This article will define a business case for achieving significant rotating equipment maintenance and energy cost reduction at industrial and municipal facilities.
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The second part of this three-part series explores the types of protection applied to specific equipment installed at water and wastewater facilities and some typical criteria used to develop protective settings.
Last month, we ended our discussion of proportional control by saying there are times when P alone cannot provide the accuracy required by a process. Take, for example, a constant pressure booster system under VFD control. If changes in flow and the resulting change in pressure occurred gradually over a long period of time, the VFD could use proportional control to keep pressure constant.
Wireless control and monitoring are a vital part of pump systems.
Today's lean maintenance staff needs pump and motor protective devices that diagnose and predict problems before they become acute.
Paddle wheel flow sensors not only continue to remain strong in industrial applications, their use is growing. Because these devices offer the lowest cost per sensing point of any flow measurement technology, users can save significantly on purchase, installation and maintenance costs.
A successful infrared program involves planning and action. This article outlines steps that will help you implement a thermography program.
Interpretation of equipment clues can help diagnose problems before failure occurs
Last year in “Trending Revelations in Vibration Analysis,” (Pumps & Systems, June 2009), I discussed the importance of statistic trending in vibrations analysis. Usually, as most would expect, vibrations gradually increase with time. This increase reflects the normal internal wear, accumulative misalignment and deformations that can occur within a pump. All these wear conditions will lead to eventual failure.
A Nashville-based hunting club required the flooding of several acres of land. A shallow area approximately 1.5-ft deep needed to be flooded to help attract wild game.
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This article will define a business case for achieving significant rotating equipment maintenance and energy cost reduction at industrial and municipal facilities.
The Merchandise Mart in Chicago, Ill. is the world's largest commercial building, largest wholesale design center and a premier international business location. Encompassing 4.2 million gross square feet, the Mart spans two city blocks and stands 25 stories high. It welcomes more than three million visitors each year to its retail shops; boutiques; 11 floors of permanent showrooms for gift, residential, casual and contract furnishings; 10 floors of office space; dozens of trade shows and a myriad of special educational, community and consumer events.
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 frequency range be large enough to allow stable operation? What is the hydraulic efficiency from minimum to maximum flow? What level of power savings can be expected? These are some of the important questions that arise during the pump selection process and there are several others.
Over the past 50 years, advances in technology have provided the primary thrust behind the success and evolution of variable-speed drive systems. Here are some considerations for the proper selection and set up of different types of systems, and what lies ahead in the future.
Water system operators know the challenges of keeping municipal drinking water consistently and safely chlorinated. Increased safety concerns regarding common disinfectants and mandated chlorine residual targets make maintaining large or small water systems difficult.
Industry analysts predict that in the near future, most motors will be controlled by variable frequency drives. Here are the reasons why.
PWM inverters introduce motor shaft voltages and bearing currents. The bearing damage in inverter-driven motors is mainly caused by the shaft voltage and bearing currents created by the common-mode voltage and its sharp edges [1]. All inverters generate common-mode voltages relative to the power source ground that cause coupling currents through the parasitic capacitances inside the motor. The main source of bearing currents is the capacitance-coupling currents that return via the motor bearings back to the ground.
Economic pressures to minimize production downtime and improve operating efficiency are increasing the emphasis to accomplish on-site problem detection, analysis, and resolution as fast as possible. These requirements place a great deal of pressure on maintenance personnel to have all the right tools readily available in one place.
Most VFD systems use some form of closed-loop feedback to avoid surging, excessive noise, and in extreme cases, vibration. A reliable encoder signal is one method that minimizes speed variance and helps eliminate these unwanted effects. Here's how it works.
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."
