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 repair, minor repair, tap changer position changes, fault inspection, and preventive tests, etc. The purposes are:

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

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

　　To check whether there are any broken points in the windings or leads;

　　To check the correctness of parallel branches, whether there is a situation where one or more breaks occur in a winding made of several parallel conductors;

　　To check for short circuits between layers and turns.

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

　　1. A microcomputer-controlled intelligent instrument that can store test results;

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

　　3. Advanced constant current power technology greatly reduces the volume, weight, and power consumption of the instrument, 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 printed results;

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

　　7. Large-capacity battery with three-stage charging circuit, screen displays battery level, and automatic shutdown at low voltage to prevent over-discharge;

　　8. This instrument is suitable for the 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 (length) ×260 (width) ×140 (height) 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