Off-BEP Energy Cost
Keeping a close eye on pump efficiency can lead to energy savings.Last month, I discussed the Draw Down calculator and its role in determining the actual operating point of wastewater pumps. Like...
In my opinion, the system curve is the single most important component of the pump selection process. After all, the system curve determines the operating point on a pump’s performance curve. Other...
Rotary pumps are positive displacement pumps that use rotational, rather than reciprocating, motion during their pumping cycle. They can be designed to pump liquids, solids, gases or mixtures of all...
My September tutorial took a look at the affinity laws and showed why each is able to predict changes in flow, head, and power when there is a change in pump speed or impeller diameter.One thing I did...
In the February 2010 issue of Pumps & Systems, I discussed my Suction Specific Speed (S) Calculator and its ability to predict the stable range of flow for a particular centrifugal pump. In November...
The Bernoulli Principle
Read Part OneRead History of Pumps seriesThe Bernoulli Principle explains the flow of fluids and was one of the earliest examples of conservation of energy. It states that during steady flow, the...
Today’s federal requirements dictate the minimum efficiency of an electric motor, but they do not have any impact on the efficiency of a centrifugal pump. A 10-horsepower, 1,800-rpm motor must meet...
Memorization and learning are two different things. As I look back on my own education—formal and real life—most of the facts and figures that I memorized are long gone. Even today, routine...
The Life and Work of Daniel Bernoulli
Editor's Note: This is the first article in a two-part series on Daniel Bernoulli. The series is part of a larger ongoing series on the history of pumps.Have you ever noticed that the pressure...
This article is part of our ongoing series on the history of pumps. In 2008, I wrote a two-part article on waterhammer and how it can damage pumps and piping systems. It is the result of a change...
Three Fictitious Forces & One Real Force
Pumps & Systems, April 2013Two schools of thought exist with regard to centrifugal force. The one I support views it as a false force. The other side believes that it is real. That is the side...
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...
In my July 2014 column, I demonstrated that three-phase voltage variation can significantly affect several alternating current (AC) motor characteristics. If that variation is large, it can also...
"Testing Centrifugal Pumps in the Field,” Pumps & Systems, February 2011, featured an Excel spreadsheet designed to simplify the field test procedure. The equation for total dynamic head (TDH)...
Variable Frequency Parallel Pump Analyzer
There are several ways to control two identical, parallel pumps operating under variable frequency control in pumping applications. One method is to size a single drive to handle both pumps and vary...
Variable Speed Pump Analysis
When selecting a pump for variable speed operation, a number of conditions must be evaluated. For example, will the performance curve allow the range of operation required by the application? Will the...
Wastewater Pump Draw Down Calculator
Based on several of my previous Pumps & Systems articles, you probably know that I have major concerns about the off best efficiency point (BEP) operation of wastewater pumps. Last month, I...
Why Wye? Why Delta?
Last of Three Parts
Why Wye? Why Delta?
Pumps & Systems, July 2013Second of Three PartsThe secondary configurations reviewed in Part One (Pumps & Systems, June 2013) are typical three-phase configurations found in pump applications....
Why Wye? Why Delta?
First of Three PartsOne of the more confusing elements of three-phase power is the winding connection schemes for inductive devices such as transformers and motors. Although most of us with a basic...