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MOTORS
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 | Motors & Pumps: Airing the Options
For engineers designing pressurized air or vacuum systems, it’s important to understand that no single air-pressure or vacuum technology is optimal for all applications, as illustrated by the comparisons shown in Fig. 1 and Fig. 2. To help narrow down the choices, engineers can peruse charts for flow, pressure, and vacuum that are widely available from pump manufacturers. Before starting the process, however, it is helpful to be acquainted with the chief characteristics of the most common pump technologies used by equipment designers.
by David C. Droege
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 | Fans & Blowers: Optimizing Flow (June 2008)
Appliances have issues. Flow and thermal issues to be
exact. The movement of air, water, and other fluids at proper temperatures is
vital to every appliance. Adding the ever-increasing demand for efficiency and
environmental controls yields complex interactions that can determine the
success or failure of a new or updated product.
by Jeff Waters
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 | Electronics: Digital Multitasking (June 2008)
Appliance technology has evolved significantly over the years, and two trends are merging to fuel the next round of appliance evolution — digital motor control and digital sensor processing. Digital Signal Controllers (DSCs) are at the confluence of these trends, and they enable digital sensor processing, digital motor control and power factor correction to be implemented on a single chip.
by Steve Marsh
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 | Quality & Standards: Modern Motors (May 2008)
Why is UL changing its motor standards? This is
generally the first reaction when people hear that UL is changing its venerable
UL 1004 and UL 2111 standards for electric motors. Part of this reaction is due
to the perception in some quarters that UL serves as the “Safety Police.”
Another part of the reaction may be due to the comfort level that engineers
have with the previous set of requirements that were first printed in 1972 and
are well recognized by manufacturers.
by Frank Ladonne
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 | Motors: Drive Decisions
The AC induction motor has dominated appliance
applications as the prime-mover for many decades. Most of these applications
used relays for on-off control of split-capacitor AC induction motors.
Mechanical transmissions provided changes in speed and direction. However, many
modern appliances, including clothes washers, HVAC, refrigeration appliances,
and others now take advantage of variable-speed motor drives to improve their
functionality and energy efficiency – all while improving performance,
reliability, and cost.
by Eric Persson
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 | Motors: New Basis for Brushless
For a couple of decades, appliance makers have
been trying to justify the added cost of brushless DC (BLDC) motor replacements
for brush and AC motors. In general, only high cost/high-reliability
applications have been able to justify the change based on reliability and
performance factors such as speed control, torque ripple, jitter, and EMI.
by Brad Marshall
Christian C. Petersen
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 | Motors: Coolly Efficient
Commercial refrigeration efficiency is a hot
button issue as government regulatory agencies draft and enforce new energy
efficiency standards and end users want more powerful, less energy consuming
equipment. As a result, designers of refrigeration products are increasingly
eyeing electronically commutated motors as a key path to increased efficiency.
by Larry Adams
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 | Motors: Extending Efficiency (Oct. 2007)
Advanced motor-control techniques are a practical
necessity because they enable more efficient and quieter appliances. In the
past, these advanced control techniques were only available as proprietary
solutions, and hence were limited in scope to a few high-end appliances. Given
the drive toward efficient appliances running on “green” power, which is
mandated by regulations and customer preferences, these motor-control
algorithms are now being sought by designers of all classes of appliances.
Thanks to the new generation of digital-signal-controllers (DSCs), the
cost-effective implementation of advanced motor-control algorithms has become a
reality.
by Jorge Zambada
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 | Motors: Double Duty (Oct. 2007)
Advances in power and
digital control silicon technology over the past few decades have enabled a
continuous improvement in motor-drive technology. When permanent-magnet,
brushless-motor drives were first introduced to the market more than 20 years
ago, the control algorithms were implemented using a combination of analog
amplifiers and logic components. Today, highly integrated, mixed-signal
controllers enable the implementation of complex control algorithms that
maximize the efficiency of permanent-magnet AC motors.
by Aengus Murray
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 | Motors: Optimizing Performance (July 2007)
According to the U.S. Environmental
Protection Agency, electric motors account for over 60 percent of the electrical
power consumed in the U.S., equal to over 1.7 trillion kWh per year, worth over
$100 billion per year (at 6 cents per kWh). More than 80 percent of this power
is consumed by motors larger than 20 HP, which are less than 1 percent of the
country’s installed motor population. Each 1 percent improvement in motor
efficiency results in a savings of over $1 billion in electrical energy costs, 6
to 10 million tons less per year of combusted coal, and approximately 15 to 20
million tons less per year of carbon dioxide released into the atmosphere.
by Thomas Kaporch
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 | Motors: Bearing Up (July 2007)
Rolling
element bearings in electric motors generally serve to support and locate the
rotor, keep the air gap small and consistent, and transfer loads from the shaft
to the motor frame. Applications abound in consumer appliances.
by Daniel R. Snyder
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 | Motors: Efficiency Controller (April 2007)
Many
appliance motors operate inefficiently. Single-phase AC induction motors,
particularly in the fractional horsepower range, are naturally inefficient.
Furthermore, most manufacturing techniques used to improve natural motor
efficiency (iron reduction, improved lubrication to reduce friction, etc.) are
either not applicable or prohibitively expensive for these motors. For these
reasons, most of the effort in improving appliance efficiency has centered on
other areas of the system. For example, most refrigerators are able to achieve
energy reduction (and thus the coveted Energy Star rating) by improving the
seals, insulation, and airflow paths. Until very recently, little effort has
been expended on improving the efficiency of the compressor motor itself. The
same holds true for most appliances using an AC induction motor.
by John Hurst
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 | Motors: Emerging Concepts (April 2007)
Many
areas of appliance design have experienced significant changes during the past
10 years. Electronic controls and electronically controlled and commutated
motors have proliferated. Modern clothes washers come with DVD instructions and
they feature elaborate, microprocessor-based control systems.
by George Holling
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 | Motors: Single-Chip Solutions (April 2007)
Electric
motors are by far the biggest consumers of energy produced in the world.
According to the Department of Energy, of the total energy produced in the
U.S., about 60 percent to 65 percent is consumed by electric motors. Among the
largest components of this are home and commercial refrigeration appliances and
HVAC systems. It is estimated that by building more efficient drives, the U.S.
can save about 25 percent in home refrigeration costs, 80 percent in HVAC costs
and about 60 percent in pump and fan control costs.
by John Pocs
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 | Motors: Precision Pumping (January 2007)
In the realm of medical motors, pumping is one of the more common applications. Because of the need for sealing and or motor isolation, and the variety of pumping methods available (see sidebar, Pumping Technologies), pumps are typically sold as packages, with the appropriate motor matched to the appropriate pump head.
by Larry Adams
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 | Motors: Medical Motion (January 2007)
When designing a medical pump that is meant to administer the correct dose of medication to a body at the right time, precision, reliability and repeatability top the list of musts. If it’s a stepping motor application, the motor rotates the exact number of steps. It must make the lead screw drive the syringes in exactly the right amount. And, it must do it every time at the right time and at the right amount.
by Larry Adams
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 | Motors: Controlling Cooling (January 2007)
Power conversion is being used in many everyday appliance products, including microwave ovens, washing machines, air conditioners and refrigerators. With many more sophisticated applications arising in conjunction with energy saving and cost reduction, more advanced control technologies like field-orientated control or load-adaptive control for motors have been developed. Performance for these advanced controls are generally unattainable via standard 8-bit microcontrollers due to lack of either signal-processing capabilities or suitable peripherals. Recently, however, this situation has changed dramatically through utilization of DSP-based controllers. The architecture of a Digital Signal Controller (DSC), which includes both digital signal processor (DSP) and microcontroller (MCU) functions with sophisticated on-chip peripherals, was designed to reduce component usage and system cost as well as advance processing power.
by Charlie Wu
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 | Motors: Driving Progress (October 2006)
Motor drives in household appliances are becoming increasingly sophisticated to meet the challenges of higher efficiency, increased reliability, and lower cost. Recent developments in the motor drives and the power components that they contain are helping to fuel this trend.
by V. Sukumar
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 | Motors: Compact Control (October 2006)
The transfer molded DIP-IPM (Dual-in-Line Intelligent Power Module) was first introduced by Mitsubishi Electric in 1998 to address the growing demand for cost-effective motor control in consumer-appliance applications.
by Eric R. Motto
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 | Motors: Sensorless Simplicity (July 2006)
Recent worldwide trends are toward a more widespread use of permanent-magnet synchronous motors in appliance applications. Global raw-material-price increases in aluminum, copper, and steel have driven this trend and have shifted the cost advantage away from induction motors, which are less efficient and more bulky than permanent magnet motors. The application of direct-drive permanent-magnet motors in clothes washers improves the system dynamics and saves cost due to a simpler mechanical structure.
by Aengus Murray
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 | Motors: Cost-Effective Quiet (July 2006)
In most air-moving applications that employ a fan, such as vacuum cleaners, the only resistance experienced by the motor at start-up is the static friction of the bearings and the brush gear. The fan creates a load only when it is running, and the load is in proportion to angular velocity.
by Roger Baines
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 | Motors: Pool Patrol (July 2006)
Pools may be for pleasure, but keeping them in top working order is a lot of work. The eMod electronic, mode-sensing module, from A.O. Smith Electrical Products Company, Tipp City, Ohio, alleviates some of the headaches that come from pool and hot tub ownership, by detecting problems that could shorten the life of the motor.
by Karen Buscemi
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 | Motors: Quieter by Control (April 2006)
Permanent magnet synchronous machines (PMSM) are a popular choice for high performance variable frequency drives. Their advantages include a high torque-to-inertia ratio, power density, and efficiency. Although the advantages are numerous, a design challenge often faced when utilizing PMSMs is that they produce significant torque harmonics.
by Steven D. Pekarek
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 | Motors: Spinning FREE (April 2006)
Few markets are more competitive than the one for large screen televisions. In that segment, even a slight technological advantage can provide a cost reduction that sends sales soaring. When studying one of the product lines in that segment, Shinano Kenshi discovered a means to provide such an advantage.
By Sawato Aizeki and Albert Melshenker
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 | Motors: Managing by Module (April 2006)
Today's engineers must learn to prosper in an environment that emphasizes a plug-and-play design strategy. Most major appliance manufacturers, for example, have adopted the practice of considering even critical electronic subsystems (such as a motor controller) simply as a component.
by Jeffrey Reichard and Andrew Soukup
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 | Motors: Axial Advantage (April 2006)
Recent events have made energy production and the efficiency of energy utilization the subject of much discussion, especially during the past few months. This interest will probably continue and will likely have widespread effects on the appliance industry. Specifically, motor efficiency, especially small motor performance, is being re-examined and regulated through overall appliance energy usage standards.
by John Petro
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