Page 26 RAIN Jan./Feb. 1984 TINKERING AND INFORMING: Appropriate Technology in Action by Kris Nelson and Ann Borquist People undertake energy-conserving projects for a variety of reasons. Some, like Cynthia Stull, seek a more cost-effective, yet renewable fuel for heating. Some, like the Association of Oregon Recyclers, have ecological concerns as well. Others prefer to empower project innovators and the public with information on appropriate technology. And a few, like Richard Propp with his electric car, just like to tinker at energy- efficient designs. Whatever the individual reason, the desire to try out non- fossil-fuel-consuming technologies underlies all of them. Such was the basis for the creation and awarding of the U.S. Department of Energy Appropriate Technology Small Grants. As the last in a series offive articles, we describe four A.T. Small Grants projects in Oregon. —KN Richard Propp test-driving his aerodynamic electric car. Electric Vehicle Even pogo sticks may cost more to “fuel” than Richard Propp's electric vehicle. For a 55-mile trip, the two- person car uses a meager 16 cents worth of electricity (based on two cents per kilowatt hour). At three-tenths of a cent per mile, he's left filling stations, carbon monoxide, and OPEC far behind. For nine years, Propp has fiddled with and tested, built and rebuilt his electric vehicle. When he was awarded an A.T. Small Grant in 1979, he knew what he was after; an ultra-light, battery-powered car that would be simple to operate and maintain, inexpensive to use, adaptable to the energy needs of long and short trips, and suitable for production. He pioneered innovations with battery use, the motor-transmission system, and the body design. Using the chassis of a 1956 Volkswagen Beetle, Propp minimized the car's weight—the most effective way to reduce energy use—in two ways. First, he constructed the body with fiberglass and foam. Second, he installed 12 batteries that deliver 12 volts each rather than the more commonly used 18 batteries that deliver six volts each. This cut the battery weight by some 480 pounds. Moreover, the batteries are situated so that any number can be removed or added according to the trip's approximate distance. Although he contends he "didn't do anything magic,” Propp devised a drive system that maximizes operating efficiency. He discovered that his motor ran most efficiently between 1,800 revolutions per minute and 3,000 rpm. Other electric cars are designed to operate between zero and 4,000 rpm, far beyond the range of energy efficiency. He designed the transmission, an automatic belt system similar to those found in snowmobiles, to automatically select the gear ratio that keeps the rpms within the optimal range of efficiency. The motor was modified for efficiency and ease of maintenance. It operates without an expensive silicon control rectifier ($1,000 to $1,500), a device that feeds voltage to the motor's rotating armature in pulses. Such a rectifier system causes the batteries and the motor to pulsate and frequently induces failures in electric vehicles. Instead, Propp's direct current motor controls the electricity through its field—the stationary portion that surrounds the armature. "The field acts like a speed amplifier," says Propp. It enables the motor's base speed (1,800 rpm) to start within the range of optimal efficiency, whereas the silicon rectifier engages the motor at zero rpm—below efficient operation. His field-controlled motor affords other cost-saving advantages. It utilizes simple transistor circuits. These are easily checked for malfunction and are inexpensive to replace. Most electric vehicles using a silicon rectifier system require pulse circuits that must be tested with an expensive oscilloscope. The replacement cost is also high. Propp's attention to energy efficiency is most evident in the vehicle's streamlined body. It closely conforms to the principle that a vehicle should "open up" the air and
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