HIGH VIBRATION IN VERTICAL PUMP

Dear Rohit,

As per my observation multiples of 25Hz frequency present in spectrum while in coupled and decoupled. And pump side vibrations are not high and 13Hz frequency observed while in coupled condition and its value is high at motor side but it has not presence in decoupled spectrum.

I suspect motor fault rather than pump.I did not check bearing frequency .

 

 

Walt Strong posted:

Can you describe FAT Product Pump? Type of pump? Speed reducer? Shaft coupling type? I am not sure if your machine is a simple direct drive centrifugal pump or something else.

Walt

 

 Sir,

thank's for responding...

It is the simple vertical centrifugal pump with grid type coupling.

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Dear Rohit,

Your pump might have bushes for connecting multiple shafts. These bushes sometimes generates subharmonics due to rubbing or increased clearances. Though the motor solo run vibrations are not high i think you might go for pump bush inspection.

Based on the information in the OP, I would expect that the 13-Hz is a natural frequency of the structure. This can be confirmed by impact-response near top or motor (NDE) in two orthogonal directions in the horizontal plane. If this is confirmed, then then structure is excited by impacting in the pump from looseness created by excessive wear ring or shaft bushing clearances.

Walt

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