Work type and weight of the crane are two different concepts

Work type and weight of the crane are two different concepts, the weight is big, not necessarily is heavy, the weight is small, also is not necessarily the light level. Such as water power station with the crane lifting weight of hundreds of tons, but very few use opportunity, is only used when installing unit and repair unit, the rest of the time is down there, so even though the weight is very big, but still belongs to the light level. And as the station yard gantry hoist gantry crane, while the weight is not big, but the job is busy, belong to the type of heavy work. Crane type of work and safety performance has a very close relationship. Lifting weight, span, lifting height of the same crane, if different type of work, in designing and steel crane, the safety factor is not taken by the same, or different parts model, size, specification. Brake, due to the different type of work, such as wire rope safety coefficient of different levels (light safety coefficient is small, heavy security coefficient), selected models is not the same. As is 10 t bridge crane, again for the work of the intermediate type (JC = 25%) of the hoisting motor power for N = 16 KW, for the heavy work types (JC = 40%) hoisting motor power is N = 23.5 KW.