I read it probably 15-20 years ago, but it's probably older. I remember the inventor wanting to just release it to the world to give everyone free unlimited energy, but fearing government and corporate reprisals, so instead he puts the engine in a washing machine and sells that. Sound familiar?
Looking for a science fiction short story
"The Man Who Learned Loving" aka "Brownshoes", a short story by Theodore Sturgeon, also the (unaccepted) answer to this old question and this one; first published in Adam, May 1969; reprinted in The Magazine of Fantasy and Science Fiction, October 1969, which is available at the Internet Archive. Does any of these covers ring a bell?
about an inventor who creates a perpetual energy motor
Also he knew about transistors and double-helical gears and eccentric linkages and things like Wankels and fuel-cells. He fiddled around a lot in the back room with magnets and axles and colored fluids of various kinds, and one day he had an idea and began fooling with scissors and cardboard and some metal parts. It was mostly frame and a rotor, but it was made of certain things in a certain way. When he put it together the rotor began to spin, and he suddenly understood it. He made a very slight adjustment and the rotor, which was mostly cardboard, uttered a shrill rising sound and spun so fast that the axle, a ten-penny nail, chewed right through the cardboard bearings and the rotor took off and flew across the room, showering little unglued metal bits.
I remember the inventor wanting to just release it to the world to give everyone free unlimited energy, but fearing government and corporate reprisals,
He also thought of making blueprints and scattering millions of copies over cities all over the world, and of finding good ethical scientists and engineers and banding them together into a firm which would manufacture and license the device and use it only for good things. Well you can do that with a new kind of rat-killer or sewing machine, but not with something so potent that it will change the face of the earth, eliminate hunger, smog, and the rape of raw materials — not when it will also eliminate the petro-chemical industry (except for dyes and plastics), the electric power companies, the internal combustion engine and everything involved in making it and fueling it, and even atomic energy for most of its purposes.
so instead he puts the engine in a washing machine and sells that.
Not a washing machine:
When it was time he redesigned his device, not with cardboard and glue, but with machined parts that were 70% monkey-puzzle — mechanical motions that cancelled each other, and wiring which energized coils which shorted themselves out. He patented parts and certain groupings of parts, and finally the whole contraption. He then took his degrees and graduate degrees, his published scholarly papers, his patents and his short hair-cut, together with a letter of introduction from his pastor, to a bank, and borrowed enough to buy into a failing company which made portable conveyor belts. His device was built into the drive segment, and he went on the road to sell the thing. It sold very well. It should. A six-volt automobile battery would load coal with that thing for a year without needing replacement or recharging, and no wonder, because the loading was being powered by that little black lump in the drive segment, which, though no bigger than a breadbox, and requiring no fuel, would silently and powerfully spin a shaft until the bearings wore out.