Working out of a backyard laboratory, a California inventor has developed a new design for the standard electric motor that officials here today said could save the nation massive amounts of energy.

In an unusual joint news conference, California energy officials and officials of the Southern California Edison Co., the nation's fourth-largest utility, hailed the motor design as "a major, billion-dollar breakthough for energy conservation."

The invention, called a "controlled torque motor," reduces electric consumption by as much as 20 per cent while producing the same power out-put as conventional electric motors, according to its developer, C. L. Wanlass.

Noting that about 64 per cent of the nation's electricity goes to run electric motors, Wanlass said his new design could "make a significant impact in energy consumption in a relatively short time." He said he expects his motor to be on the market within a year.

The new motor design could be used to replace anything from a tiny motor in an electric shaver to a massive industrial motor, officials said. One utility official calculated that if the device became widely used among residential electricity consumers alone in the Southern California Edison system it would save about 1 billion kilowatt hours of electricity in a decade, or enough power to run a city of 300,000 people for a year.

The officials said electricity savings would be considerable greater for industrial consumers.

According to Wanlass, If a half billion electric motors were converted to his design, the nation could save between 1 million and 2 million barrels of oil a day, or roughly the daily production expected from the whole Prudhoe Bay Alaskan oilfield.

Existing electric motors could be modified for about $40 for a one-horse-power motor while the design could be incorporated in new motors with out increasing current production costs, Wanlass said.

Wanlass, 51, was formerly director of the Philco Corp's electronic research laboratories and holds patents on about 40 inventions, most of them in the computer field. He said he developed the controlled torque motor design in a laboratory in the backyard of his Santa Ana, Calif., home after leaving Philco in 1965.

Southern California Edison officials said they tested the device after Wanlass came to them last year. Under laboratory conditions the design saved up to 20 per cent of the electricity needed to run an ordinary motor, tility officials said. Larger energy savings could be anticipated in motors used under normal work conditions, the officials said.

California energy officials werentility officials said.

California energy officials were particularly enthusiastic about the prospect that the Wanlass motor could cut electricity use in home appliances. "We're hoping from this day forward the word Wanlass will be on the lips of a lot of people and it will benefit those people," said Robert Batinovich, president of the State Public Utilites Commission.

Another state energy official, Richard L. Maulin, said the results of tests on the Wanlass motor have been turned over the Federal Energy and the Energy Research and Development administrations.

Maullin said the new motor design may enable consumers to cut down on electricity use in home appliances, something President Carter called for in his energy message to Congress last week.

According to Wanlass, the redesigned motoruses additional copper winding and capacitors. The design achieves a more efficient transfer of energy into the motor while cutting down on energy loss 25 to 50 per cent.

"It's not an obvious design," he said "If you were to do it from scratch, it looks like a dumb thing to do."

The design is being tested extensively in several hundred motors in Southern California, Wanlass said. The McDonald's Restaurants Corporation has used 11 of the motors in their Santa Monica, Calif., outlet since February. A McDonald's spokesman at the company's Oak Brook, Ill, headquaters said their tests showed a 20 per cent or greater electricity saving from the motor.