Vertical Thrust Bearing in hallow shaft pump question
Vertical Thrust Bearing in hallow shaft pump question
(OP)
I am new to vertical hallow shaft pump motors and have a newbie question here. Why are the thrust bearings mounted on the non drive end of the vertical hallow shaft pump motor ? Wouldn't you want the thrust bearing on the DE so it can support the weight of the motor? Is this done for assembly or maintenance purposes? Does it have to do with the fact it's a hallow shaft?
Realize it may be a dumb question, but would really like to understand why this is done. Please help
Realize it may be a dumb question, but would really like to understand why this is done. Please help





RE: Vertical Thrust Bearing in hallow shaft pump question
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(2B)+(2B)' ?
RE: Vertical Thrust Bearing in hallow shaft pump question
You can't compress a vertical pump shaft, especially hollow shaft, it will bow out and damage bearings. Same reason you don't want to operate a vertical pump in upthrust.
DE thrust bearing supporting the weight of the motor... You completely lost me there, sketch a free body diagram and see if you still have the question.
RE: Vertical Thrust Bearing in hallow shaft pump question
Steve
RE: Vertical Thrust Bearing in hallow shaft pump question
electricpete: I can see that. Coupling below the thrust bearing puts hallow shaft in tension so don't have issues with buckling. Coupling above thrust bearing puts shaft in compression so you would have issues with buckling.
SteveWag: Downthrust force might be beyond my comprehension level at the moment.
Thanks for the help guys!!! I'm starting to make heads or tails of this.
RE: Vertical Thrust Bearing in hallow shaft pump question
The hydraulic down thrust is a function of the mounting depth, diameter of the impellor(s), and the discharge pressure. All of the weight of the water AND the discharge pressure spread over the impellers, is counteracted by or supported by the vertical line shaft. This is why line shaft stretch is calculated at shutoff head.
Steve
RE: Vertical Thrust Bearing in hallow shaft pump question
=====================================
(2B)+(2B)' ?