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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Soft foot is one of the most prevalent conditions found in rotating machinery. This condition, if not corrected, makes an alignment job much more difficult and sometimes impossible. If the internal alignment is not correct, the external alignment will not matter.
SCADA can be utilized for remote data acquisition, but because it is primarily a real-time control system, the user must make significant compromises to use it for this purpose. These compromises include cost, data integrity, flexibility, convenience and control of the task. Here are some considerations to think through.
Last month, we discussed thermal radiation and material properties and the thermal nature of materials. We also looked at the emissivity of real objects using a stainless steel block. This month, we will discuss other characteristics demonstrated by the steel block example.
Mechanical pressure gauges, which require no external power, provide an affordable and reliable source of accurate pressure measurement. Using the criteria below can help maximize gauge life.
To explain why the apparent temperature seen through a thermal imager can be significantly different than the actual temperature, we will review our knowledge of physics.
Potential to Failure (P-F) curves graphically display the failure time cycle and measurement techniques that can be used to detect asset failures prior to reaching the asset incurring functional failure. Proactive strategies should focus on managing assets high on the P-F curve, or early (P1 to P5) in the failure cycle (Figure 1). The ability to detect failures early in development allows top quartile performers to proactively manage their maintenance programs by understanding the health of their assets. Many companies, however, find it difficult to operate proactively and continually react to assets that reach functional failure with little or no warning.
As pump users, we often have to deal with fuzzy concepts, such as: What is low flow? When are vibration levels too high? When is suction specific speed value too high? When is a pump's energy level high?
Water chemical compatibility and electrical interference are two major challenges for control systems. Two major sources of fresh water can limit the performance of the control system.
State and federal requirements increase the need for pump monitoring and control.
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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."
