2.6 Cranes in Main Powerhouse

2.6.1

Appropriate slow-speed overhead crane with single trol ley or double trolleys or other type of crane may be selected according to the powerhouse conditions.

The rated hoisting capacity of the crane shall be determined in accordance with the total weight of the heaviest piece of the E&M equipment and the lifting device,referring to the standard hoisting capacity series of crane.The hoisting height of the crane shall meet the requirements for the unit installation and maintenance.

2.6.2

The number of cranes in the main power house shall be determined by technical and economic comparisons according to the layout of powerhouse,the number of units and hoisting mode for the heaviest piece of the E&M equipment,and the requirements of unloading,installation schedule and maintenance.

2.6.3

When 4 or fewer units are installed in the hydropower plant,the working class of crane should be A3.And if more than 4 units are installed and one crane is applied,the working class should be A3-A4.

2.6.4

Drag feed devices shall be installed at both ends of the crane rails.

2.6.5

After the crane is erected in main powerhouse,the tests of no-load,static load of the 1.25 times of the rated hoisting capacity and dynamic load of 1.1 times of the rated hoisting capacity shall be carried out.

If it is difficult to implement the static and dynamic load tests mentioned above,the dynamic load test may be carried out on the hoisting and braking mechanism by reducing the pulley block ratio.

For overhead crane with two trolleys,dynamic load test may be performed on each trolley respectively.