1、 Product Overview
At present, the conventional QJ44 double arm DC bridge is widely used in the power system to measure the contact resistance, but the test current of this type of bridge is only mA level, and it is difficult to find the defect of reducing the cross-sectional area of the circuit conductor. When measuring the contact resistance of the conductive circuit of the high-voltage switch, due to the influence of the oil film and oxide layer between the contacts, the measured value is several times larger, which cannot truly reflect the contact resistance value. For this reason, the Ministry of Electric Power standard SD301-88 Code for AC 500kV Power Equipment Handover and Preventive Test and the new version of Code for Preventive Test of Power Equipment stipulate that the measured current of the contact resistance of circuit breakers and disconnectors shall not be less than DC 100A, so as to ensure accurate test results.
This instrument is designed according to the advanced electric power executive standard DL/T845.4-2004 of the People's Republic of China, using the combination of high-frequency switching power supply technology and digital circuit technology. It is applicable to the measurement of circuit resistance of switch control equipment. The test current adopts DC 100A and 200A recommended by the national standard. The circuit resistance can be directly measured under the current of 100A and 200A. The test results are displayed on a large screen LCD, with data storage, output printing, time setting and other functions. There are also 50A and 150A gears for users to choose. The instrument is accurate in measurement and stable in performance, meeting the requirements of on-site high-voltage switch maintenance of power and power supply departments and circuit resistance test of high-voltage switch plants.
2、 Purpose
It is suitable for high-precision measurement of contact (loop) resistance of high-voltage switch, as well as other occasions requiring high current and micro resistance measurement.
3、 Performance characteristics
(1) High current: advanced switching power supply technology is adopted, which can continuously output high current for a long time, overcome the disadvantage of instantaneous current of pulse power supply, and effectively break down the oxide film of switch contact, obtaining good test results.
(2) High stability: under the condition of serious interference, the last digit data of the LCD screen can be stable within ± 1 word, with stable reading and good repeatability.
(3) High precision: dual high-speed 16 bit Σ－Δ AD sampling, advanced digital signal processing technology, resolution of 0.01 μ Ω, the only one in China that can reach 0.01 μ The contact resistance tester with Ω resolution and very stable performance exceeds the imported high current micro ohmmeter.
(4) Intelligentization: The imported high-performance CPU is used, and the system automatically switches the measuring range according to the signal size during measurement, ensuring the test accuracy of the product. The over temperature protection circuit can automatically stop the output current when the instrument exceeds the set temperature to ensure the safe use of the instrument.
(5) High quality: all key components are imported components. The influence of ambient temperature on the measurement results is effectively eliminated through the ingeniously designed temperature compensation circuit. The use of military connectors enhances the anti vibration performance.
(6) Powerful function: the current can be freely selected from 50A, 100A, 150A, 200A, and the test time can be arbitrarily set within 5s~599s, overcoming the defect that other similar instruments cannot set the measurement time or the continuous working time is too short, far exceeding the performance of other similar instruments.
(7) Friendly human-computer interface: It is convenient and fast to input data by rotating the mouse. You can independently set the date and time of the instrument, save the measurement data in real time, and print the measurement results in real time.
(8) USB communication mode: it can communicate with the computer through USB data line and upload the measurement data to the computer for further analysis and processing by the tester.
(9) Easy to use: small size, light weight, easy to carry.
4、 Technical indicators
1. Measuring range: 0 ～ 2999.9 μ Ω
2. Resolution: 0~99.99, 0.01 μ Ω；
100.0~2999.9，0.1 μ Ω
3. Test current: DC50A, 100A, 150A, 200A four gear fixed output
4. Measurement accuracy: ± (0.5% rd+2d)
5. Continuous working time: 5s~599s
6. Display mode: large screen Chinese LCD
7. Communication mode: USB
8. Working power supply: AC220V ± 10% 50Hz
9. Overall power: 1200W
10. Maximum storage records: 200
11. Working environment: temperature - 10 ℃～ 40 ℃, humidity ≤ 80% RH
12. Volume: 380 × three hundred × 260 mm3
13. Weight: 8kg (excluding accessories)
