1. Calculation model
1.1 rotor modeling
This calculation uses DyRoBeS software, which simplifies the motor shaft into 48 units (49 nodes), loads the fan, guard ring, rotor winding, rectifier plate, etc. in the form of additional mass on the node at the corresponding position and inputs the moment of inertia. The motor is a 2-stage motor, and 24 lower slots are opened on the shaft section of the main body, which has a great influence on the bending moment of inertia of the horizontal and vertical axes, and is easy to generate vibration, in order to ensure the horizontal and vertical directions of the shaft. The bending moment of inertia is uniform, and the crescent is required to be opened on the large teeth to reduce the bending stiffness of the shaft in this direction.
2. Shaft system critical speed calculation
The critical speed calculation of the shafting is a basic part of the rotor dynamics analysis. Reasonable design of the critical speed of the rotor system is an important prerequisite for the safe and reliable operation of the unit.
2.1 Critical speed calculation results
According to the simplified model of the shafting system and the oil film support stiffness and damping of the bearing, the first three critical speeds of the shafting can be calculated. The calculation results are shown in Table 3. It can be seen from the calculation results that the first three critical speeds avoid the running speed of the motor from 3120 to 5040 rpm and have a certain safety margin.
2.2 bearing installation position calculation
This unit is a three-bearing structure. In order to ensure stable operation of the exciter end 3# bearing, the lower bearing bush needs to carry 300kg of supporting load. Therefore, the 3# bearing needs to be raised during installation, which can be calculated according to the static deflection and bearing load of the shafting system. The lifting amount of the 3# bearing is 1.9mm.
If you want to buy a fan motor, please pay attention to Ventilation Motor
