The DC resistance of each circuit of the circuit breaker includes the resistance of the bushing conductor, the contact resistance between the conductor pole and the contact, and the contact resistance between the contact and the contact. This is actually a measure of the contact resistance of moving and static contacts. Operating circuit breaker contact resistance increases, the contact will make the normal operating current overheating, especially when the short-circuit current through the fault, the contact may cause local overheating, in severe cases may burn the surrounding insulation and cause contact melting Bonding, thus affecting the tripping time and breaking capacity of the circuit breaker, and even refuse to move. Therefore, the installation of circuit breakers, the size of repair and cover up the fault current after 3 times, are required for this test. experiment method Resistors for each phase of the circuit breakers shall be measured between the ends of each of the two bushing tubes under DC voltage. The measurement method is the same as the normal DC resistance measurement method, that is, the bridge method or the voltage drop method can be used. Precautions In addition to the general considerations for DC resistance measurement, observe the following characteristics of the circuit-breaker: (1) Since the DC resistance of the conductive circuit of each phase of the circuit breaker is very small, it is generally measured in micro-ohms. Therefore, when using the bridge method to measure, the double-arm bridge must be used. When measuring with the voltage drop method, Enough capacity DC power supply, while selecting the appropriate millivoltmeter and ammeter. (2) During the test, special attention must be paid to eliminate the influence of the measuring lead and the resistance of the joint. The lead should have enough cross-sectional area, and should be as short as possible. The current and voltage lead joints must be strictly separated. (3) The circuit breaker should be tripped several times before the measurement. If it is a circuit breaker with electric closing, it should be measured after the electric closing. (4) In order to protect the measuring instrument, in the measuring process, the circuit breaker tripping mechanism should be stuck to prevent sudden tripping in the test, damage to the instrument. (5) Measure at least 3 times per phase, whichever is the average, and if there is any suspicion about the measurement result, test several times. Analysis of the results to determine Circuit breaker each phase conductive circuit DC resistance measurement results should be consistent with the provisions of the manufacturer. The measured results compared with the previous results, if more than doubled, the contacts should be checked; when the difference between the three phases, it should attract attention, you must double-check for processing. If the measurement results exceed the manufacturer's standard, the breaker can be tripped once and re-measured. If it is still too large, the cause should be identified and dealt with. Select regular products is very important, Wuhan Huadian twenty years specializing in high and low voltage power transmission and transformation test, series resonant voltage, insulation withstand voltage test, transformer testing, circuit breaker testing and other equipment production, sales, research and development and solutions provide. For nearly a hundred power engineering company, the installation of electric power company's commitment, bearing, a test provided a high-quality test equipment and technical solutions services, has been praised by users. 20 years of accumulated experience in the industry will provide more reliable help to users, Wuhan Huadian Transtech Services is willing to work with you to win-win, grow together! Iron Wire
Over 30 years of experience covers dozens of product line.
Anping Sanxing Wire Mesh Factory was established in 1990,which is a professional manufacturer of Welded Wire Mesh , welded wire mesh panel, Hexagonal Wire Mesh, CHAIN LINK FENCE , Crimped Wire Mesh, Stainless Steel Wire Mesh, Fence netting, expanded metal mesh, Window Screen , galvanized Square Wire Mesh , Fiberglass Mesh , grating mesh, Barbed Wire , Razor Barbed Wire, Galvanized Wire , black annealed wire, bailing wire, cut wire etc. Our production are widely used in industry agriculture, cultivation, construction, transport and mining. By now we have already established business relations with more than 100 customers from Southeast Asia, Asia, Europe, Middle East, Africa, and quadruple the sales amount and customers annually.
There are 5 branch companies take 19000 square meters,165 skilled and 10000 tons capacity monthly to handle different volume orders.
We have a perfect sales team with basic qualities of responsible for customer, non-stoppace of the pursuit of progress, and provide good after-sales service. More than 15 oversea sales speaking English and have more than 4 years work experience by average.
Our quality management system conforms to the ISO 9001,ISO14001 and SGS guideline and we check each step in the production process, We purchase raw materials from well known manufacturers in china, and inspect material before warehousing.Our 6 inspection equipments the quality department bringed in 6 insepection equipments and conducts predelivery inspections for final products.
We are confident in our products with good performance and favorable price.We stick to 4 principles of quality,price,intergrity and service which are consistently implemented throughout the sales.
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