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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 programmable constant current source, programmable 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 mode: 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
Product Overview:
It is a very important test item. In the "Regulations for Power Equipment Testing", 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 testing, the DC resistance of the transformer winding must be measured. The purposes are:
① Check the welding quality of internal wires and leads in the winding
② Check whether the contact of each position of the tap changer is good
③ Check whether the winding or lead wire has any broken points
④ 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
