Electric single-girder crane trolley Common Problems

Electric single girder bridge gantry crane  is to hoist the crane hoisting mechanism, which means electric hoist trolley, its working principle is equivalent to hoist cranes. Because of its simple structure, easy to operate (mainly in the form of ground operations mainly), low cost, machinery, chemicals, light industry and other industries widely used. Because of this particularity of lifting machinery, ground operations often a person several roles, and also served as operations, company search, command tasks, there are many unsafe operating risks.

To guard against this type of crane lifting injuries occur, GB6067-2008 "crane safety regulations" and other relevant national standards has asked hoist must have safety devices, such as limit switch, end stops, buffers, safe braking devices, these security guards equipped to effectively improve the safety and reliability of  hoist crane  , but because of the design, manufacture produces its own defects and other reasons, hoist cranes security measures is still not perfect, according to the daily inspection experience found hoist cranes in the wrong phase protection, anti-broken shaft protection, buffer settings, etc., there are still defects or deficiencies.

Because hoist cranes conical brake three-phase asynchronous motors used as power plant, while the three-phase asynchronous motor rotation direction and phase sequence of the power supply on. When the power supply phase sequence is changed, the motor running direction opposite to the original direction, this time by operating the door flashlight "down" button, the spreader increased, and increase the limit position limiter ineffective, due likely to cause an accident, each Such cranes will occur due to wrong phase caused by the crushing rolls, hook group extrusion, wire rope lifting pull off such an accident. At present, China's production and widely used CD, MD electric hoist did not take the wrong phase protection measures (in the standard is to require electric hoist installed), in order to prevent wrong phase injury accidents caused by lifting the hoist crane electrical control system by adding the wrong phase protection, phase failure occurs when the power supply or the wrong phase, wrong phase protection functions, so that the total power contactors disconnect the power supply must be returned to normal after the  bridge gantry crane  can continue working. This will prevent the power of phase lead winch, but will also prevent motor phase operation were burned. Therefore, dislocation phase protector role is very reliable.

Electric hoist during operation, the wheel rim and wheel tread wear, wheel and rail gap increases, at this time if not promptly adjust the running clearance, electric hoist may be derailed, causing the lifting injuries; same time as the wheel axle assembly position particularity, axle cracks can not easily be found, when the crack is not effectively controlled, the axle may rupture, causing falling accident. To prevent the resulting electric hoist fall accidents can hoist a suitable location to additional anti-broken shaft protection device, when hoist derailed or broken shaft, the anti-broken shaft protection device can effectively suspended from the track, thus avoiding lifting injury accidents.

In accordance with GB6067-2008 "crane safety regulations" requirement, in orbit hoist to be fitted with a terminal buffer, but the installation location is not specified. At present, China uses electric hoist buffers generally installed in the middle of the beam, when the hoist running wheels collide with the buffer, the buffer has played the role of energy absorption. However, due to the special structure of electric hoist, wheel rim run collision with the buffer, in the role of inertia, the wear of the wheel rim so that the buffer is extremely serious, when the electric hoist running for some time, the buffer will lose the original Some design features, so that during the operation of electric hoist insecurity increases, the smooth running of electric hoist sharp decline. In order to prevent the occurrence of a malfunction, the installation location of the buffer can be selected in the lower surface of the beam, using the buffer and the lug plate suspended hoist collision cushion win effectively extending the life of the buffer.