Why and how do leading OEMs choose a variable speed motor for their equipment?

I received many comments on my four-part series on AC Power, and most of them were very positive.

Water and wastewater systems in the United States use a tremendous amount of power.

In the past year, the rate of acceleration in the cost of raw materials (including steel, iron ore, copper and aluminum) has reached unprecedented levels in the pump and rotating equipment industries.

When maintaining motors, proactive strategies are required.

The economic downturn has delivered a heavy blow to the industrial manufacturing sector in North America. Manufacturers are indicating sales drops of 30 percent to nearly 60 percent compared to that of 2008.

This month we will quickly look at the load types that comprise a typical AC circuit.

All electric motors (motors) have a housing that contains the working components of the motor.

With highly reliable electrical systems, protective relays may be called upon to operate very infrequently.

The Energy Independence and Security Act of 2007 (EISA), which restates and broadens the definition of General Purpose Electric Motors, goes into effect on December 19, 2010.

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.

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