Electric motors have had a huge impact on the pump industry.
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Improved motor starters help Fabri-Kal achieve its green vision.
A paper or an electronic work order system can be used to capture alignment data.
An argument in favor of IEEE-841's provision for motor bearing protection.
In June, 2007, a reader asked Electrical Apparatus magazine, "How long should motor bearings last?" The answer will astound you:
"If (and it's a big if) ball bearings are kept clean and properly lubricated, their average or L-10 life should be 3 ½ centuries-3,180,000 hours."
Shaft failures do not happen everyday, but when they do, it can be a challenge to determine the cause of failure. Here's a technical explanation of what happens when the shaft bends or breaks.
Last month, we ended with a discussion of the relationship between peak and RMS (or effective) voltage. We found that the RMS voltage will always be 0.707 that of peak voltage, and peak voltage will always be 1.414 that of RMS voltage. This relationship holds true regardless of the sine wave frequency. But, as frequency changes, the total voltage applied to a circuit per cycle can differ substantially. To visualize this difference, we will need to introduce another unit of measure-volts per hertz.
It has been said that Washington, D.C., is the home of the largest invertebrate population in the U.S. This, of course, jokingly refers to the population of politicians and their lack of backbone or guts required to make difficult decisions. The same analogy could be applied to the single-phase motor, as it has only one-third the “guts” of its three-phase cousin. However, it can still perform well as long as expectations are reasonable.
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.
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.
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. I will provide a reference to a more in depth study at the end of this article.
Latest Motors Articles
Electric motors have had a huge impact on the pump industry.
Improved motor starters help Fabri-Kal achieve its green vision.
Facts can be tough—our emotions may get in the way. What we think we know is not always factual but is based on what we may intuitively feel is an undisputed truth. It is human to expect everyone else to agree with us, regardless if we truly know the facts or just think we do. And if others do not agree, then we think they are incompetent. Many people feel that all pump vibrations are bad, but is this a fact or only what we think is true?
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.
Most of us probably never notice the spinning cylinder mounted between the pump and motor, except how easy it is to dis/assemble when a pump or motor is changed out. Otherwise, the disc coupling never factors into our daily routine.
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.
It has been said that Washington, D.C., is the home of the largest invertebrate population in the U.S. This, of course, jokingly refers to the population of politicians and their lack of backbone or guts required to make difficult decisions. The same analogy could be applied to the single-phase motor, as it has only one-third the “guts” of its three-phase cousin. However, it can still perform well as long as expectations are reasonable.
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.
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.
Last month, we studied the properties and effects of resistive, inductive and capacitive loads in an AC circuit. This month, we will take self induction a step further and apply it to that very simple machine that is at the heart of AC power—the transformer.
Columns and Blogs
In this multi-part series, we will investigate several aspects of centrifugal pump efficiency.
First of Five Parts
Since the original publication of this draft standard in the January 2008 issue of Pumps & Systems, I have received feedback, encouragement, numerous questions and criticism. The draft listed three basic levels of repair.
The McGraw-Hill scientific dictionary [5] states that a volute is "a spiral casing for a centrifugal pump... designed so that speed will be converted to pressure."
