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 repairs, minor repairs, 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-out wires have any breaks
④ To check the correctness of parallel branches, and whether there is a situation where a winding made of several parallel wires has one or more broken 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 rapid tester, inductive load DC resistance quick tester, inductive load DC resistance rapid tester,
DC Resistance Tester Main Features:
1. Adopts high-speed 16-bit A/D converter, with 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, thereby achieving a relatively wide measurement range and measurement state, without the need for 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 soon.
4. Highly intelligent design, with ingenious and advanced function settings, can automatically judge faults such as loose test leads or broken wires.
5. Complete protection functions, reliably protecting the instrument from the impact of back electromotive force, with automatic discharge indication function.
6. Can display measurement current and measurement time.
7. Intelligent power management technology can effectively reduce internal heating of the instrument.
8. Can store 120 measurement data, which will not be lost after 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 ability.
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 and can print all stored test data. The stored data will not be lost when the instrument is reset or powered off.
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, be sure to reset. After discharge is completed, wait until the discharge prompt sound ends and the prompt 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 prompt 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.
