The Energy Research and Development Administration believes the new design of a California inventor can save wear and energy in most of the electric motors in the United States that run on less than two horsepower.

The simple redesign electric motor windings invented by Cravens Wanlass means that no fewer than 500 million motors in use in the United States can rebuilt at a cost of about $56 apiece, ERDA said, saving their owners at least that much in power costs every year that they are run.

The kinds of electric motors that can be rebuilt with Wanlass' invention, ERDA's V. F. Witherill wrote to Deputy Assistant Administrator Gene Mannella earlier this month, include motors that circulate hot or cold air, that exhaust stuffy or contaminated air, that drive furnace and water pumps and that circulate swimming pool water or open garage doors.

Witherill told Mannella that the Wanlass motor was demonstrated by Southern California Edison Co. in no fewer than 11 different types of electric motor of less than two horsepower.

The McDonald-s Corp. told ERDA that it rebuilt all 60 motors with the Wanlass design in a restaurant in Santa Monica and was able to operate all the motors with less electricity, the motors included those for dishwashers, air conditioning and exhaust fans.

McDonald's said it ran a six-foot grill exhaust with the Wanlass design at the equivalent yearly operating cost $156.82. The Wanlss motor saved almost $66, mote than the $56 it cost to rebuild the motor with the Wanlass design.

The Wanlass motor involves an auxiliary coil winding wired in paralled to the existing motor's windings. This brings the current entering the motor in phase with voltage coming out of the motor, reducing the current needed to drive the motor.

Electric motors that would not be practical to rebuild with the Wanlass device include refrigerator motors that would cost too much to rebuild and those used in small tables saws that run on what engineers call a changing electrical load.