If a single speed, when the head is less than 51m, pump efficiency will drop more than 3%. And when the head is less than 42m, pump efficiency will be lower, except the need for greater force into the outer, inner suction pipe flow condition seriously deteriorated, exacerbated by the phenomenon of cavitation, the unit will generate a lot of vibration and noise and affect the normal operation, so that had to limit the number of running at low lift, thus affecting the economic benefits of the project. Furthermore, as a single speed, pump working conditions and turbine speed is not a good match.
The stator pole-changing commutation switch: a stator pole commutation switch Variable Total 6, selection of Panyu switch factory in Jiangsu vacuum high voltage switch, a smaller size. Pole-changing switch disposed on the external walls of the machine pit. Commutation switch arrangement in the bus corridor. Should institute the requirements, commutation switch doubles as isolating switch. Stator Lifting: stator core laminations after loading pressure between the installation is complete, use lifting holes are provided in the stator frame ring rib plate with whole stator wire rope lifting, lifting points are located aim lower ring plate, first, because the power station underground powerhouse, should be minimized lifting height, lifting height of the rotor so that it is similar to the second is to reduce the distortion in order to meet the stator, while lifting easier. Double trolley overhead crane inside the plant for 2 × 125t, the stator lifting weight 200t, the maximum lifting height of 6000mm.
Rotor brake rotor magnetic pole throw using size pole pole-changing, all-round 40 poles from 28 large and 12 small pole pole composed lose four small poles 36 poles running. Using seven large pole with three small very purpose is to ensure that the harmonic structure rather extreme measures before and after the change.
Under the yoke with a detachable multi-block brake ring. Pole: pole cores in 2mm high quality steel sheet punching NKHA-590 laminated together, the size of the magnetic pole points in two sizes, the size of the pole pole body width, different turns. Due to the need pole distribution arrangement, a small pole in eight extremely single T-tailed, four great double T tail, large pole is full of double-T tail. Magnetic coils heptagon flat copper winding is made and Class F insulation. Rotor pole-changing switch: a rotor pole-changing switch altogether two, still use vacuum high voltage switch, small size, arranged on the machine pit facade. Rotor shaft using lifting lifting, lifting the weight of 230t (including lifting axle), lifting height 6105mm.
