Is your company's electrical energy usage important to you? Whether still feeling the results of the recession or looking forward to competing as the global marketplace moves ahead, businesses are looking for ways to cut costs and increase revenues.
Trends in energy show utility companies raising rates and introducing more tiered rate structures that penalize high-energy consumers. And with all the talk about carbon footprints and cap and trade, energy becomes an important place to look for both savings and revenues.
So perhaps you've been formally tasked with improving energy efficiency for your company. Or maybe you've heard about the "Smart Grid" and are wondering how it will-or won't-impact your business. Perhaps you want to understand your corporate carbon footprint before regulatory pressures increase. Maybe you're a business owner or financial officer who needs to cut fixed costs. All of these and more are good reasons for finding out more about how you use electrical energy.
And you're not alone. A March 2009 article in the New York Times1 noted an increasing trend among large corporations to hire a Chief Sustainability Officer (CSO). SAP, DuPont, and Flowserve are just a few companies mentioned who already have CSOs. These C-level officers are usually responsible for saving energy, reducing carbon footprints, and developing "greener" products and processes.
While CSOs in large corporations may have a staff of engineers and a chunk of the marketing or production budget to help them find energy solutions, small and medium-sized industrial and commercial businesses usually take on this challenge as an additional job for their already overloaded technical or facilities staff.
This white paper takes a look at electrical power in the United States today, investigates the nature of the Smart Grid, and suggests ways that small and medium-sized companies can-without waiting for future technological development-gather energy data and control electrical energy costs today.
An Introduction to Data Loggers
"I just think the only way we are really going to get to the point we need to get to is to start collecting the real data."
This comment, made in 2009 by New York Public Service Commission chairman Garry Brown, conveys a growing sentiment about the need for solid, objective data on building energy performance.
When it comes to determining actual building performance, it all comes down to data. Data takes the guesswork out of energy management, and drives decisions as to what energy conservation measures need to be taken in a facility.
Portable data loggers are ideal tools for collecting building performance data. These affordable, compact devices can help establish energy performance baselines, and reveal a buildings performance under real-world, rather than modeled, circumstances.
They offer fine-tuned visual performance feedback, measuring changes in temperature and energy use when people enter and exit a building, turn on and off lights, or run heating and cooling systems. They can also be used to help ensure that indoor air quality and comfort are maintained in a building.
NFPA-79 is the electrical standard that has been developed by the National Fire Protection Association (NFPA) and is "intended to minimize the potential hazard of electrical shock and electrical fire hazards of industrial metalworking machine tools, woodworking machinery, plastics machinery and mass produced equipment, not portable by hand."
The National Fire Protection Association is also responsible for the National Electric Code (NEC)/ (NFPA-70).
The scope of NFPA-79 is summarized as follows: "The standard shall apply to the electrical/electronic equipment, apparatus, or systems of industrial machines operating from a nominal voltage of 600 volts or less, and commencing at the point of connection of the supply to the electrical equipment to the machine."
One of the focuses of the latest edition is to improve product safety by ensuring that appropriate types of wire and cable are used in the application with regard to current carrying capacity, temperature rating, or flammability.
As such, the guidelines for NFPA-79 compliant products are more stringent than those cables allowed by past editions.
The NFPA-79 provisions make specific reference to only two types of cable.
When it comes to accurately measuring the flow of liquid or gas, your flowmeter is only as accurate as the equipment it is calibrated on. And in the age of ISO 9001, ISO/IEC 17025, ANSI Z540 and other strict quality standards, this fact is becoming increasingly important.
Test and measurement applications depend on repeatable flow measurements, which provide performance criteria of the instrument being tested.
These devices often play a critical role on aircraft, placing greater demand on accurate flow test measurement for fuel consumption or hydraulic actuator controls.
Industrial operations live and die by the repeatability of process conditions. It is not enough for an individual flow-metering instrument to perform in a consistent manner, day in and day out; measurements must also be replicated. Multiple devices running on the same process-in different physical locations-must perform the same under identical conditions. This is only achieved through repeatable calibration equipment traceability to government metrology laboratories such as NIST.
For industrial operations, inaccurate flowmeter calibrations can have a serious impact on plant performance, ultimately resulting in poor yields or compromised quality. Therefore, periodic flowmeter calibration must be part of the user's quality process.
Mubeen Almoustafa, Calibration Application Engineer, Flow Dynamics. Inc.
Moore Industries believes it is of vital importance to have third-party SIS evaluation for plant safety provided by a company with global coverage and reputation. Earlier designs for process control and safety systems typically used "good engineering practices and experience" as their guidelines. As safety awareness evolved new standards started to evolve. International standards such as IEC 61508/61511 and U.S. born standards like ANSI/ISA84 require the use of more sophisticated guidelines for implementing safety. Unfortunately for manufacturers, compliance with IEC 61508 standards requires enormous documentation. In addition, more complex products require a greater depth of analysis. Software-based products such as those from Moore Industries are complex with their inherent programmable and flexible features unlike previous generation single function analog circuits.
Some companies are actively attempting to bypass the vital third party certification by proclaiming self certification to IEC 61508. This is not in the best interest of end users or the safety industry in general. Self certification is analogous as someone proclaiming compliance without third party testing on a hazardous area approval (such as Intrinsically-Safe).
Moore Industries has been working for many years with customers who require products for safety systems, including those compliant with worldwide safety standards such as ANSI/ISA 84 and IEC 61508/61511. To assist customers in determining if their instruments are appropriate for specific safety systems, Moore Industries has been providing Failure Modes, Effects and Diagnostic Analysis (FMEDA) reports for key products, and has been involved in the evolution of the IEC 61508 standard. As this standard has become more widely recognized and adopted by worldwide customers it was clear that end users were looking for products which had been designed to IEC 61508 from their initial concept. Customers are demanding not only compliance to the standards but verification from an independent third party agency such as TUVRheinland.
HIGH-SLIP BRAKING SOFTWARE PUTS THE BRAKES ON TRADITIONAL LOAD-BRAKING METHODS WITHOUT EXTERNAL EQUIPMENT
The techniques for braking of high inertial loads to a stop traditionally involved either Dynamic Braking or DC Injection Braking technology.
This article examines a new load-braking alternative called High-Slip Braking (HSB). We identify the different aspects of HSB, look at what it does, how it works, and how it is different from other braking methods. We also provide examples of "real world" successes, and discuss the new technology's cost effectiveness.
WHAT DOES HSB DO?
High-slip braking allows the stopping of larger inertial loads without the need for expensive and bulky braking options such as Dynamic Braking packages. Inertial loads involve only inertia and friction and given enough time, will tend to stop on their own when power is removed. HSB is most effective in applications involving infrequent stopping of inertial rotating loads where speed control during stopping is not required. Typical applications of this sort include; laundry equipment, centrifuges, large commercial fans, punch presses, blowers and mixers. Do not use HSB on overhauling static loads like; hoists, winches, elevators, product lifters, and similar applications. HSB is applicable only for complete stopping of the load and not as a means of braking for speed changes.
The HSB feature has proven to cut braking times in half without requiring extra equipment. The overall stopping time, however, does depend on the inertia of the load being stopped and the characteristics of the motor. HSB can achieve braking torque of more than 100% of the full motor torque.
Registration Evaluation Authorization and Restriction of Chemical Substances
It is certainly no secret to anyone that the past decade has placed a renewed focus on the environment and how all members of the world community, to include business organizations, affect it. Concerns about protecting the world in which we live have been the impetus behind such worldwide movements as recycling and renewable energy. From a manufacturing standpoint, RoHS (Reduction of Hazardous Substances) has impacted businesses as well as REACH, a more recent set of regulations that are becoming more significant to North American based manufacturing operations that are part of a supply chain that directly or indirectly supplies products into the European Union.
As with any new regulatory requirements, the initial exposure to the documentation can create a degree of uncertainty among those who will be asked to comply. From this perspective, REACH is no different from any of its predecessors. In an attempt to offer some understanding of the REACH regulations and some clarification of the requirements it places on manufacturers, C&M Corporation gathered Michael Karg, Director of Product Development, along with Randy Elliott, Regulatory Compliance Engineer, and Ariann Griffin, Regulatory Compliance Technician, to discuss some of the particulars of REACH and respond to some of the questions C&M has been discussing with members of its client base.
What is the purpose of REACH?
Mike Levesque, Randy Elliott, Ariann Griffin and Michael Karg, C&M Corporation
Some engineers think it is science. Others contend it is some type of black magic.
Many have no idea of exactly how the process works.
Regardless of what is known or unknown about the submission and evaluation process, there are few that will disagree with the premise that agency certifications, such as those offered by organizations like Underwriters Laboratories (UL), Canadian Standards Association (CSA), or Intertek, formerly known as Edison Testing Laboratories (ETL), to name only a few, are an important part of any product offering in the wire and cable industry. With todays focus on product safety, there has been an increased need for wire and cable products to carry either a listed or recognized mark signifying they have been independently evaluated and have met the appropriate safety guidelines that have been established based on their intended use.
In an attempt to help bring some clarity to the agency certification process for bulk cable, I have posed a series of related questions to Randy Elliott, C&M Corporations Regulatory Compliance Engineer. Randy has been a practicing engineer in the wire and cable industry for over 20 years. His background in R&D and design engineering has brought him into contact with regulatory agencies and their requirements on a regular basis throughout his career. For the past three years, his focus has been completely on regulatory issues for C&M.
Who is responsible for testing and what do their results mean?
This initiative is the first step in filling a noticeable void in industry - the lack of independent competency training in the Operations Management (MES/MOM) arena. This lack of wide-scale competency is recognized as a major barrier to plant and supply chain optimization and global operations excellence.
With members in 85 countries globally, MESA is an independent, objective community of like-minded people and enterprises working to make Operations more reliable, capable and profitable. Some of the foremost experts across the Operations Management landscape are leading the knowledge sharing within the MESA community by offering programs across 4 continents by mid-2011.
MESA Certificate of Competency (CoC) for MES/MOM* Methodologies: A 4-day, comprehensive program of MES/MOM Methodologies courses aimed at Systems Analysts, Architects, Programmers, Project Managers and Consultants.
MESA Certificate of Awareness (CoA) for MES/MOM Business Awareness: A 2-day, high-level program of MES/MOM Business Functions courses geared for executives, manufacturing/operations and IT personnel and sales professionals. The CoA courses are higher level, short versions of the CoC program.
Variable Frequency Drives (VFDs) with diode rectifier front end are typically equipped with a resistorcontactor arrangement to limit the inrush current into the dc bus capacitors, thereby providing a means for soft charging the dc bus capacitors. Because of the mechanical nature of the magnetic contactor typically used in VFDs, there exists a concern for fatigue. In addition, during a brown out condition, typically the contactor remains closed and when the voltage recovers, the ensuing transient is often large enough to possibly cause unfavorable influence to surrounding components in the VFD. Many researchers and application engineers have thought about this issue and many are actively seeking non-mechanical solutions in a cost effective manner.
In this paper, a new topology to soft charge the dc bus capacitor is proposed. Other techniques that have been evaluated are also introduced. The relative advantages and disadvantages are discussed. Experimental tests to show the feasibility of the proposed idea is also provided.
Mahesh Swamy, Tsuneo J. Kume and Noriyuki Takada, Yaskawa Electric America
Diode rectifier with large DC bus capacitors, used in the front ends of Variable Frequency Drives (VFDs), draw discontinuous current from the power system resulting in current distortion and hence voltage distortion. Typically, the power system can handle current distortion without showing signs of voltage distortion. However, when the majority of the load on a distribution feeder is made up of VFDs, current distortion becomes an important issue. Multi-pulse techniques to reduce input harmonics are popular because they do not interfere with the existing power system either from higher conducted EMI when active techniques are used or from possible resonance, when capacitor based filters are employed.
In this paper, a new 18-pulse topology is proposed that has two six-pulse rectifiers powered via a phase-shifting isolation transformer, while the third six-pulse rectifier is fed directly from the AC source via a matching-impedance. This idea relies on harmonic current cancellation strategy rather than the flux cancellation method and results in lower overall harmonics. It is also seen to be smaller in size and weight, and lower in cost compared to an isolation transformer. Experimental results are given to validate the concept.
Mahesh Swamy, Tsuneo J. Kume and Noriyuki Takada, Yaskawa Electric America
Events over the last several years have focused attention on certain types of loads on the electrical system that result in power quality problems for the user and utility alike. Equipment which has become common place in most facilities including computer power supplies, solid state lighting ballast, adjustable speed drives (ASDs), and un-interruptible power supplies (UPSs) are examples of non-linear loads. Adjustable speed drives are also known as Variable Frequency Drives (VFDs) and are used extensively in the HVAC systems and in numerous industrial applications to control the speed and torque of electric motors. The number of VFDs and their power rating has increased significantly in the past decade. Hence, their contribution to the total electrical load of a power system is significant and cannot be neglected.
Non-linear loads are loads in which the current waveform does not have a linear relationship with the voltage waveform. In other words, if the input voltage to the load is sinusoidal and the current is non-sinusoidal then such loads will be classified as non-linear loads because of the non-linear relationship between voltage and current. Non-linear loads generate voltage and current harmonics, which can have adverse effects on equipment that are used to deliver electrical energy. Examples of power delivery equipment include power system transformers, feeders, circuit breakers, etc. Power delivery equipment is subject to higher heating losses due to harmonic currents consumed by non-linear loads. Harmonics can have a detrimental effect on emergency or standby power generators, telephones and other sensitive electrical equipment.
When reactive power compensation in the form of passive power factor improving capacitors are used with non-linear loads, resonance conditions can occur that may result in even higher levels of harmonic voltage and current distortion thereby causing equipment failure, disruption of power service, and fire hazards in extreme conditions.
The electrical environment has absorbed most of these problems in the past. However, the problem has now reached a magnitude where Europe, the US, and other countries have proposed standards to engineer systems responsibly, considering the electrical environment. IEEE 519-1992 and EN61000-3-2 have evolved to become a common requirement cited when specifying equipment on newly engineered projects. Various harmonic filtering techniques have been developed to meet these specifications. The present IEEE 519-1992 document establishes acceptable levels of harmonics (voltage and current) that can be introduced into the incoming feeders by commercial and industrial users. Where there may have been little cooperation previously from manufacturers to meet such specifications, the adoption of IEEE 519-1992 and other similar world standards now attract the attention of everyone.
One of the main driving force behind the industrial revolution was the invention of the electric motor more than a century ago. Its widespread use for all kinds of mechanical motion has made life simple and has ultimately aided the advancement of human kind. The advent of the inverter that facilitated speed and torque control of AC motors has propelled the use of electric motor to new realms that was inconceivable just a mere 30 years ago. Advances in power semiconductors along with digital controls have enabled realization of motor drives that are robust and can control position and speed to a high degree of precision. Use of AC motor drives has also resulted in energy savings and improved system efficiency.
Yaskawa Electric Corporation has been at the forefront of technology, creating reliable drives that consistently push the envelope of engineering achievement. This paper reviews Yaskawa's role in the development and application of the inverter technology to AC motor drives and introduces some futuristic vision for the motor drive technology. The development of more efficient, more powerful electric motor drives to power the demands of the future is important for achieving energy savings, environmentally harmonious drives that do not pollute the electrical power system, and improving productivity. Yaskawa wants to be an integral part of this future and hopes to contribute significantly to achieve this.
Mahesh M. Swamy and Tsuneo Kume, Yaskawa Electric America
Differential pressure transmitters were first implemented in the 1950s but are still one of the most commonly used technologies for measuring liquid level in process industries. In many areas of the industrial level measurement market - including chemical, petrochemical, refining, and electric power generation—differential pressure transmitters have captured the vast majority of level applications; and still represent the largest worldwide sales volume of process level measurement equipment. Their popularity and installed base is so prevalent because DP transmitters are versatile, cost-effective, and due to their long history, plant personnel are familiar with their operation.
1. Power consumption by electric motors
Worldwide, about two-thirds of the electricity is consumed by motors used in powers industrial facilities. According to DOE report, the motor systems are responsible for 63% of all electricity consumed by U.S. industry and electric bill represents more than 97% of total motor operating costs.
Rapidly increasing energy cost and strong global interest in reducing carbon dioxide emissions are encouraging industry to pay more attention to high-efficiency motors.
Permanent Magnet (PM) motors have higher efficiency than induction motors because there are no I2R losses of the rotor. But widespread use of the PM motors has been discouraged by price and requirement of a speed encoder.
Recent release of low-cost high-performance CPUs and establishment of the speed sensorless control theory (hereinafter referred to as an open-loop vector control method) enables the advent of a general-purpose open-loop control PM drive. In this white paper, the open-loop PM motor control technology is introduced and its characteristics and major application fields are described.
Predicting and managing control valve noise has long been an important consideration in gas and steam applications, with the dual goals of protecting workers from potential auditory damage and preventing excessive vibration that could destroy equipment and piping, possibly leading to a catastrophic failure.
At first glance, it may seem that a logical way to achieve these goals would be to limit valve trim exit velocity head to a maximum of 480 kilopascals (kPa), and this indeed is how some have addressed the issue. In practical application, however, it is an oversimplified approach that, in many cases, will not produce the desired results. First, it typically requires the use of expensive multi-stage or multi-turn trim designs, which can cost up to 30 percent more than a simpler solution. More importantly, it also can create a false sense of safety.
This article will explain why the focus should instead be on keeping the valve outlet Mach number low. Practical examples will be used to illustrate that:
- Even if the trim exit velocity head is kept below 480 kPa, valve noise can be unacceptably high if the valve outlet Mach number is high.
- Even if the trim exit velocity number is above 480 kPa, valve noise can be kept to acceptable levels - without using costly trim designs - if the valve outlet Mach number is kept low.
The manner in which a measured process variable responds over time to changes in the controller output signal is fundamental to the design and tuning of a PID controller. The best way to learn about the dynamic behavior of a process is to perform experiments, commonly referred to as "bump tests." Critical to success is that the process data generated by the bump test be descriptive of actual process behavior. Discussed are the qualities required for "good" dynamic data and methods for modeling the dynamic data for controller design. Parameters from the dynamic model are not only used in correlations to compute tuning values, but also provide insight into controller design parameters such as loop sample time and whether dead time presents a performance challenge. It is becoming increasingly common for dynamic studies to be performed with the controller in automatic (closed loop). For closed loop studies, the dynamic data is generated by bumping the set point. The method for using closed loop data is illustrated. Concepts in this work are illustrated using a level control simulation.
Jeffrey Arbogast, Department of Chemical Engineering University of Connecticut; Douglas J. Cooper, PhD, Control Station, Inc.; & Robert C. Rice, PhD, Control Station, Inc.
Manufacturing and production processes have had to be controlled and managed in real time from inception because they change in real time frames. This has been a natural premise of industrial systems from the very beginning.
A major shift in the business of manufacturing has occurred over the past decade which is driving the dynamics of the business of production and manufacturing into the real time domain. Business variables, such as energy prices, feedstock prices and even product prices have rapidly transitioned from highly transactional time frames into real time frames. For example, a decade ago it was not unusual for an industrial plant to establish a contract with its energy supplier that essentially set the price over an extended time period, of often 6 months or even a year. Today, in most parts of the world, long term fixed price energy contracts are not being offered and the price of energy can change multiple times in a day. The implications of this transition are clear. Industrial business functions must operate in real time to be effective and efficient. Industrial companies that do not move to real time business operations will be at a severe disadvantage in their marketplace.
Invensys, Peter G. MartinInvensys, Peter G. Martin
Many industrial businesses and manufacturing operations were designed, implemented and operated around a set of basic assumptions that have served the industry well over the last century. For example, although it was expected that the values of process variables, such as flow, level, temperature and pressure, would naturally fluctuate in real time, business variables, such as production value, energy cost, and material cost were assumed to be fairly stable over long periods of time. It was also typically assumed that the production operations could effectively work independently from the business operations. Production operations would focus on making the products while business operations would focus on reporting results. This, in turn, led to a bottom-up business information flow perspective. Business information was used only for reporting results and only the required data from the operation had to be provided to the business reporting system. Often no business information flowed to the operations.
The traditional focus of industrial operations resulting from these assumptions has been on operational objectives, such as throughput and consumption of resources, as compared to business objectives. Typically, plants were designed to maximize production output, which proved to have the limited agility necessary to meet market demands during economic downturns.
Finally, the labor mindset of the industry resulting from the workforce dynamics of the early industrial revolution is, for the most part, still very much part of the standard operational philosophy utilized in today's industry. A huge separation continues to exist between the professional and management staffs from the operations and maintenance staffs that comprise today's labor force. This separation was necessary during the formative period of the industrial revolution when the available labor force was unskilled and almost completely uneducated. Although today's "labor force" is fairly well educated and highly skilled in comparison, the professional and management teams still tend to work under the traditional assumptions. For example, the operator interfaces of most industrial automation systems have been designed around a philosophy called operations by exception. Essentially this means that operators are to do nothing that impacts the plant unless an exception condition, an alarm or event occurs that requires human intervention. Once the event is addressed, operators can go back to doing nothing. This philosophy was developed to protect the plant from the uneducated and unskilled operators.
For the most part, these traditional industrial assumptions have served the industry quite well up to this point. However, there are current changes underway that are beginning to show that these traditional assumptions will not be effective going forward.