Product Overview:
It is a very important test item. In the "Regulations for Power Equipment Testing Procedures", it ranks second among transformer test items. The regulations stipulate that during transformer handover, major overhaul, minor overhaul, tap changer position changes, fault inspection, and preventive tests, the DC resistance of the transformer winding must be measured. The purposes are:
① To check the welding quality of internal wires and leads in the winding
② To check whether the contacts at each position of the tap changer are good
③ To check whether the winding or lead wires have any breaks
④ 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 wires
⑤ To check for short circuits between layers and turns
This product complies with the requirements of national standards GB6587-86 "General Outline of Environmental Testing for Electronic Measuring Instruments" and GB6593-86 "Rules for Quality Verification of Electronic Instruments".
Product Aliases:
DC resistance quick tester, transformer DC resistance quick tester, transformer DC resistance fast tester, inductive load DC resistance quick tester, inductive load DC resistance fast tester,
DC Resistance Tester Main Features:
1. Uses a high-speed 16-bit A/D converter, providing stable measurement data and good repeatability.
2. Automatic program-controlled current source technology, with a total of 1000 current gears set in the current source, automatically controlled by the internal microcontroller according to the measured resistance, achieving a relatively wide measurement range and measurement state without manual current gear switching.
3. Fast response speed. In the measurement state, the tap changer can be directly switched, and the instrument will automatically prompt, and the new resistance value will be displayed quickly.
4. Highly intelligent design with clever and advanced function settings, capable of automatically judging faults such as loose test leads or broken wires.
5. Comprehensive protection functions, reliably protecting the instrument from back electromotive force impact, with automatic discharge indication.
6. Can display measurement current and measurement time.
7. Intelligent power management technology effectively reduces internal heating of the instrument.
8. Can store 120 measurement data records, which are not lost upon power failure.
9. All Chinese menu and operation prompts, intuitive and convenient. 10. The digital resistance meter has high measurement accuracy, stable performance, clear display, wide measurement range, and strong anti-interference capability.
DC Resistance Tester Working Principle:
This tester adopts the typical four-wire measurement method to improve the accuracy of measuring resistance (especially low resistance). The program-controlled constant current source, program-controlled preamplifier, and A/D converter constitute the main body of the measurement circuit. The central control unit applies a constant, high-precision current to the external load under test by controlling the constant current source, and then processes the obtained data (including test voltage, current test current, etc.) to obtain the actual resistance value.
This instrument can store 255 test data records and can print all stored test data. The stored data will not be lost upon reset or power failure.
Technical Specifications:
1. Output four gear currents: 40A, 20A, 10A, 5A
2. Resolution: 0.1μΩ
3. Range: 20mΩ - 4Ω (5A gear); 10mΩ - 2Ω (10A gear);
0.2mΩ - 1Ω (20A gear); 0.1mΩ - 0.5Ω (40A gear);
4. Accuracy: 0.2%
5. Ambient temperature: 0~40℃
6. Ambient humidity: <90%RH
7. Working power supply: AC220V±10%, (50±1)HZ
8. Dimensions: 400×200×350mm
9. Weight: 13kg
Test current 5A, 10A, 20A, 40A
Measurement range
5A: 1μΩ~4Ω
10A: 1μΩ~2Ω
20A: 1μΩ~1Ω
40A: 1μΩ~0.5Ω
Measurement accuracy ±0.2% (full scale)
Display method: 128×64 dot matrix display, resistance displayed as 4 1/2 digits
Maximum resolution 0.1μΩ
Power supply: AC 220V±22V, 50Hz±2 Hz, fuse 5A
Maximum power consumption: 600W when test current is 40A
Working environment: Ambient temperature: 0°~40°
Relative humidity: ≤80%
Volume: 400╳200╳425 (mm)
Weight: 12kg with accessories
Precautions:
1. Before switching the tap changer of an on-load tap-changing transformer during testing, be sure to reset. After discharge is complete, the discharge indication sound ends, and the indication message disappears before switching the tap changer.
3. After the test, press the "Reset" button, and be sure to wait until the discharge indicator light goes out and the indication message disappears before turning off the power and disconnecting the wires.
4. During the test, avoid power outages or test clamp detachment.
5. Connect the ground wire before turning on the power, and disconnect the ground wire last after the test.
