LW31-252 GCB (HMB-4 Hydraulic Spring Mechanism) User Reports Work Well

The experience is forgiven, but the overall performance of the circuit breaker is not a problem. b is a schematic diagram of the opening action to adjust the bending deflection of the temperature sensing element. The push rod I and the push rod 2 are coupled by the shaft pin 3 to form an "open and close drawbar", which is placed on the push rod 1 by rotating the eccentric 4 The slider 5 translates and pushes the bump 6 located on the push rod 2, so that the I and 2 open and close, that is, the bending deflection of the temperature sensing element is changed. The design structure is more complicated, but the action is more stable. The electromagnetic tripping can be designed to be single-phase independent adjustment, or it can be designed as three-phase linkage adjustment. The former has higher motion accuracy. 3 If the structure permits, it can also be designed as single-phase and three-phase linkage adjustment, but this will greatly increase the design. The complexity, the product cost increases accordingly, the adjustable thermal tripping needs to be independently adjusted in a single phase, and the design structure is very complicated, so it is generally designed to be three-phase linkage adjustment, which can meet the requirements of the general distribution system. .

Fourth, the adjustable tripping current setting range as a protective molded case circuit breaker, not only requires it to quickly cut off the faulty line, but also must match the overload capacity of the protected appliance to prevent The necessary tripping causes the power supply to cut off the power distribution equipment and the line. It can have an overload capacity of 1.3fn no more than 2 hours, and the motor load has an overload capacity of 1.2/n no more than 2 hours. The long delay of the molded case circuit breaker The purpose of current adjustment is to adapt to the change of load capacity and load nature of the power distribution system. It can be adjusted by the user as appropriate, so that the protected equipment is in the optimal state of operation, and the adjustable long delay current range of the electronic tripping Wide, generally can be set in the range of 0.41.0 / n, and the adjustable long delay current range of the thermomagnetic circuit breaker is relatively smaller: because the free end bending deflection of the bimetal element can not be too large, otherwise it will Affects the repeatability of the trip time. Generally, the long delay current of the adjustable thermal tripping is set according to the range of 0.71.0/n or 0.8~1.0fn. The instantaneous tripping of the circuit breaker is a large overload or short circuit when the protected electric circuit or equipment is generated. When the current is protective, the short-circuit current can reach 20/n or more when the electrical equipment is short-circuited in the near area (that is, the metal direct short-circuit); and some insulation resistance caused by insulation aging, insulation moisture, conductive dust, etc., is greatly reduced. Even the overcurrent generated by the dielectric breakdown is much smaller than the accidental short-circuit current, but it is still enough to cause damage to the power distribution system. The electromagnetic trip must act quickly and effectively, causing the circuit breaker to cut off the main circuit. Of course, the instantaneous trip current should not be set too small. In principle, the starting current that can avoid the motor load is subject to change. Generally, the adjustable instantaneous tripping current range can be in accordance with GB14048.2. The second-language thermal-magnetic adjustable tripping molded case circuit breaker has broad development and application prospects: so far, such products are still rare in China. , H series (HKB-250, H Shanghai Electric Power Company, July 2008, 4 type hydraulic spring mechanism) produced by Shanghai Huatong Switch Factory, a total of 15 units for Zhujiazhuang 22 () kV substation (7 units) and Cao 220kV substation (8 sets) 屮The above products were delivered in February 2001. After installation and commissioning on site, they were put into operation in October 2001. LW31 8-252 SF6 circuit breaker was introduced to ABB ELFSP4. -丨 technology, and equipped with ABBCalorEmag's advanced HMB-4 hydraulic spring mechanism, the technical performance is excellent, the installation and commissioning work is simple and smooth, the service is good, the action is normal after putting into operation, the performance is stable, and it can meet the unmanned technology of the above two power stations. Claim.

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