Product Introduction

       DC resistance testing of transformer windings is an essential test item after transformer handover, overhaul, and tap changer adjustment. By measuring the DC resistance of transformer windings, issues such as the welding or connection quality of leads, winding short circuits or open circuits, and the contact condition of tap changers can be detected. Previously, the QJ44 double bridge was used for DC resistance measurement, which required a long measurement time due to its milliampere-level current and had relatively low accuracy. To address these issues, reduce measurement time, and alleviate the workload of test personnel, our company developed this product.

       This product is a high-precision replacement for traditional DC single and double bridges. It adopts advanced switching power supply technology, making its measurement speed over a hundred times faster than that of bridges. The display section features a four-and-a-half-digit LCD for measurement results and a three-and-a-half-digit LCD for ambient temperature or test current values, overcoming the drawback of LED displays being difficult to read in sunlight. It also includes an automatic arc suppression function. The instrument offers fast measurement speed, high accuracy, intuitive display, strong anti-interference capability, compact size, low power consumption, stable and reliable test data, and is unaffected by human factors. It is equipped with a rechargeable battery pack (14.8V) and supports both AC and DC power, making it suitable for on-site and field testing.
       This product complies with DL/T 845.3-2004 "General Technical Conditions for Resistance Measuring Devices - Part 3: DC Resistance Tester." It is an ideal instrument for measuring the DC resistance of power transformers, large motors, transformers, and other inductive loads, as well as contact resistance of low-voltage switches, resistance of wires and cables, or weld interface resistance.

Product Features

☆、Fast testing speed: The instrument outputs a charging current of up to 3A, effectively compensating for the current inertia of large inductive equipment during measurement, accelerating core saturation, thereby shortening charging time and improving testing speed. It is hundreds of times faster than traditional single and double bridges.
☆、High accuracy: In addition to advanced four-terminal measurement, the instrument uses advanced constant current source technology, ensuring that the charging current for inductive loads remains relatively stable. It offers strong anti-induction capability and anti-interference performance, guaranteeing measurement accuracy. High-quality imported components ensure high accuracy and repeatability of measurement results.
☆、Wide measurement range: Resistance measurement ranges from 1μΩ to 20kΩ, covering a broad spectrum.
☆、AC/DC dual power supply: The instrument includes a built-in rechargeable battery pack, supports AC and DC power, and features a portable design for convenient use and carrying.

Technical Parameters

☆、Operating conditions:

       Ambient temperature: 0℃～40℃;

       Relative humidity: ≤85％RH.

☆、Measurement range:

      The instrument has seven ranges:

       1μΩ～20mΩ;

      20 mΩ～200mΩ;

       0.2Ω～2Ω;

      2Ω～20Ω;

      20Ω～200Ω;

      200Ω～2kΩ;

      2kΩ～20kΩ.

☆、Measurement accuracy: ±(0.2%+2d)

☆、Resolution: 1μΩ

☆、Constant current source:

      3A（1μΩ～20mΩ、20 mΩ～200mΩ、0.2Ω～2Ω）；

      300mA(2Ω～20Ω)；

      15mA（20Ω～200Ω）；

      1.5mA（200Ω～2kΩ）；

      150uA（2kΩ～20kΩ）.

☆、Operating voltage:

      DC：12V～16.8V；

      AC：220V.

☆、Power consumption：≤15W

☆、Dimensions：365×330×180mm3

☆、Weight：5kg（including test clamps and cables）