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Articles from 1998 In August


Small vector control drive

Siemens' Micro Master Vector and Midi Master Vector Variable Frequency Drives (VFDs) are reportedly the first to integrate sensorless vector control into the small dimensions of a standard frequency controller. The two units are smaller in size and offer more standard features than their VFD predecessors. They are also compatible with standard induction motors ranging between 1/6 to 100 hp. Introduced in 1993, the Micro/Midi Master drives were among the first VFDs to offer breakthrough technologies, such as flux current control for automatic current load adaption. In their latest iteration, the controllers' sensorless vector inverter capability derives from a new ASIC that quickly calculates rotor speed and position. This enables the rotor and stator current to be controlled for optimized performance. Siemens Energy & Automation Inc. Product Code 4362 (P)

Increased horsepower capacity

Reliance Electric's enhanced FlexPak 3000 digital dc drive offers increased capacity to 600 hp. Operating on three-phase ac input power, the FlexPak 3000 drive operates with regenerative and non-regenerative applications. Other new enhancements to the unit include a DeviceNet communications card and an I/O expansion card. The DeviceNet card allows a FlexPak 3000 to communicate over the open protocol DeviceNet network. The card mounts inside the FlexPak 3000 and includes terminals for network connections. It has the ability to modify parameters, plus operate and monitor the FlexPak 3000. Rockwell Automation, Reliance Electric. Product Code 4363 (P)

Encoder encompasses Hall sensor function 8-17-98

August 17, 1998 Design News

FEATURED PRODUCT

Encoder encompasses Hall sensor function

Geoff Nairn, Spain


A compact encoder series from Eltra s.r.l. simplifies control of brushless dc motors by combining incremental encoder and motor phase control in a single device. The EF encoder series optically generates the motor phase signals that in a traditional brushless DC motor are produced by Hall effect sensors mounted in the motor body.

In addition to the standard output signals of a conventional incremental encoder--resolutions from 200 to 2,048 lines per revolution are offered with or without zero index--the encoder disk of the EF series has three extra tracks to optically simulate signals traditionally generated by Hall-effect sensors. According to the phase angle between these tracks, the encoder can control DC motors with 4, 6 or 8 poles.

Eltra believes its new encoder offers several advantages over relatively expensive Hall-effect sensors located inside the motor case. The new encoder, for example, is typically located in a cooler, less hostile environment at the end of the motor shaft.

By eliminating Hall-effect sensors from the casing, design engineers can produce cheaper, more compact motors with simpler wiring. This, in turn, helps reduce electromagnetic interference.

Compatible with leading commercial digital drives, the encoder can be mounted on motors with shaft-hole diameters of 8, 10, 14 or 15mm. Hall Effect phase outputs can be configured as NPN open collector or line driver outputs. Power supply options are 5V or 8-24V.

Additional information, contact: Andrea Pedron, Eltra s.r.l., Via Monticello di Fara 32 bis, 36040 Sarego (VI), Italy. Tel: +39 0444 436489; Fax +39 0444 835335.

Measurement and control equipment

Precision measurement and control equipment includes linear and rotary encoders, CNC controls, digital readout systems, and digital height gages. New models of these product types include the Manual Plus M lathe digital turning control which is equipped with an integrated drive package for controlling two axis plus spindle. New gages include the ST 12 incremental length gage from the company's SPECTO program and the MT 1201 and MT 2501 length gages from its METRO program. Sealed and exposed incremental linear scales are also available.

HEIDENHAIN Corp.

Booth 4458

115 Commerce Dr.Schaumburg, IL 60173FAX (847) 490-3931

Microsize drive for 460V ac

MagneTek's microsize GPD 205 adjustable frequency drives are now available in 460V ac models. The new models come in four incremental ratings from 0.5 to 3 hp. Although only a fraction of the size of conventional PWM drives, the GPD 205 is said to be useful for sophisticated equipment control in applications that include fans, pumps, mixers, agitators, compressors, conveyors, commercial laundry, and material-handling installations. The drive's 16-bit microprocessor provides the flexibility, features, and performance for a wide range of operational requirements. It installs and programs easily, has the versatility to adapt to simple or complex applications, and is UL-listed, CSA-approved, and CE-marked. MagneTek Drives & Systems. Product Code 4361

Interbus chip makes bus design easier 8-17-98

August 17, 1998 Design News

FEATURED PRODUCT

Interbus chip makes bus design easier

Michael Babb, London


OEMs who want to build small Interbus systems for specialized applications now have a low-cost integrated circuit which simplifies the design task. Called Interbus UART, the chip allows users to cost-effectively configure their own Interbus masters for systems that may involve as few as six intelligent factory devices.

Typical Interbus systems consist of hundreds or even thousands of nodes, usually hosted by a PC or programmable controller. This requires a "master" controller card with an Interbus ASIC, a Motorola 68332 microcontroller, and Interbus firmware.

By contrast, the Interbus UART implements the same master controller functions, but works with any microprocessor and uses free software available from the Interbus Club's web site. It does not have the functionality of a full master, but is suitable for scaled-down systems.

"We developed the UART chip to cover all the small and simple solutions where a bus system is needed," explains Dipl.-Ing. Martin Müller, manager of system marketing for Phoenix Contact. "For example, drive manufacturers told us they wanted to connect several drives together to build multiaxis motion control systems. Previously, their only option was to use CAN chips and build proprietary solutions, because the Interbus master card was too sophisticated and expensive for them."

For additional details, contact Phoenix Contact GmbH & Co., P.O.B. 1341, D-32819 Blomberg, Germany; Tel: +49 52 35 34 1845; Fax: +49 52 35 34 1825 or http: www.interbusclub.com

Linear actuators

GS Series linear actuators combine a brushless servo motor with an inverted roller-screw mechanism to produce an integrated, all-electric, compact sealed linear actuator. The actuators provide continuous thrust ratings from 100 to 8,000 lbs and speeds to 40 inches/sec. Frame sizes range from 2 to 6 inches. GS actuators are available in a wide variety of stroke lengths, sizes, speeds, and mounting configurations.

EXLAR Corp.

Booth D24030

1450 Park Ct.Chanhassen, MN 55317FAX (612) 470-6290

Machine vision system

The F30 machine vision system incorporates a camera lens, lighting, and processor into a 3 x 3 x 6-inch assembly. This system fills the niche between high-end photoelectric sensors that cannot detect two dimensions and which require adjustments as applications and/or products change, and basic vision systems that require programming and considerable set-up time. The F30 is for inspection applications such as presence/absence, orientation, parts sorting, and detecting foreign material in objects or their packaging as they are being manufactured.

OMRON Electronics Inc.

Booth D24387

1 E. Commerce Dr.Schaumburg, IL 60173FAX (847) 843-8081

Managing design 8-17-98

August 17, 1998 Design News

MANAGING DESIGN Tips on guiding product development

Design for survival

Brad Wendt, President Design Concepts Inc. Madison, WI


An article of faith in engineering and design is that we never lose sight of the basics. We learn early that a mechanical device will hold up over time and under stress only if its author has embraced such fundamentals as proportion and balance of simplicity, quality, and serviceability. At Design Concepts Inc., we were thrust into a situation that eventually gave us new confidence in our own abilities. If your company faces a life-threatening business crisis like ours, get down to basics quickly and leave nothing to chance.

My father, David Wendt, founded Design Concepts Inc. as a design and product development company in 1970. We've grown steadily, and now our employees work with major players in world markets. In 1995, we were looking toward the close of a successful year. Two challenges plunged us overnight into a survival crisis.

Crises. The first challenge hit December 15, 1995, when two key managers walked into my office and resigned to enter business for themselves--with a Design Concepts client and proposal information in hand. Three other staff members and a sales agent soon followed, in a coordinated defection. Two weeks later Design Concepts Inc. founder and chairman David Wendt suffered a stroke while skiing and fell into a coma. He did not recover from the coma and died one week later.

Very rapidly, the company had lost 33% of its billing capacity, faced spirited competition, and felt the loss of project assignments from clients. Internally, ongoing projects were at risk, with eight professional staff members suddenly forced to work without direct supervision. Morale was a pressing concern; employees were apprehensive. The company that David Wendt had built now faced a very real threat to its life without his guidance or a management transition period.

Resolution. Management adopted a three-point strategy. It would focus on the core business, delegate downward, and recruit aggressively.

Early on, the team closed a Florida branch operation and an ancillary company in Wisconsin. Managers met extensively with clients to shore up goodwill and to reassure them that design programs in progress were being managed without relaxation of time and quality standards.

Staff members carried unusually heavy loads, often working long hours without direct supervision, and at times taking on management-level tasks and responsibilities. Meanwhile, we attracted two key managers. In total, Design Concepts lost six people and hired seven.

The three-part strategy emphasizing the basics was clearly successful. Beyond merely surviving, we came through the crisis better off in several ways. Sales and profits for 1996 and 1997 were up substantially. We now have up to 30 employees. Our work has expanded geographically to include our first major project in China, and we're working in a much greater variety of SIC codes. While part of this is due to having moved so aggressively to make up the lost core business, we also know we're doing a better job of managing projects and serving customers, as measured by repeat business.

One additional benefit doesn't show up on the books. The people who stayed say that Design Concepts is now a fun place to work. 

In 1997, Design Concepts Inc., was awarded a Blue Chip Initiative Award by the U.S. Chamber of Commerce.


Q: It's difficult to argue against the logic of planning before a crisis, but for a small company, how realistic is it to plan for the unthinkable? And where do we start?

A: Begin by saying you're not going to commit massive amounts of time and resources to creating a plan. Then imagine the worst two or three things that couldhappen, and try to figure what you would do if one of them did happen. Decide what is actually essential to your company, have a backup strategy for each essential operation, and a succession path for every function.

As to it being realistic, crisis planning can make a terrific subject for an in-house seminar, because it requires managers to prioritize tasks and functions according to their contribution to the company. A crisis plan might suggest more effective day-to-day allocation of your resources.

Q: How can a small company protect itself against the sort of crisis that is caused by the sudden resignation of key personnel?

A: Two ways. First, have a succession track for every position and make grooming what I call a "strong second" part of every manager's job. If you do this openly and candidly, from the beginning, it shouldn't be a problem, especially if you make it a part of the ongoing crisis plan.

Second, and this is more difficult and more important, try to make your company a place where people want to stay, or when they want to move on, to leave with grace. As long as we have a free society, people will be changing jobs for one reason or another. When a staff member or manager wants to move for career advancement or geographical change, or whatever reason, that person should be able do so with management's blessing.

Fax your management questions to Design News at (617) 558-4402 or e-mail your question to [email protected] 

Letters to the Editor 8-17-98

August 17, 1998 Design News

Letters to the Editor

Readers state their views


Furniture airbags

Your satirical article, "Will furniture airbags soften the blow?" (Breaktime, 5/18/98 issue) should emphasize that these airbags are to be used as a supplemental restraint system only. The real protection is provided when chair occupant uses his/her suspenders as seat belts.

Branislav Kovacevic
AlliedSignal Canada Inc.


Air bags for furniture, you've got to be kidding! What happens once the air bag is deployed? Do you throw the furniture away? Do you send it out to the neighborhood furniture store to have a new bag installed?

I think the helmet idea is almost a good one. How about a portable air bag that can be worn instead of the helmet? It would resemble a head band, with an air bag in front, one for the back of the head, and one on each side. You're protected all the way around, no mater what the situation.

No more cracked heads when two people bend over to pick up the same item. Getting a file from the bottom drawer of a file cabinet and hitting the back of your head on the top drawer that is always open. Or hitting the back of your head when you go to pick up you pen that fell underneath your desk. Joggers can use it for low tree limbs. How many times have you fallen off your favorite bar stool at your local pub during happy hours? Tall people going though doorways. There are endless ways of hitting your head, and I think the Head Band Air Bag is the way to go. Can be sold individually or packs of 12 or by the case.

Thanks for hearing my suggestion.

Ray Olea
QA Manager
Dow-Elco Inc.


'Sizing' up the safety debate

I heard on the news that the death rate in small cars is approximately the same whether they are hit by a SUV or another small car. I do not remember the name of the study but I believe it was by the federal government.

As for why I choose a large vehicle, I am 43 inches tall sitting down! I have not been able to find a new car with sufficient headroom since the '70s.

Bob Yates


Metric debate goes on

I hope that J.C.R. Forehand was being facetious (Letters, 6/8/98), but I suspect not.

As for a unit of measure corresponding to roughly a foot, I propose the light-nanosecond (approximately 11.811 inches). Unlike a foot, it could be directly measured in a well-equipped laboratory anywhere. It doesn't "solve" the polysyllable nomenclature gripe, but that's a straw-man anyway. Context is routinely invoked to eliminate speaking the units of measure. If I say to someone around here that I was driving 65, I don't have to say "miles per hour"--it's understood.

If I said I'd been driving a hundred on the Autobahn to someone who thought in metric, he or she would probably assume I meant kilometers per hour without any need for me to say the words. The written abbreviations for the units don't differ much between systems (and just to claim that English measure is systematic, with hundreds of different internal conversion factors!).

Ron Darner

Reader J.C.R. Forehand misses the point entirely. The independence of the units, therefore, the lack of fractions, is exactly the beauty of the metric system. It would pay for itself just for not having to teach fractions in school, even if all the rest of the world didn't use it.

Horace Smith
Documentation Engineer
Syntron, Inc.
Houston, TX


Design News' website

I just wanted to compliment you on what must be one of the best websites I have ever experienced (GREAT JOB!!!).

My hope is that the Design News website becomes known as setting the standard for no-nonsense efficient communication of relevant information.

I am indeed as impressed with this website as I have been with your already excellent magazine.

David Lefavour
Master Engineer
Sundstrand Aviation

Correction: In the Technology Bulletin (Design News, 6/8/98, p.22), an item on "nanophase" materials--microscopic composites that have the potential to create superior protective coatings-- drew wide response from readers. The correct name of the individual heading up a two-year study of nanotechnology is Richard W. Siegel, a professor of materials science and engineering at Rensselaer Polytechnic Institute.


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