AC Articles and Application Notes

Analysis and Evaluation of Switching Power Supplies

        Observing circuit-internal waveforms, checking operating status, and confirming

LXI Simplifies Satellite Testing System

The group’s goals are to develop, support and promote the LXI standard. LXI’s flexible packaging, high-speed I/O, and prolific use of LAN address a broad range of commercial, industrial, aerospace and military applications.

AC Ballast Testing

Ballast manufacturers faced with demands for increased throughput and greater reliability are now looking to Elgar for programmable AC power sources to help solve their automated test problems.

Automotive Application Information

Application note discussing SmartWave's powerful waveform creation for Automotive Power Bus Disturbance simulation testing.

DO160D AC Power Tests

Application note discussing Elgar's SmartWave compliance with the June 2001 RTCA DO160D Section 16.

Global UPS Tackles Harsh Demands

EE Times article reviewing considerations in evaluating ruggedized UPS's.

How to Select an AC Power Source

Article discussing the steps to walk you through the process of sizing an AC power source.

Oil Logging

Application profile on basic principles of oil logging.

DC Articles and Application Notes

Choosing a Power Supply for Automotive Electronics Testing

Evaluation Engineering article reviewing pros and cons of various DC supply topologies.

DC Margin Testing

Application note discussing use of programmable DC supplies in margin testing.

Articles - Harmonics

Plain as the Nose on Your Face

When searching for the source of harmonic pollution, one of the most obvious sources of such should not be overlooked: fluorescent lighting fixtures.

Articles - Power

The Inefficiency of PQ

Statistics about the financial impacts of power quality phenomena on productivity.

Paper Tools

There are many different types of tools available for troubleshooting, auditing, and evaluating that power quality compatibility and susceptibility of a facility.

Pro-Active vs. Re-Active

As with other aspects of business, there are people and companies that operate in the pro-active mode and those that at in the re-active mode.

Articles - Flicker

With a Flick of My Bic

Flickering of the lights in an office, factory, or residential home isn't a new power quality phenomena, but is one that is receiving more attention lately.

Finding the Source of Flickering Lights

Flicker is the perceived change in light output from a lamp, caused by the fluctuation of the supply voltage at an office, factory, or residential home.

Harmonics

Active Filter Design and Specification for Control of Harmonics

Active filters have become a viable alternative for controlling harmonic levels in industrial and commercial facilities.

Power Factor Correction and Harmonic Controls for dc Drive Loads

The design of power factor correction and harmonic control equipment for loads at a plastic film manufacturing plant.

It Isn't Easy Being Green

By 2000, 65% of the load will be non-linear.  The result is an increase incurrent harmonics, which in turn results in the propagation of harmonic-based voltage distortion.

Harmonics: Understanding the Facts

Understanding what is important to know about harmonics can be challenging for those without extensive electrical engineering backgrounds.

Harmonics: Understanding the Facts, Part 1

In this three part series, the first article will review what a harmonic is.

Harmonics: Understanding the Facts, Part 2

In this three part series, the second article will help to clarify what those important facts are.

Harmonics: Understanding the Facts, Part 3

In this three part series, the third article will provide details on what causes harmonic problems and suggested solutions.

Tec Tip on Harmonic Power Flow Direction

Most people in the power engineering field have encountered the question about which direction the harmonic power is flowing, from the source to the load, or from the load to the source.

General

The Need for Speed

Information is power, but its power is diminished if it doesn't arrive at the location(s) where it is needed when it is needed.

The Sign of the Sine

The sine wave is one of those signs that the universe wasn't just randomly put together.

Developing a Utility/Customer Partnership

Determining the optimum supply systems and customer electric system characteristics for sensitive customers requires a careful evaluation of different alternatives.

Monitoring

Utilization of Web-based Power Quality Monitoring

Power quality monitoring is an essential service many utilities perform for their industrial and larger commercial customers.  Because of the technology and software now available, this monitoring is a highly effective tool.

A Systems Approach to Power Quality Monitoring

In the dawn of deregulation, power providers and consumers are changing their view of systems performance.  This evolution is being driven due to the increasing awareness of power quality's role in customer systems.

Case Studies - High Reliability

7 x 24 Customer Service Center

In 2000, DHL Airways opened a new 24x7 customer service center to support is US customer base.

Bank's High 9s Infrastructure Saved from Disaster

The power system for this major NYC bank providing nationwide credit card and other financial transactions appeared to be performing satisfactorily.

Hospital's Power Outage Problem Solved

A lightning storm caused a fault that resulted in the operation of a re-closure of the utility feed to this large city hospital.

Major Health Care Center

Severe power quality problems damaged X-ray equipment, costing $100,000 in one instance.

Utility Power Factor Capacitor Bank Switch Problem

CT Scan system was experiencing repeated computer lockups and component failures.

Case Studies - Manufacturing

Manufacturing Process Unexpectedly Halted

This medium-sized manufacturing facility, located in an industrial park that experienced an unexplained shutdown of several adjustable speed drivers (ASDs), wreaking havoc on key process equipment.

Textile Industry Evaluation

Despite their differences, continuous-process industries share underlying characteristics: they maintain continuous operations in facilities that represent substantial start-up costs and time, but can be interrupted or disrupted by seemingly minor fluctuations in power quality.

Harmonics Generated from the Source

The subject company manufactures meat products such as sausage, salami, and bologna.  Most of their load consists of HVAC and refrigeration as they have about 6000 sq. feet of cold room storage.  They also have machinery such as grinders, slicers, and presses.

Voltage Transients Causing Diode Failures

A plastic extrusion manufacturer in the Midwest had a 480V delta feeding a plastic extrusion machine.  The ASD-driven synchronous motor in the extruder had a half-wage bridge rectifier circuit to provide excitation voltage to the pole coils

Articles - General

Approaching with Tools

Both the "approach" and the "tools" are very important for carrying out an efficient, productive and safe monitoring program.

The Big Event

The key issues here are system operation and system susceptibility.

The Crystal Ball of Power Quality

As we enter what some say is the real start of the new millennium, the future of power quality monitoring is based on what can be seen at trade shows, conferences, and web sites.

There's Gold in Those Waveforms

As the IEEE Standard 1100-1992 points out, the more efficient power supplies "can be both a contributor to and a victim of powering and grounding incompatibilities in the power system."

The Power Industry Gets a Little Older

As the infamous Y2K approaches, power quality monitoring equipment is entering the fifth generation of products.

The Right Medicine

There are a whole plethora of solutions on the market for power quality related problems.  Choosing which one is the best for a particular facility and its problems is similar to a doctor prescribing the right medicine for a certain illness.

Don't Overlook the Obvious

Checking for the obvious first can often lead to a more cost-effective solution more quickly than just dragging out the power quality analyzer and begin collecting data.

An Ounce of Prevention

The old adage about "an ounce of prevention is worth a pound of cure" is applicable to the power quality world.

Be Prepared

Being prepared includes knowing what the present quality of the electrical supply provided by your current provider is as well as the susceptibilities of the equipment in your facility.

Waves

The rise and fall of ocean waves is like the sine wave of the ac voltage waveform that is often used as the basis to compare with as a means to determine the quality of the supply.

M-I-C-K-E-Wye

When setting out to monitor three phase power systems, one of the first factors (after safety, of course) is to determine if the circuit is a wye or delta configuration.

Wye, Too (not to be confused with Y2K)

Take a look at the effect of the monitored values, depending on what side of the transformer you are connected to, as well as some other effects from different configurations.

Distributed Generation

Return of DISCO

Deregulation has sparked the break-up of the traditional organizational structure of inventor-owned electric utilities into generators, transcos, and discos.

Power Quality - A Critical Element for Distributed Generation

The increase in electricity generation capacity has not been keeping up with the growing steady state and escalating peak demand in many parts of the world.

Power Quality

Power Quality Contracts in a Restructured Competitive Industry

Who will be responsible for the quality of power being delivered in the deregulated utility industry?

Detecting, Identifying, and Correcting Power Quality Problems

Disturbance waveshapes from power quality monitors provide important clues toward locating the source of problems.

Interpretation and Analysis of Power Quality Measurements

Advanced in power quality monitoring equipment and software tools for analyzing power quality measurement results.

Effects of Voltage Sags in Process Industry Applications

Causes of voltage sags in affecting process industries, their impacts on equipment operation, and possible solutions.

Economics of Different Plant Ride-Through Improvement Solutions

Determining the optimum supply system and customer electric systems characteristics for sensitive customers requires and economic evaluation of different alternatives.

Advances in Data Reduction Techniques

The quantity and quality of the data being captured in current power quality monitors has been increasing significantly in recent years.

Power Quality Starts at the Load

Recent work being done on the power supply performance and load susceptibility.

Sags and Swells

Sags and swells are the most common types of power quality disturbances.

Simple Rules for Solving Power Quality Mysteries

A typical power quality problems requires a power quality monitor capable of reliably capturing the necessary information.

Another Tool for the Toolbox

IEEE Standard 1346 Electrical Power System Compatibility with Electronic Process Equipment.

Grounding

Principles of Grounding

Fall of potential - 3-point measurement

Understanding Ground Resistance Testing & Soil Resistivity

Why measure soil resistivity, Effects of soil resistivity on ground electrode resistant, and factor affecting soil resistivity.

Clamp-On Ground Resistance Measurement

Offering the ability to measure the resistance without disconnecting the ground.

Ground Nomograph

Chart

Fall of Potential Plot

Worksheet

When is Ground not a Ground?

Grounding is a term that has many different facets, depending on the application.

Case Studies - Facility Management

Impact of Thunderstorms

As the first thunderstorms of the season begin to roll through, t is important to safequard your facility's equipment against the significant damage that can be caused by the high frequency transient energy of lightning strikes.

Stalled Motors

In this case study, we look at an industrial customer with two 1250 hp motors on a 4kV circuit, whose motors would not start.

Thumping Sounds in the Closet

Elevator control panels for the lower zone mid-rise elevators were on the nineteenth floor of a forty story office building in a large Midwestern city.

Computer on Shared Branch Circuit

A computer system used by laboratory personnel exhibited intermittent failures and data errors.  Typically these would start around 10 a.m.  On some days there were no failures.

Loose Bus Bar Bolts Cause Sags

An administration building in a government complex in New Jersey had a transformer with a 4kV primary, 120/208V wye, 800A secondary.  The bus duct ran up to a second floor panel, which supplied an office area.

Light Flicker in an Office Complex

The second floor of an end unit of an office-condo complex in the Washington DC area consisted of a reception and meeting area, two private offices, a kitchen are an a bathroom powered from a single three-phase 208/120V wye feed from a transformer bank located right below and outside the office.

Harmonic Distortion of Current

Office building with personal computers, terminals, copiers and other electric office equipment supplied by three-phase wye service.

Elevator Control Problem

Newly constructed condominium building in Westchester County, NY

Service Area Flicker

An entire service area of a Midwest facility.  the utility was receiving complaints of annoying light flicker from an entire neighborhood.

Handbooks

Fuel Cell Handbook

The fuel cell industry is currently undergoing initial commercialization of the technology.  Research and design, instrumentation and fuel cell performance testing is central to progress in this sector.  From the research and monitoring of various cell chemistries, to the design validation at the module and stack levels, to the system wide production test level, fuel cell testing faces unique challenges.  This handbook illustrates typical fuel cell test procedures and architectures.

Energy Star® and Standby Power Measurements

Many consumer products and appliances continue to consume a very small amount of power even after they are switched off.  These products include TV's and other devices with a remote control, VCR's, Computers, Printers, Microwave Ovens, products with Digital Displays, Cordless Phones, Cell Phone chargers, and many others.  Each of these devices consumes just a very small amount of power when turned off.  However, considering the billions of products that use standby power, the amount of electrical energy consumed becomes very significant.  The Federal Energy Management Program has established guidelines for measurement of Standby Power.

9000 Power Analysis Application Handbook

The main target applications for the DL9000 Power Supply Analysis Function are design and evaluation of power devices (semiconductors) and power circuits. Switching power supply technology depends greatly on MOSFET, IGBT, and other semiconductor switching devices. It is by

no means an exaggeration to say that switching devices are the determining factor of overall performance in switching power supplies.

Power Ratio

Adjacent Channel Power Ratio (ACPR)

Adjacent Channel Power Ratio (ACPR) Application Note Part Number 11410-00264.

UNDERSTANDING POWER FACTOR AND INPUT CURRENT HARMONICS IN SWITCHED MODE POWER SUPPLIES