Measuring the DC resistance of transformer windings is a very important test item. In the "Regulations for Power Equipment Testing," it is ranked second among transformer test items. The regulations stipulate that the DC resistance of transformer windings must be measured during transformer handover, major repairs, minor repairs, tap changer position changes, fault inspections, and preventive tests. The purposes are:

　　To check the welding quality of internal conductors and leads in the windings;

　　To check whether the contacts at each position of the tap changer are in good condition;

　　To check for any broken points in the windings or leads;

　　To check the correctness of parallel branches, whether there are one or more broken circuits in windings made of several parallel conductors;

　　To check for short circuits between layers and turns.

　　II. Product Features of GWZRC-3A DC Resistance Tester:

　　1. An intelligent instrument controlled by a microcomputer, capable of storing test results;

　　2. AC/DC power supply, portable design, easy to use and carry;

　　3. Advanced constant current power supply technology greatly reduces the instrument's size, weight, and power consumption, further shortening measurement time and ensuring more stable and reliable measurement data.

　　4. Large-screen LCD display with blue backlight, suitable for all-weather use;

　　5. Built-in micro printer for direct output of print results;

　　6. Built-in high-volume buzzer with audible prompt function.

　　7. Large-capacity battery, three-stage charging circuit, screen displays battery level, automatic shutdown at low voltage to avoid over-discharge of the battery;

　　8. This instrument is suitable for measurement and analysis of inductive, low-resistance values such as various power transformer and mutual inductor windings.

　　III. Technical Parameters of GWZRC-3A DC Resistance Tester:

　　Range and Test Current 0～20mΩ--3A

　　0～200mΩ--3A

　　0～2Ω--3A

　　0～20Ω--0.3A

　　0～200Ω--0.03A

　　0～2kΩ--0.003A

　　Accuracy 0.2%±2 digits (25±2℃)

　　Dimensions 360 (L) ×260 (W) ×140 (H) mm

　　Weight Approximately 6kg

　　Power Supply AC220V±10% Frequency: 50Hz±5%

　　Operating Environment Temperature: 0～40℃

　　Relative Humidity: ≤80%

　　Safety Performance Insulation Resistance: ≥2MΩ

　　Leakage Current: ≤5mA