Vertical motors are a common installation type in industrial motors. Their electrical differences compared to horizontal engines are not significant, but they do present some structural disparities.
In terms of bearing selection, there are specific considerations to take into account for both vertical and horizontal motors.
Bearing load
For the clamping end bearing, the weight of the rotor in a vertical motor constitutes its axial load. In the absence of any other external radial loads, the radial load imposed by the engine air gap deflection becomes the bearing radial load.
It is crucial to avoid scenarios where the load supported by the free end bearing is less than the minimum load required for the bearing.
Bearing configuration
The clamping end bearing must be chosen to withstand axial loads. It is worth mentioning that even without external load, this axial load would be greater than that of a horizontal motor.
Common types of bearings used in vertical motors for the locating end include deep groove ball bearings, angular contact ball bearings, spherical roller bearings, tapered roller bearings, and spherical thrust roller bearings.
In large engines, tapered roller bearings require checking the elastic deformation of their housing under massive thrust.
In vertical engines, the correspondence between the located end, free end, and shaft extension and non-shaft extension ends must be determined based on various maintenance conditions.
Lubrication and refilling of lubricant
In vertically mounted engines, due to the action of gravity, the lubricating grease tends to flow to one side, leading to possible bearing lubrication problems. According to general lubrication recommendations, vertical motor bearings mainly opt for grease with a slightly higher viscosity, such as NLGI 3 grease. Furthermore, the lubricant replacement interval should be halved compared to horizontal motors .
Considering the effect of gravity, the grease needs to be injected through the upper end of the bearing housing and expelled through the lower end. This approach ensures that the newly added grease can effectively penetrate the bearing.
Testing aspect
Bearings are selected based on the operating conditions of vertical motors, therefore testing must also be carried out vertically. Otherwise, at best, testing the bearing for vibration and noise will not correspond to actual operating conditions. In the worst case, the bearings can be burned, especially when a single row angular contact ball bearing is used as the positioning end.
Transport Aspect
During storage and transport, vertical motors must be transported vertically, according to their operating mode. For small general-purpose vertical motors internally equipped with deep groove ball bearings, no special considerations are required for their storage and transportation.
However, if a single row angular contact ball bearing is used at the locating end of the motor, it is crucial to secure the shaft during transportation to prevent the bearing from becoming dislodged, thereby preventing possible damage.
