Squeezing more juice out of the electric motor

General Electric claims it may have one that will take some of the irksome chatter out your air conditioner. General Motors is on the trail of one that might put more zip into your car's windshield wipers.

And Harris Semiconductor, among others, is devising one that could give your table saw as many speeds as a mixer.

The source of all this attention? That ubiquitous and mundane workhorse of the appliance and industrial world, the electric motor.

Ever since the beginning of expensive energy in the mid-1970s, companies have been trying to find cheap ways of squeezing more juice out of the old electric motor. The goal has proved to be maddingly elusive: Observers recall, for instance, Exxon's ill-fated attempt in the late '70s to produce an economical, energy-efficient motor that was to save the equivalent of 1 million barrels of oil a day.

Now the race to produce a more miserly electric motor is picking up again - driven by soaring electric bills and the potential for using advances in electronics to improve the time-worn technology.

Why the interest? Because the nation's more than 750 million electric motors, toiling away in everything from washing machines to industrial compressors, are energy guzzlers. They consume some 58 percent of the electricity generated in the United States. That represents 18.3 percent of total US energy consumption - more than all the fuel burned in automobiles each year.

Several companies have recently come up with technological tricks that they claim could boost motor efficiency - and perhaps eventually trim some watts from the nation's energy bill:

* Both Harris Semiconductor, a division of the Florida-based Harris Corporation, and Chesebrough Pond's Inc. - yes, the maker of personal-care products - have produced new ''smart'' controllers for motors. These regulate the flow of power to the machine, in theory allowing it to use the right amount of juice for the job at hand.

Most motors waste energy because they run at one speed, no matter what the task: A drill press draws the same power when boring through oak as through balsa wood. Devices that automatically tailor the voltage to the load have been around since the mid-'70s. But most have proven too costly and inflexible for widespread use. Harris Semiconductor and Chesebrough Pond's believe they can fit motors with microchips that are cheap enough and ''sensitive'' enough to minor load fluctuations to do the trick. The systems face a stiff market test, but represent the kind of ''intelligent'' controls analysts expect most electric motors to be fitted with in the future.

* General Motors is said to be developing a new magnet that could have a far-reaching impact on the overall electric-motor industry. The company itself is tight-lipped about the project. Understandably so, since several competitors - including a big Japanese firm - are racing to hatch new magnets of their own.

If the auto giant is able to move the idea beyond the workbench, however, it could lead to a new wave of lower-cost, power-stingy motors in everything from refrigerators to industrial furnaces, industry sources say. ''We are watching it (the project) very closely,'' says Dr. Edward Cornell, a manager in General Electric's research and development center.

* General Electric, meanwhile, wants to change the ground rules altogether. While plenty of effort has gone into new materials and designs, the basic technology of the electric motor has remained virtually intact for a century. GE's new motor revives the idea of using direct current instead of alternating current to power conventional motors. The company says it has come up with a way to make a 40-year-old technology economical for everyday use. The new motor will use less juice, allow appliances to run at variable speeds, and operate more quietly, officials say.

All of these still face hurdles in the lab and marketplace. But they signal that the quest for a more fuel-stingy motor isn't dead. Indeed, the conservation ethic has already become somewhat ingrained among motormakers: Robert Hunt, an analyst with Arthur D. Little Inc., estimates that 20 percent of the industrial motors now being built are ''energy efficient.'' It is in the industrial arena that experts see the biggest potential for shaving watts. Still, it will be a long time before any of these efforts reduce the nation's energy bill much. Replacing machinery and home appliances, says Ewald Fuchs, associate professor of electrical engineering at the University of Colorado, remains a slow process.

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