Thrust Rating

Vertical Thrust Rating

Thrust ratings that are listed in the Modified Vertical Motors Catalog usually handle most specific purpose requirements for high thrust or normal thrust applications. Motors used for pump applications may require slightly higher thrust requirements for short periods or continuously, dependent upon the application.

Normal and medium thrust motors have that advantage of being able to carry thrust in both directions. This is accomplished by using a deep-groove ball bearing and clamping the bearing. The deep-groove ball bearing is used in high thrust motors as a guide bearing and for momentary upthrust.
High thrust vertical motors use the angular contact bearings that are capable of continuous thrust in only one direction. If the possibility exists of continuous thrust up-and-down then two bearings, back-to-back can be used.

For thrust loads above 175% thrust capacity the spherical roller thrust bearing has been developed. U.S. MOTORS® brand turbine pump motors employ spring loading of spherical bearings to insure that the bearing will not be damaged during the period of time in which pump normally exerts momentary upthrust. This bearing requires more oil circulation than ball bearings, and is taken care of in the design of the motor.