Water and wastewater systems in the United States use a tremendous amount of power. The EPA estimates that these systems use 50 trillion watt-hours annually at a cost of $4 billion. Combined with electric rate increases upward of 20 percent in a single year, water and wastewater system operators are left with an enormous strain on their budget.

Following the development of variable frequency converter drives during the 1990s, totally enclosed fan-cooled (TEFC) AC induction motors became viable options for replacing DC motors in pumping applications. The torque and speed characteristics of these motors are a close match to those required for centrifugal pumps.

Aligning an electric motor coupled to a large air blower required multiple measurements.

Following the development of variable frequency converter drives during the 1990s, totally enclosed fan-cooled (TEFC) AC induction motors became viable options for replacing DC motors in pumping applications.

It has been said that Washington, D.C., is the home of the largest invertebrate population in the U.S.

A paper or an electronic work order system can be used to capture alignment data.

The frame sizes (physical dimensions) of AC motors have changed substantially through the years. Originally, they were considerably larger than those in use today. This increased size was the result of inefficiency and the need to dissipate heat.

Last September, we spoke about the importance of pipe-to-piping alignment, evaluating actual numbers, and tabulating stress values as they approach yield stress of pipe at various values of misalignment. This time, we will discuss the effects of pump-to-motor misalignment, beyond hype or generalities, by numerically quantifying the conclusions.

Last month, we ended with a discussion of the relationship between peak and RMS (or effective) voltage.

Couplings are often forgotten until a project is nearing its end.

A large wastewater processing plant experienced continual problems with its influent raw wastewater pumps for several years.

Couplings are often forgotten until a project is nearing its end.

Back in the early seventies, when I was in grad school, our government pledged to convert the U.S. measurement system to the metric system. A popular cartoon at the time showed a lab technician with a box of amputated human feet standing at the door of the supply room. The supply clerk was also holding a box, but his was full of volt meters. The caption was "Trading Feet for Meters." That was almost 37 years ago, and we still have most of those feet! I guess that I could say that we are still "inching" into the metric system.

Advanced motor protective relays provide superior protection for motors and pumps. pump system optimization

A flexible coupling's primary functions are connecting two shafts, transmitting power from a driver shaft to a driven shaft and accommodating the misalignment between them.

The SI system is the modern day version of the metric system, and the U.S. gets a lot of grief for not embracing its inherent transportability across international boundaries.

Owing partly to tradition, the shafts of electric motors are often larger than those of the equipment they drive.

Last September, we spoke about the importance of pipe-to-piping alignment, evaluating actual numbers, and tabulating stress values as they approach yield stress of pipe at various values of misalignment. This time, we will discuss the effects of pump-to-motor misalignment, beyond hype or generalities, by numerically quantifying the conclusions.

The industrial motor world has a new specification available for defining the requirements of general purpose, severe duty motors in the 250- to 3,000-hp range.

Proper alignment of the pump shaft with the driver can reduce vibration and significantly improve reliability.

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