TwinFlywheel

This Idea was inspired by some annotations to another Idea (link).

The typical electric motor has two major interacting components, usually known as the "rotor", which rotates, and the "stator", which is stationary.

It is known that if the stator is mounted such that it is also allowed to rotate, then it will rotate in the direction opposite to the direction in which the rotor rotates. Both parts will simply rotate at half the normal rotation speed, relative to the stationary ground. Relative to each other, though, each part of the motor works as if the motor is rotating at "normal" speed.

So let us construct an electric motor with two "interactors" that are disk-shaped and basically very similar. The two disks have axial bearings, and are placed on the same (stationary!) axle, and are located with a quite-small gap between them. When electricity is applied, electromagnetic forces between the two disks cause them to rotate in opposite directions.

If the disks are identical, then we will want each disk to incorporate both electromagnets and permanent magnets, so that the overall device can act as either a motor or as a generator. The disks could instead be constructed so that all the electromagnets are in one disk and all the permanent magnets are in the other (reduces the need for "brushes" that carry electric power to a rotating object).

Now we can consider constructing this type of motor with two somewhat massive disks, such that when the motor is running at maximum speed, we have two energy-storing flywheels, which are rotating in opposite directions. A primary advantage of this design is that we don't need a separate motor/generator connected to the flywheel axle, as is typical for most energy-storing flywheel setups.

The secondary advantage, of course, is that two spinning disks lets us store twice as much energy as one (if, as pointed out in an annotation, the overall flat-disks electric motor runs at twice the normal speed, relative to each other).

And a third advantage, if the first annotations in the linked Idea are correct, is that this type of energy-storage flywheel will be more suitable for installing into vehicles, than ordinary flywheels that merely rotate in one direction, because certain gyroscopic effects will be reduced. (I have my doubts about the truth of that, but the first two advantages are sufficient, by themselves.)