Talking About The Structure Of Hydro-generator-rotor
Author: source: date: 2020-06-08 10:25:33
Previously, we introduced what the stator of a hydro-generator is and what it does. So this time we will introduce another important component of the hydroelectric generator-the rotor. The rotor is the main component for converting energy and transmitting torque in the hydroelectric generator. It is generally composed of the main shaft, rotor support, yoke, magnetic pole and other components. The following are introduced one by one.
The function of the main shaft is to transmit torque, and it should have certain strength and rigidity.
The main shaft is generally made of 35, 40, 45 or 20SiMn steel. Small-capacity hydroelectric generators generally use solid forged solid shafts, and some use seamless steel tubes as shafts; large and medium-sized generators use solid forged hollow shafts.
The magnetic pole is a magnetic induction component that provides an exciting magnetic field. It is composed of magnetic pole core, coil, upper and lower supporting plates, pole body insulation, damping winding and steel pad. The pole core is divided into solid and laminated structure. The rotors of medium and small capacity high-speed hydro-generators are often made of solid magnetic poles and are integrally forged or cast. For small hydro-generators with a rotational speed greater than or equal to 750r/min, the magnetic pole iron core and the rotor's yoke and the main shaft are often forged and processed. The magnetic pole fixing method usually adopts screw, T tail and pigeon tail structure.
Yoke and rotor bracket
The role of the yoke is to form a magnetic circuit and fix the magnetic pole. The role of the rotor bracket is to fix the yoke. For small and medium-capacity hydroelectric generators with a stator core outer diameter of less than 325 cm, the yoke can be made of cast steel or a full-round thick steel plate, and no special rotor bracket is required. For a hydroelectric generator with a large stator core diameter, the yoke is connected to the main shaft through the rotor bracket. The outer edge of the yoke is machined with T-tail, pheasant tail groove or screw hole to fix the magnetic pole.
The frame is the supporting part of the vertical-axis hydroelectric generator where the thrust bearing, the guide bearing, the brake and the oil receiver of the hydraulic turbine are installed, and it is the more important structural part of the hydroelectric generator. The frame is composed of a center body and a support arm, which are generally welded with steel plates. The center body is in the form of a disk, and the support arms are mostly in the form of I-beams. The racks are divided into upper and lower racks according to their location, and are divided into load racks and non-load racks according to the bearing nature.
Thrust bearingsThe composition and function of the thrust bearing The thrust bearing is a mechanical structural component that uses the principle of liquid lubrication and load bearing. It is mainly composed of bearing seats and supports, bearing pads, mirror plates, thrust heads, oil grooves and cooling devices. Its main function is to bear the full weight and water thrust of the rotating part of the vertical axis hydroelectric generating set, and transmit these loads to the load frame.
Thrust bearing classification
Thrust bearing support structure mainly includes elastic pad support type, rigid anti-weight bolt support type, elastic oil tank support and balance weight support type. The elastic pad support type is only used for small-capacity vertical shaft generators; the elastic oil tank support and balance block support type are used for large and medium-sized generators; the thrust bearings of small and medium-sized hydroelectric generators are generally
The thrust head is the component that bears and transmits the axial load and torque of the unit. Most are fixed on the main shaft with flat keys and snap rings, and some are fixed on the main shaft by the hot sleeve method. The thrust head should have sufficient rigidity and strength to withstand the bending moment generated by the axial thrust of the unit, so as not to cause harmful deformation and damage.
The role of the tray is to reduce the deformation of the bearing shell. In addition, the axial flexibility of the pallet has a certain load balancing effect during operation. The material should be high-strength materials that can withstand greater bending stress.
Insulation pads are usually installed under the bearing seat or between the thrust head and the mirror plate coupling surface to cut off the shaft current loop, protect the bearing pad working surface, and play the dual role of insulation and axis adjustment.
Oil circulation cooling
There are two types of bearing oil circulation cooling methods: internal circulation and external circulation. The oil circulation cooling method of small and medium-sized hydroelectric generator bearings is generally internal circulation.