Tukuk-OSThe shared secret is the interaction between current and magnetism: a wire carrying current in a magnetic field feels a force (the motor effect), and a wire moving through a magnetic field develops a voltage (Faraday’s induction, the generator effect). One machine, two directions of energy flow. A motor spins because current through a coil on an axle makes it a magnet that the housing magnets keep repelling and attracting — old designs flip the current every half turn with a mechanical commutator; modern ones do it electronically. A generator runs the causality backwards: turn the coil and the magnetic field pushes the electrons, forcing current out.
That reversibility is not trivia — it runs your world. Every grid supply is induction in a turbine hall (steam spun by gas, coal, nuclear, solar-thermal or falling water drags coils past magnets), and every regenerative brake is the same traction motor driven by the wheels instead of driving them, shoving current back into the battery while the car loses altitude or speed — hybrid and EV brake pads last years longer because the motor eats most of the work.
The efficiency story is where motors quietly beat combustion: well-built electric motors convert roughly ninety percent of electrical energy into motion, with the rest shed as heat and noise, while a petrol car manages 20–30% of the fuel’s chemical energy at the wheels, wasting the remainder through exhaust and radiator. It is why a small motor feels instant and a big engine feels hard work: one is a nearly-clean electron conveyor, the other is a heat engine forever fighting the limits of hot-to-cold conversion.