Pumps having hot roller bearing

[Banting]

I am working on a new 45kW centrifugal water pump, which is >70C at the roller bearing pedestal. I wonder what' s causing such high temperature.

The vibration measured at the bearing pedestal is indeed very small. The pump seems to be well balanced and lubricated.

 

[dr dodge]

if there is no real vibration, the bearing endplay/pre-load would be where I looked next. unless some "lands" around the bearing are causing the rubbing of other surfaces (bearing bore too deep, etc)

dr

 

[FredGarvin]

Let's get some more info on this one data point:

- Is this a new installation?
- Have you verified your instrumentation?
- pump speed =?
- # of balls in the suspect bearing = ?
- what kind of load, i.e. flow and pressure?
- Any other operational info
- Has the pump been recently serviced?
- Are you sure the bearing is cooled properly?

Usually an overtemp with low vibs is a sign of either too little or too much lubrication. In the case of too much, the scavenge of the cooling flow in insufficient to get the fluid away from the bearing so it just keeps heat soaking the bearing. It is especially important to look at recent maintenance and any other things that could have been done to the pump, i.e. its history.

 

[Banting]

Some additonal informations

- Is this a new installation?
Yes, both the pump and motors are new
- Have you verified your instrumentation?
The sensors were calibrated just before the measurement
- pump speed =?
740rpm
- # of balls in the suspect bearing = ?
Roller bearing, 14 rollers dia 25.7mm, bearing pitch dia 132.5mm
- what kind of load, i.e. flow and pressure?
- Any other operational info
Design flowrate is 0.35m^3/s, pressure head is 8m
- Has the pump been recently serviced?
I don't know exactly how long the pump is in service, i think it s about a week or two
- Are you sure the bearing is cooled properly?
I don't know the amount of lubricants. We would check with the pump operator if it is the suspicuous cause

 

[FredGarvin]

Because this is a new installation, did anyone verify alignment when it was installed?