College】 【weak lift upward overspeed protection are those methods.

<br> 1. caused by the uplink speed of technical reasons to rely on traction elevator traction machine drive, the traction drive wheel and the friction between the car rope running, effectively closing the brake may be made to ensure a reliable car stopped. .Therefore, heavy emphasis on focusing on the amount greater than the case of the car, drive, traction and braking of any link failure may lead to the elevator upward speeding, will result in serious hoisting. .Therefore, causing the elevator are many reasons for the uplink speed: 1.1 brake spring relaxation, brake pads and brake wheel friction brake pads and wheel brakes overheating, resulting in decreased braking ability, stuck brake, the brake arm, axle pin fault .can not effectively lead to brake failure and so close; 1.2 traction machine spindle, bearings, gears, worm and other mechanical parts breakage or damage, a serious decline in traction; 1.3 traction condition is destroyed, the traction between the wheel and rope slip; 1.4 Electric Control .system failure, motor overheating burn, abnormal power voltage fluctuations caused by speeding and other reasons. .2. There is some upside in the elevator speeding speeding hidden causes of the above analysis, upward out of control due to brake failure is the most common, which was previously part of the main brake of the elevator is not used due to safety brake. .GB7588-1995 "elevator manufacturing and installation of safety norms" in the 12.4.2.1 article specifies that "all those involved in the brake wheel (or plate) the imposition of force installation of brake parts should be divided into two groups, and has the right size to meet: If a .group of components does not work, brake wheel (or disc) can still get enough braking force, so that the rated load of the car containing the retarder down. " .This in itself is a good provision, which requires the design of mechanical components of the brake must be redundant, so that when the work of a component failure, a reliable system of brakes still stop the elevator. .Unfortunately, GB7588-1995, this provision was suspended. .Since this provision of the stay of execution, resulting in some of the elevator brake there is birth defects in design, but also the manufacturing and non-use of safety brake to create the conditions. .The safety brake in part of non-use of the elevator upward out of control not only brought a hidden elevator, elevator safety circuit protection of all electrical safety switch effect is therefore greatly reduced, because the elevator electrical safety protection are ultimately made by a reliable safety gear .stop to play a role. .Currently in use on the elevator, a few such non-safety brake application, as a result of the use of such a brake the elevator upward hoisting accident occurred in many places in China. .The safe operation of the lift more and more attention today, that has birth defects of the non-safety brake should pay attention to. .Is the transformation of the brake or increase the uplink speed protection device, and or take other measures. .This not only involves economic, and security, but also the different structures involved in tractor, and a variety of structures between the elevator, it is difficult to generalize. .But no matter how, the uplink speed with a lift, especially the non-existence of the elevator safety brake risks should arouse our uplink speed elevators peers and relevant departments of the attention and taken seriously. .3. Uplink speed protection device should be encouraging and fortunate that the implementation of the newly promulgated in GB7588-2003, 12.4.2.1 shall be used as mandatory provisions, which will further promote the work of improving the reliability of the brake. .But also in the new standard, the uplink speed protection device as an important safety components are explicitly requested by the newly installed elevator, which will greatly reduce the newly installed elevator upward out of control accidents. .Car overspeed protection device is installed upstream in the traction drive elevator, in the elevator when the uplink speed to a certain extent, the system used to make the car stop or slow down an effective security device. .It is generally slow down the speed monitoring device and the installation of two parts. .Two-way governor usually detected as a speed car speed monitoring device is out of control. .Deceleration devices include safety gear, rope and safety brake clip, respectively, acting on the car or counterweight, rope systems (hanging rope or compensation rope) and the traction wheel. .Overspeed safety brake as the upstream protective device must be directly acting on the traction wheel or traction sheave axle closest to, the current in the absence of permanent magnet synchronous motor elevator machine room is usually used directly in the wheel brake traction .as the uplink speed protection. .The brake, mechanical structure design redundant, in line with the requirements of the safety brake, do not consider their failure. .And because it directly on the traction wheel, the traction machine spindle, bearings and other mechanical parts damage will not affect the effective brake system stopped. .Of course, it can not protect the destruction of the conditions, such as traction, traction slip between the wheel and wire rope caused by other reasons such as the uplink speed. .This raises the question: What upstream speed protection device what type of upstream speed should work? .According to GB7588-2003 "elevator manufacturing and installation of safety norms," the request, uplink speed protection devices need to brake failure and motor failure due to uplink transmission speed work. .Therefore, the current upward overspeed protection devices protect the elevator can not do all of the uplink speed. .<BR>.