandatory test item during the manufacturing process, factory acceptance tests, installation, commissioning tests, and preventive maintenance tests conducted by power departments. It effectively identifies manufacturing defects such as material selection, welding issues, loose connections, missing strands, broken wires in transformer windings, as well as problems that arise during operation. To meet the need for rapid measurement of transformer DC resistance, our company has developed this DC resistance tester leveraging our technical expertise. The instrument adopts advanced power supply technology, featuring a compact size, light weight, and high output current. Controlled by a single-chip microcomputer, it automatically performs self-check, data processing, and display functions, and includes automatic discharge and discharge indication. With high testing accuracy and user-friendly operation, it enables fast measurement of transformer DC resistance.

       This DC resistance tester employs a dual-power structure. For YN-connected windings of transformers with tap changers, it applies simultaneous three-phase excitation. The measurement system uses independent three-channel current sampling and independent three-channel voltage sampling, simultaneously measuring and displaying three-phase resistance values and three-phase unbalance rates. It significantly reduces working time, addressing the issue of prolonged DC resistance testing for each tap winding of power transformers, requiring only one-third of the time compared to traditional methods.

Product Features

☆、The instrument outputs high current and automatically selects the current, making operation simple.

☆、Three-channel measurement with real-time data acquisition, simultaneously measuring three resistance values and calculating the three-phase resistance unbalance rate.

☆、Capable of simultaneous three-phase measurement or single-channel measurement in the traditional way, with built-in temperature conversion functionality for convenience.

☆、Equipped with comprehensive protection circuits for high reliability.

☆、Includes a non-volatile perpetual calendar, clock, 80 sets of data storage, review, and printing functions.

☆、Allows setting printing information such as resistance phase sequence and tap position.

☆、Vertical chassis design for easy on-site operation.

☆、Features audible discharge alarm and clear discharge indication to reduce operational errors.

Technical Parameters

☆、Output current: Auto current selection (up to 20A)

☆、Output voltage: DC12V

☆、Measurement range: 0～100Ω

☆、Accuracy: 0.2%±0.5μΩ

☆、Resolution: ≥0.1μΩ

☆、Operating temperature: -20～40℃

☆、Environmental humidity: ≤80%RH, no condensation

☆、Power supply: AC220V±10%, 50Hz±1Hz

☆、Dimensions: 340mm (L) × 240mm (W) × 260mm (H)

☆、Net weight: 10.3kg