Soya Electric is a professional R&D and production loop resistance tester manufacturer. The loop resistance tester produced by the company is widely acclaimed in the industry, and strives to build the most authoritative "loop resistance tester" high voltage equipment supplier. LX Body Kit,Side moulding,Door moulding,Side step,Roof rack,roof rail Guangzhou YS Auto Parts Co.,LTD , https://www.zjysapcn.com
Loop resistance tester, also known as transformer loop resistance tester, is mainly used to test the contact resistance of the high-voltage circuit breaker's moving and static contacts. The circuit breaker's conductive loop resistance mainly depends on the contact resistance of the moving and static contacts. The existence of the contact resistance increases. The loss of the conductor during power-on increases the temperature at the contact point. The magnitude of the value directly affects the current carrying capacity during normal operation, and affects the cut-off capability of the short-circuit current to a certain extent. It is also an important data reflecting the quality of the installation and maintenance work. . At present, there are mainly three test methods for loop resistance testers. The specific operations are as follows:
1. Bridge method: When using a double-arm bridge to measure the circuit breaker's conductive loop resistance, the measurement loop passes through a weak current, it is difficult to eliminate the oxide film with a large resistance, and the measured resistance value is large, and because When the current is small, it is difficult to form a contraction at the contact point of the contact, that is, the shrinkage resistance cannot be measured.
2. Voltage drop method: In the circuit under test, when a direct current is passed, a voltage drop will be generated in the loop contact resistance, the current value and the voltage value through the loop will be measured, and the contact resistance will be calculated. The testing process is cumbersome and manual calculation of measurement results has certain errors.
3, micro-European instrument method (loop resistance tester): The principle is the principle of voltage drop, but measurement, calculation and other aspects of the use of single-chip processing, greatly reducing the workload.
Loop resistance tester features:
1. High current: Using the latest switching power supply technology, it can continuously output large current for a long time, which overcomes the disadvantages of pulsed power supply's instantaneous current and can effectively break down the contact oxide film of the switch and get good test results.
2. High stability: Under severe interference conditions, the last digit of the LCD screen can be stabilized within ±1 word, the reading is stable and the repeatability is good.
3. High-precision: The use of dual high-speed 16-bit Σ-Δ AD sampling, the latest digital signal processing technology, the highest resolution of 0.01μΩ, is currently the only 0.01μΩ resolution and very stable contact resistance tester, performance Exceeded the imported high-current micro-ohmmeter.
4. Intelligent: Using imported high-performance CPU, the system automatically switches the range according to the signal size during the measurement to ensure the test accuracy of the product. 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: The key components are all imported components, and the temperature compensation circuit effectively eliminates the influence of the ambient temperature on the measurement results through the ingeniously designed temperature compensation circuit. The use of special connectors enhances the anti-vibration performance.
6. Powerful: The current can be freely selected in 50A, 100A, the test time can be arbitrarily set in 5s~599s, which overcomes the defects that other similar instruments can not set the measurement time or the continuous working time is too short, far exceeding the The performance of other similar instruments.
At present, the conventional QJ44 type dual-arm DC bridge is commonly used to measure the contact resistance in the power system, and the test current of this type of bridge is only mA, and it is difficult to find the defect that the cross-sectional area of ​​the return conductor is reduced. When measuring the contact resistance of the high-voltage switch conductive loop, due to the influence of the oil film and the oxide layer between the contacts, the measured value is a few times larger, and the contact resistance value cannot be truly reflected. To this end, the latest Ministry of Electric Power Standard DL/T845.4-2004 "Resistance measurement device general technical conditions: loop resistance tester" and the new version of the verification procedures JJG1052-2009 "loop resistance tester, direct resistance test procedures" to make measurements ( Isolation) The measured current of the contact resistance of switches, circuit breakers, etc. shall be not less than 100A DC, and the minimum current holding time shall not be less than 60S to ensure accurate test results.
The instrument's operation panel adopts ergonomic design and conforms to the operating habits. It adopts high-frequency switching power supply and digital circuit technology and is suitable for measuring the loop resistance of the switch control equipment. The test current adopts the DC 100A recommended by the national standard. The loop resistance can be directly measured under the condition of DC 100A. The test results are displayed on a large LCD screen, and there are functions such as data storage, output printing, and time setting. Another 50A is available for user selection; The set time 599S is much larger than the standard 60S. It is the only contact resistance tester with the resolution of 0.01μΩ and is very stable in China. The performance exceeds the imported high-current micro-ohmmeter. It meets the requirements of field high-voltage switch repair and high-voltage switch factory loop resistance test of power and power supply departments.
Designed for high and low voltage switch contact (loop) resistance, high precision measurement of the cable circuit DC resistance, the same applies to other occasions that require high current, micro resistance measurement.