Control Engineering Motors, Drives, & Motion Control eNews for November 2002
Welcome back to the Motors, Drives, & Motion Control E-newsletter after a hiatus of a few months. We have some catching up to do given the rapid developments occurring in this dynamic arena.
Distributed control receives a helping hand
Distributed or ''decentralized'' control-a design method that locates the controller on or near the motor-offers cost savings due to reduced cabinet space, simpler installation from a cabling viewpoint, and more efficient maintenance for numerous applications. SEW-Eurodrive (Lyman, SC; Bruchsal, Germany) is boosting this movement toward distributed control with its Decentralized Control Technology (DCT), which it recently configured for North American applications and made available here. The company has previously used this technology with success in Europe, and reports up to 60% savings in installation cost from some manufacturers. A third-party audit in the U.S. found similar savings, using a conveyor line with multiple motors and variable-speed drives as a model.
DCT applies group motor installation provisions in the National Electric Code [Article 430.53 (c)] to cut costs via use of fewer branch circuits. The configuration is fully UL- and cUL-listed for group installations, says the company.
Other benefits of DCT for you to consider include:
Less costly branch circuit hardware and cabling, due to ability to daisy-chain power and bus transmission in one hybrid cable
Reduced field-control wiring by operating on common bus networks, such as DeviceNet, CANopen, Profibus, and Interbus
Convenient, low-cost sensor/actuator connection with local I/O points using M12 connectors.
Centralized vs. decentralized control
SEW-Eurodrive supplies all necessary components of a DCT system, built specifically for that technology. Movi-Switch is the part that incorporates switching and overload protection into a motor conduit box. Movimot integrates a frequency inverter (adjustable-speed drive) onto the motor. However, the inverter can also be located separate from the motor. The field distributor , a control enclosure mounted on the machine, maximizes functions of Movi-Switch and Movimot within a distributed control system using group motor installation.
For more information, visit seweurodrive.com
Control Engineering regularly covers distributed control developments. Some examples in the motor/motion arena include the following:
'' Integrated, Intelligent Motors & Controls Will Be in Your Future ,'' December 2001
'' Distributed Motion Control: A Worthy Option for Connectivity ,'' January 2001
'' Integrated Motor-Drives Seek Wider Market, User Acceptance ,'' December 2000
NanoMuscle NM125 actuator
Innovative forms of actuators, devices and systems, are making their way into practical products. Emulating biological muscles is one of the approaches taken. Here are two examples that may be useful to consider in your future designs.
NanoMuscle Inc. (Antioch, CA) announced in late-June 2002 the most powerful model in its Linear Actuator product line that offers an alternative to small electromagnetic motors and solenoids. NanoMuscle NM125 outputs 125 grams of force, a substantial increase over previously available units. See the Nov. 2001 E-Newsletter
Powered by shape-memory alloys, these actuators incorporate sophisticated electronics to control the force over the 4-mm stroke and provide various motion system functions. NanoMuscle NM125 offers silent operation, low power consumption, and reportedly has a lifetime of over one million cycles. This more powerful NanoMuscle actuator targets medical and security devices, consumer and business electronics, robotics, and aerospace applications.
For more information, visit nanomuscle.com
''Muscle Wire,'' is what Autosplice (San Diego, CA) calls its somewhat related innovation intended for a ''simple, low-mass, low-power, low-cost'' alternative to conventional solenoids (and related devices). Muscle wire employs nitinol , a family of intermetallic materials that consists of a nearly equal mixture of nickel and titanium, to which other elements are added to adjust or ''tune'' material properties. When electrically driven, nitinol takes on unique characteristics, such as shape memory and superelasticity . As a result, nitinol assemblies can flex like muscles, dynamically changing their internal structure at certain temperatures and return to their original shape when current flow stops.
Autosplice combines nitinol muscle wire with its insertion and splicing technologies for PCB assemblies. In one example, wire muscle is used to electronically trigger micro-latches for secure medical dispensing assemblies. The company has developed an automated process whereby clip-on tabs are spliced to the muscle wire, which is then attached directly to pins inserted into the PCB. It provides a simple electromechanical interconnect to hold the muscle wire consistently in the desired position and the electrical connection needed to drive its operation.
For more information, visit autosplice.com
3 recent market reports on ac drives, motion control
The North American market for ac drives should resume growth starting in 2002, after a double-digit fall in 2001, concludes a market research and technology forecast report by Drives Research Corporation (DRC, San Juan Capistrano, CA). Updated figures as of September 9, 2002 predict 2.2% market growth for ac drives in North America in 2002, followed by 5.4% growth in 2003. These figures are similar to those forecast in the February 2002 report ''AC Drives Outlook for North America 2002-2006,'' highlighted in my April E-Newsletter . Read a longer version in our News Archive .
''Combined with emerging new applications, we expect the billion-dollar-plus North American ac drives market to post a 5.9% CAGR over the next five years through 2006,'' says Thomas Kaporch, president of Drives Research and principal author of the 692-page report.
Given the large number of ac drive suppliers serving the North American market-currently more than 95 brands-they will need to find new ways to differentiate their ac drive offerings. ''The effort to deliver value differentiation by price, application-specific solutions, system integration, and distribution channel is expected to intensify,'' explains Mr. Kaporch.
For more information on DRC's ''AC Drives Outlook for North America 2002-2006'' report, visit drivesresearch.com
For the motion control industry, there will be no recovery in 2002, however, ''there is good news to follow'' in 2003, says the latest data from IMS Research (IMS, Austin, TX; Wellingborough, U.K.) dated August 2002. IMS predicts that the total North American motion control market will be worth $929.9 million in 2002, down from $1,154 million in 2000, which was a record year. IMS estimates a contraction of 17.5% occurred in 2001 for servo systems, stepper systems, and position controllers, which it defines as the motion control market. Stepper systems took the worst hit because of their heavy dependence on the semiconductor machinery market.
More positive indicators in the second half of 2002 indicate the start of a slow recovery, suggesting even better results for 2003, according to IMS Research.
For more information, visit imsresearch.com
Meanwhile, an ARC Advisory Group (Dedham, MA) report, ''General Motion Control Worldwide Outlook, Market Analysis & Forecast through 2006,'' released on Nov. 4, 2002, takes a similar view. It predicts a 5.7% CAGR (compounded annual growth rate) over the next five years, ''although the market will continue to decline through 2002.'' ARC's study sizes the general-motion-control (GMC) market at $3,976 million in 2001, forecasting it to be over $5,236 million in 2006.
These market numbers are obviously larger than in the above report, because they refer to global activity and include peripheral elements that make up GMC systems. Among extra elements needed are software tools to program, start-up, troubleshoot, and maintain GMC equipment, which although more functional also has become more complex. The need to connect GMC systems to the Web and the enterprise helps enlarge this market sector.
For more information, visit arcweb.com/research/auto/gmc-ww.asp
Absolute encoders stress resolution, reliability, compact package
They provide more accurate feedback and useful information than incremental encoders do, but in the past ''absolutes'' were more complex to install and configure, and more costly.
Acuro absolute encoders from Danaher Controls
A new series of compact absolute encoders from Danaher Controls (Gurnee, IL) seeks to change that image, while bringing higher resolution and novel reliability features to this product type. Dynapar Acuro single- and multi-turn encoders offer a choice of resolutions to suit the application in two basic versions. Acuro Industry provides up to 17-bit resolution in a single-turn version for various industrial applications, while Acuro Drive delivers up to 22-bit resolution as a motor feedback device. In multi-turn configuration, each has 12-bit resolution.
Thanks to low profile gears, installation height is only 45 mm for multi-turn models. The nonmagnetic gearset is immune to EMI and is said to be maintenance-free at continuous speeds up to 12,000 rpm.
Internal sensors enhance reliability. Optical sensors check the encoder signals' amplitude. A code check ensures that the encoder signal matches the recorded turn-bit by bit, says the manufacturer. A temperature sensor triggers at upper and lower limits set by the user, in the -40 to 100 °C range for Acuro Industry (-15 to 120 °C for Acuro Drive). Alarms and warning messages go to the control system if the limits are exceeded.
An integrated data storage feature allows detection and parameterization of individual encoders to speed up adjustment and assembly times plus provides self-monitoring for preventive maintenance. Communication formats range from parallel (gray or binary code) to networks, such as Profibus, DeviceNet, CANopen, Interbus, and SSI.
Acuro also simplifies the substantial task of zero (home) position setting for a high-resolution encoder. At startup, the reference position is determined electronically without the need to turn the encoder shaft to a defined position.
Simulation software tool from Integrated Engineering Software
More development tools are becoming available to designers of motion systems and related equipment.
''Electro, Magneto and Oersted'' simulation software promises to dramatically increase design productivity for electromagnetic, electromechanical, and power electronic components/systems. The software tool from Integrated Engineering Software (Winnipeg, MB, Canada) provides two-dimensional, rotationally symmetric field solvers that simulate electric, magnetic, and time-harmonic fields in high-voltage insulators, electric motors, solenoids, transformers, etc. It also can predict force, torque, capacitance, inductance, eddy currents, and other parameters vital to design. The latest Version 6 adds GUI and geometric modeler refinements, optimized solvers, and enhanced post-processing and visualization-to view real-time changes in the fields as a device moves or rotates.
For more information, visit integratedsoft.com
Motor innovations continue
New winding technology from ThinGap Motor Technologies.
Despite declarations by some that electric motors have become 'commodity items,' new motor innovations continue to reach the market through novel hardware refinements and new software tools.
For example, new winding technology from ThinGap Motor Technologies (formerly G&G Technology Inc., Ventura, CA.) reportedly eliminates eddy current and hysteresis losses to obtain high power efficiency over a wide motor-speed range. The patented armature coil assembly and thin-wall stator coil design uses precision machined copper sheets rather than circular wire. It eliminates the bulky iron core found in standard motors.
The technology is applicable to brush dc as well as brushless dc motors. In the brush permanent-magnet slotless motor version, ThinGap TG3300 Series delivers 80 oz-in. maximum continuous torque at 10,000 rpm, with 24 V dc and 27.5 A input. Weighing under 34 oz. (approx. 1 kg), the motor is rated at 0.8 hp (0.6 kW). An unusually high thermal rating of up to 160 °C also applies to these motors.
For more information, visit thingap.com
Another example of motor enhancement comes from SIB Engineering (Oceanside, CA) in a patented method that modifies a brush dc motor's armature with a ''power ring'' that contains three to six Zener diode semiconductors. The company's SIB (or self-inductance bypass) method claims to improve motor torque and power by 4-6%. It also extends the time between commutator resurfacing by a factor of 10. Independent dynamometer tests support the results.
SIB counteracts harmful effects of arcing on the commutator and brushes caused by the induced voltage that opposes current changes inherent in the rotating coil. Torque increase comes from bypassing the reactive current of commutation using SIB, which allows the changing magnetic field to aid rather than oppose incoming source current. The commutated coil can therefore react more quickly to torque demand.
For more information, visit prosilver.com
Control Engineering in print
Topics on motors, drives, and motion control appear each month in print. In case you missed our September and October issue, here are highlights. Next month's newsletter will catch up with coverage from the November and December issues.
Our September 2002 ''Product Focus'' addressed AC Adjustable-Speed Drives (ASDs), based on an online survey of CE readers' views and purchasing preferences for ASDs. Read the article
My October 2002 article, ''Chip-Based Motion/Motor Control Saves Time, Cost, and Space,'' looks at this emerging technology sector that allows designers and original equipment manufacturers to ''roll their own'' motion controllers, rather than rely on generic motion cards. Read the article .
An Online Extra article, ''Chip-Based Motion/Motor Control: The Way to Go for Some Users,'' adds more chip-level technology developments and describes available products. Read the article .
In the Products & Software section (Sept.) :
Alpha-Core Inc.'s (Bridgeport, CT) unusual ''o-ring'' shaped transformer cores offer size and weight reduction compared to standard toroidal cores.
Hollow-shaft 90 Series absolute encoders from Hohner Corp. (Beamsville, ON, Canada) provide parallel outputs up to 8,192 counts and accommodate shafts up to 60-mm diameter.
TorqueMate Plus torque analyzer from Mountz (San Jose, CA) interfaces with brushless rotary transducers, providing
Rockwell Automation (Cambridge, ON, Canada) introduces its PowerFlex 7000 ''A'' Frame medium-voltage ac drive with a smaller footprint that reduces installation space.
In the October issue:
Aerotech Inc . (Pittsburgh, PA) presents its ANT-4V High Precision Lift Stage capable of 50-mm/s speed and 200-nm accuracy.
Rotary positive displacement pumps from Viking Pump Inc . (Cedar Falls, IA) are presented as an alternative to ''centrifugals'' for fluctuating pressure or fluid viscosity applications.
Fairchild Semiconductor International (San Jose, CA) introduces an 18 N-Channel MOSFET (field-effect transistor) family with high thermal performance for its size and low package resistance feature.
Companies in motion
Encoder Products Co. (EPC, Sandpoint, ID) recently shipped its one-millionth encoder. The Ultra Heavy Duty 713-HD10 unit went to Ground Force Manufacturing LLC of Post Falls, located only 40 miles form EPC-a ''neighbor'' one might say in these parts. Ground Force has quite an unusual application. Its encoders monitor augers and pumps that mix components of explosives aboard specialty trucks it manufactures that deliver explosives for the mining industry.
Ormec (Rochester, NY) announced that effective Oct. 21, 2002, Edward J. Krasnicki, Ph.D. became president and ceo. The move culminates recent restructuring at the company. ''In his new role, Dr. Krasnicki will assist Ormec in developing and implementing the company's strategic direction,'' according to the announcement. Ormec is a supplier of PC-based motion-control technology, including a recent product introduction called ServoWire SM, which is a new approach to ''soft motion'' control.
On Oct. 18, 2002, Danaher Corp . (Washington, DC) announced that it has completed the purchase Thomson Industries Inc. (Port Washington, NY), a leading U.S. producer of motion control products, including linear actuators, ballscrews, linear bearings and rails, and precision gearboxes. Danaher is a leading manufacturer of process/environmental controls, tools, and components. The corporation includes Danaher Motion division, which intends to combine its existing linear actuator and component businesses with Thomson.
Also on the acquisition front, Sick AG (Waldkirch, Germany), a leading producer of sensors, safety systems, and identification solutions for factory automation, along with products for process analysis and environmental measurement, announced its takeover of Max Stegmann GmbH (Donaueschingen, Germany)-a major name in shaft encoders and actuators for automation technology-effective Oct. 1, 2002. Each company had a subsidiary in the U.S., which ''will continue to operate independently,'' as Sick Inc. (Bloomington, MN) and Stegmann Inc. (Dayton, OH).
For a longer version of this item, see CE Europe, Oct. 2002
Earlier in the year, Motion Engineering Inc. (MEI, Santa Barbara, CA) announced that SynqNet digital communication interface for synchronous motion-control applications is being supported by servo drive products from Advanced Motion Controls, Danaher-Kollmorgen, Matsushita Electric Industrial Co. (Panasonic), Tamagawa Seiki Co., and Yaskawa Electric, as well as MEI. SynqNet, developed by MEI, has more than 150,000 servo axes designed into next-generation machines intended for the semiconductor, electronic assembly, and robotics industries, according to MEI. SynqNet is built on 100baseT physical layer and connects to servo drives in the 50 W-10 kW range.
For more information, visit the following Web sites:
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