Latest Motors Articles

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

The U.S. has not enacted a wide-reaching, industrial energy efficiency bill since 1992 when the Energy Efficiency Policy Act was passed.

The RPMAC PM Direct Drive Cooling Tower Motor and VS1CTD Drive for wet cooling towers replaces an existing motor, jack shaft and gearbox with a more efficient and environmentally responsible variable speed motor and drive with the motor mounted directly under the fan.

Most of the electric motor information we use on a daily basis is pretty straightforward.

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.

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.

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

As a follow up on my AC Motors series, I thought it would be a good idea to provide a short overview of work, power and torque as it applies to the AC motor.

A number of choices are available when connecting pumps, fans and other rotating equipment to an electric motor. There are numerous mechanical and fluid coupling designs and, in some cases, a belt drive option is available.

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.

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.

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

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

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.

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.

Energy is the largest ongoing cost of mixer operation, so it is vital to carefully consider the energy-to-thrust ratio (sometimes called the “water-to-wire” ratio) for each and every mixer application.

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