‌  In the field of electric motors, the placement of positioning bearings in vertical motors is critically important and requires comprehensive consideration of multiple factors.

‌From the perspective of motor structure and force analysis:‌

• In horizontal motors, bearings primarily withstand radial loads, whereas in vertical motors, rotor gravity converts to axial loads. Typically, one end is fixed (positioning) to bear axial forces, thus requiring bearings capable of handling axial loads.

‌Selection of positioning bearing location is influenced by external loads on the shaft extension end:‌

• Example: In vertical pump motors, the shaft extension connects to impellers and faces radial impact from water flow. If the positioning bearing is placed at the lower (shaft extension) end, it must simultaneously endure rotor gravity and radial hydraulic forces, accelerating wear.
• ‌Case Study‌: Kenda Bearing served a pump manufacturer where improper positioning bearing placement reduced bearing life to 60% of the design value. After relocating the positioning bearing to the upper end (with the lower end floating), service life extended to 1.5 times the original.

‌Maintenance accessibility is equally critical:‌

• Positioning bearings endure combined loads (axial + radial), demanding frequent maintenance. For vertical motors in harsh environments (e.g., mining equipment), maintenance complexity increases if the positioning bearing is on the non-shaft-extension end, as it may require disassembling auxiliary components like fans or covers.

‌Conclusion:‌
There is no universal answer for positioning bearing placement in vertical motors. Optimal selection must integrate motor structure, shaft-end load conditions, and maintenance feasibility to ensure stable and efficient operation.