The only light left shining at 4 a.m. in this quiet Southern California suburb was in the little laboratory behind a garage where Cravens L. Wanlass was finishing up tinkering with the electric motor he built out of $100 in spare parts and the brake off a Schwinn bicycle.

"I turned it on," recalled Wanlass who is called Chris by friends and business associates, "and, by golly, the thing did what it was supposed to do. I shouted and woke up my family and we all clapped and danced around a lot."

That was a couple of years ago - he won't say how many years because he is still worried someone will come along and claim they thought up the idea first - and Wanlass has since put his little motor in a locked vault.

"Maybe," he said with a little embarrassment recently, "someone will want to look at the first someday."

If the experts who have examined Wanlass' invention are correct, there are likely to be quite a few more like the first one. Although about 50 million alternating current motors are manufactured annually - to run everything from eggs beaters to steel mills - Wanlass' is the first major design improvement since the first electric induction motor was designed by Nikola Tesla more than 80 years ago.

Perhaps even more important, Wanlass' motor - which is called a "controlled torque motor" - promises the saying of vast amounts of energy at a time when energy conservation is beginning to preoccupy nearly everyone.

In a study done last year for the Federal Energy Administration, the Arthur D. Little Corp., a Cambridge, Mass., independent research firm, calculated that about 64 per cent of all the electrical energy generated in the United States goes to run motors in business, industry and private homes.

At a recent news conference to announce development of the controlled torque motor, utility officials distributed figures showing that there are 250 million motors in the United States that could be converted to Wanlass' design.

The officials estimated the average motor could save more than 20 percent in electrical consumption with the new design, a saving they said could conserve an estimated 50,000 megawatts in power plant output and 1 million to 2 million barrels of oil in the United States daily.

Those kinds of figures have generated considerable interest in Wanlass' design. Since the new conference April 25, more than 400 telephone calls - including one from the Soviet Embassy in Washington - have come in to Wanlass or his attorneys. Most of the calls, they said, have been from people or businesses anxious to get in on what they see as the ground floor of a major technological breakthrough.

The invention promises to make Wanlass a wealthy man. For the 51-year-old inventor it is a long-awaited payoff after years of watching his financial reserves drain while he dogedly pursued an clusive electro-magnetic concept that is no complex some electrical engineers admit they don't fully understand it even after Wanlass explains it to them.

The tale of Wanlass' development of his motor is a peculiar Southern California adaptation of the old Horatio Alger theme.

In 1965 Wanlass was already a successful businessman, a research scientist who with seven colleagues, had quit the Lockheed Aircraft Corp, and formed an electronics company in Southern California's booming Orange County. The firm was bought out at a handsome profit to its founders by the Philco Division of the Ford Motor Co.

Wanlass said he became restless working for Philco. "It was a good company but I felt I could have more freedom on my own," he said. "I had been in computers since the era started but the real creative part had slowed down. It didn't take much to see that the next big challenge was going to be in the energy field."

After leaving Philco and researching the subject at a college library near his home, Wanlass said he discovered that it takes more fuel to supply the energy to run the electric motors in the United States than it does to operate all the automobiles in the country. He said he also found that much of the energy used to run the electric motors is wasted during the conversion process from electricity to power.

"The motor was a good invention but I felt it could be improved," said Wanlass, who holds about 40 patents on electronic and computer components.

He said he called together his wife, Doreen, and their six children and told them of his plan to improve the electric motor. "I told them it would take some sacrifices and if I failed we'd have to start all over. They said go ahead," he said.

Since he left Philco and began working on his motor idea Wanlass said he has had to sell off the stock he got when his company was sold, take a second mortgage on his five-bedroom house and borrow money from friends. "I put up a little of the patent on the idea as collateral and I guess they believed in me," he said.

Wanlass said he took some of the basic physics equations on which the electric induction motor is based and began reworking them in his head. Sometimes, he said, he would lie down on the blue-and-gray couch in his study and stare at the ceiling for six or more hours, day after day, thinking about motors.

"People think you sit down with a calculator an just run through the equations and come up with something," he said. "It doesn't work like that. It's almost a creative process, like art or music. It involves long periods of deep thinking."

Sometimes, he said, he would take long walks in the darkness or drive his BMW to the beach near his home and sit staring for hours at the ocean.

Wanlass described his work habits with some discomfort during an interview last week and took pains to point out that he is not the stereo-type of the eccentric inventor or absent-minded professor.

"You have a feeling that something's there," he said. "There is a lot of very intense work that goes on in your head and you stop paying attention to other things. Then all of a sudden you say, 'Yes I think I can do it.' Then you go to a lab and begin working out the math. But the math comes second to coming up with the idea."

Experts who have examined Wanlass' motor design say it is extremely complex and involves an alternation of some basic design concepts. "It's like building a new milk bottle," said an electrical engineer for a California utility last week. "I wish I'd thought of it."

Like many complex physics concepts, experts say, the best way to explain new engine design is in mathematical equations rather than in words.

However, according to Wanlass a reasonable approximation in layman's term of how the new engine works goes like this:

The point of any electric motor is to take electric power and cause it to magnetize metal surrounding the motor's core. This magnetic force causes the drive shaft at the motor's core, which is called a rotor, to spin and do work.

The problem with any electric motor is that there are two ways to lose efficiency: first, by the wasting of the electricity by turning it into heat as it passes through the wire inside the motors, and second, by the wasting of the magnetic force.

The Wanlass motor addresses itself to two ways in which the magnetic force is wasted.

First, in a conventional electric motor there is no way to regulate how much metal is magnetized. Despite the fact that a conventional electric motor there is no way to regulate how much metal is magnetized. Despite the fact that a conventional electirc motor might only need to do 10 per cent of the work it is capable of, 100 per cent of the metal doing the pulling on the rotor is magnetized.

It would be much more efficient to only magnetize enough metal to pull the rotor, and that is what the Wanlass motor does. This is accomplished by the way electric coils are wound around the metal to be magnetized. The actual configuration of the winding is kept secret by Wanlass.

Second, the Wanless motor addresses the fact that any electric motor causes back forces to be built up inside the motor. This force is called a backEMF (electromotive force.)

In a conventional motor, the back-EMF spends its time fighting the incoming current through a single set of windings. The Wanlass motor adds a second set of windings and a capacitor that stores and regulates the flow of current.

In the Wanlass motor the amount of copper wire in the second winding is much different than the amount in the first winding.

Both sets of windings, in conjunction with the capacitor, produce two different magnetic fields that complement each other rather than cause the competition between the incoming current and the back-EMF.

Essentially what happens is that in the second winding the current travels directly to the motor to do work, encountering little opposition from the back-EMF. That is because the back-EMF is greater in the first winding, where it is captured as useful energy.

This useful energy can then be shunted back into the second winding as current, thereby causing less electricity to be requried from the initial source.

This transfer of power from the first winding to the second also smooths out the flow of energy to the motor. This diminishing of turbulence increases the efficiency and lowers the heat loss.

Wanlass said his motor design approaches the limits of maximum energy efficiency.

He said he offered the design to a number of major motor manufacturers in the United States but with-drew the offer when the big manufacturers refused to pledge in writing to keep the details of his invention confidential.