Science & Technology
THE `DIRTY POWER' CLOGGING INDUSTRY'S PIPELINE
General Motors Corp. couldn't figure out why the computer running its minivan assembly line in Baltimore kept shutting down. But when it did, the factory would grind to a halt for hours. After months of detective work, engineers found the culprit: the local utility's old underground wiring. When new robots on the assembly line kicked in, the power drain caused voltage spikes and outages that shut the computer down. A backup generator solved the worst problems, but a permanent fix would cost millions. "We're groping for answers" to avoid such troubles all through GM, says engineer Ronald A. Smith.
So are lots of other companies. Nowadays, tiny power disturbances can generate big headaches. Power surges, sags, and outages, often less than a millisecond long, are nothing new, but they rarely fazed older equipment. Delicate computer chips with microscopic wiring are more susceptible. The results are burned-out equipment, scrambled data, and lost revenue.
In fact, problems from "dirty power" are short-circuiting some of the efficiencies automation promised. A blackout can cost manufacturers up to $500,000 an hour. Formerly low-tech warehouses and offices are vulnerable, too, now that they rely on computers. Power-related problems cost U. S. companies $26 billion a year in lost time and revenue, estimates Palo Alto (Calif.) consultant Jane M. Clemmensen.
VOLTERGEISTS. Power glitches can be maddeningly elusive. Often, they're caused not by storms, fires, or earthquakes, but by sources so obscure that Tandem Computers Inc. calls its power-quality engineers "ghostbusters." Normal utility load-switching operations that don't affect lighting or older machinery can send computers down if they're not specially protected. Industrial welding machines draw enough current to cripple personal computers a block away.
Most of the time, experts say, companies create their own problems. In 1986, new welding robots in Ford Motor Co.'s Chicago assembly plant created voltage spikes that burned out their own circuitry. Until Ford installed surge protectors, this electronic hara-kiri cost $250,000 a month. Faulty wiring is more common--and just as hard to find. At Master Circuits Inc., a Kokomo (Ind.) printed-circuit-board maker, a plating machine's voltage spikes, just a few millionths of a second long, blew out the company's waste-treatment system. The culprit: a hidden power line connecting the two.
Unfortunately, solutions can create new trouble. Improved power supplies for computers and other equipment extract more current from the socket, but they also cause interference. So do energy-saving variable-speed motors in new washing machines. "The better the equipment is, the more sensitive it is," says John Mungenast, editor of Power Quality magazine and a former General Electric Co. instrument designer.Some electronics manufacturers are trying to make sure the problem doesn't get worse. Emerson Electric Co., which makes battery-backed uninterruptible power supplies to keep large computers running during outages, is finding new markets in protecting desktop machines. Typically, such protection devices add 10% to the price of installing electrical gear. Clemmensen says the $2.2 billion U. S. market for such power-quality equipment is growing by 22% a year.
Meanwhile, chipmakers are focusing on building in protection at the microscopic level. Micro Linear Corp. in San Jose, Calif., sells a chip that smoothes out current to let computer workstations draw more power without overloading the line. Moreover, it stops the power supply from sending harmful impulses onto the line. Ixys Corp. of San Jose also has a new current-regulating chip.
After years of virtually ignoring the problem, many utilitites have started power-quality programs. The Electric Power Research Institute in Palo Alto is spending $2 million a year on programs such as studying whether utilities should offer higher-priced "clean" power for those who want it.
BLINKERS. That's partly in self-defense. Pacific Gas & Electric Co. began a power-quality program four years ago in California after a company whose computer center kept shutting down built a cogeneration plant to replace utility power. Utilities also serve more customers that have moved to the edges of metropolitan areas, beyond the traditional and more reliable power grid. Georgia Power Co., for example, provided an uninterruptible power supply when Confederation Life Insurance Co. moved to a new building on the outskirts of Atlanta.
There's another reason utilities have begun to make this a higher priority. Executives are getting tired of hearing from irate customers. "The real push comes from the blinking VCR machines," says Frank Young, director of EPRI's electrical systems division. "It's the little old lady who comes back from shopping and finds she missed her soap opera."Robert D. Hof in San Francisco