Bearings

Latest Bearings Articles

Bearing currents occur in specific motor and drive installations and can lead to motor fatigue and failure. While no system is inherently immune to bearing currents, few installations experience bearing currents during normal operation. While many installations have preventive measures installed, knowing that protection is in place is sometimes outside the owner or operator’s scope.

Misalignment is a frequent cause of rolling bearing failure. It can cause cage fracture, which will result in seizure of the bearing, pump failure and costly downtime. It can also cause edge loading, which will result in early bearing failure.

Bearings in centrifugal pumps support hydraulic loads imposed on the impeller, the mass of the impeller and shaft, and loads caused by couplings and drive systems. They also keep axial and radial shaft deflections within acceptable limits for the impeller and shaft seal.

With more than 20 years of experience in the oil and gas industry, Lukoil, a Russian oil and gas business, aspired to expand its oil and gas fields. For the expansion, Lukoil selected the Bolshekhetskaya depression in West Siberia, where large deposits of ceromanian gas lay.

When pumping river or well water, abrasive particles—such as sand and other debris—erode hardware quickly. This leads to poor performance and costly, frequent repairs.

When a representative from a local distributor noticed a large amount of oil leaking from a semi-autogenous grinding (SAG) mill gearbox at a copper mill, he decided that a permanent solution to the maintenance issues caused by inefficient sealing methods was needed.

Industrial equipment users are often confronted with pump parts issues. Handling these issues requires making experience-based decisions and prioritizing. How pump hydraulic and wear components in existing inventory are treated is an issue that merits consideration.

When designing an application, the design engineer must consider proper bearing lubrication. The lubrication method affects the proper operation of the equipment and the cost of maintaining it. Once the lubrication method is determined, selection of the proper lubricant oil viscosity is vital for prolonging the life of the equipment’s rolling element bearings.

A Kansas City motor repair shop developed a virtually foolproof process for protecting pump motors from electrical bearing damage caused by stray shaft currents. For six years, Scott Wilkins, the manager of motor shop operations, has overseen the reconditioning of hundreds of vertical motors through a process known as the vertical motor solution. None of them has had repeat bearing failure.

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Columns

In my June column on pump and motor testing, I said that three-phase voltage variation and unbalance can have a significant effect on motor insulation life. Voltage variation is defined as the difference between the motor nameplate voltage and the incoming source voltage.

One of the supposed advantages of centrifugal pumps when compared to positive displacement pumps is their ability to operate across a wide flow range.

A reciprocating power pump, as depicted in Figure 1, is a displacement machine. It has characteristics that are different than a centrifugal pump.

Blogs

The global water crisis claims 5,500 lives each day—more than war, natural disasters, AIDS or hunger. It is a sobering problem but not an impossible one to solve.

SKF hosted their annual Technical Press Day on June 9, 2014, at Penske Headquarters in Mooresville, North Carolina. This was my first event to cover for Pumps & Systems, so I had a lot to learn! Here are a just a few of the things I picked up at press day.

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