By Andrea Becker
Updated Mar 24, 2022
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Almost inevitably, you’ll encounter a toy that no longer moves or a small child’s frustration with a broken gadget. While you might fix the toy, the real question is how a coil of wire turns electrical energy into motion. Electric motors are the hidden workhorses behind everyday devices—from cars and clocks to computer cooling fans.
The heart of a motor is the rotor, a cylindrical armature that spins. Surrounding it is the stator, which contains insulated copper windings. When current flows through the stator, it creates a magnetic field that pulls the rotor into rotation. In many designs, small brushes or conductive fibers maintain electrical contact as the rotor turns.
Electricity flowing through a conductor generates a magnetic field. When the stator’s field meets the rotor’s field, magnetic attraction and repulsion produce torque— the rotational force that spins the motor. In DC motors, the direction of current is reversed by the motor’s internal electronics, while AC motors rely on electromagnetic induction to drive the rotor.
DC motors, powered by batteries, are common in handheld tools and small appliances. AC motors, which run on household mains, use two non‑contact windings to create a rotating field—making them brushless and highly efficient. Brushless DC motors also switch polarity to keep the rotor turning, while universal motors can operate on either AC or DC power.
With a few household items you can build a simple motor: wrap a coil of lower‑gauge copper wire, suspend it through the center of an aluminum can, and place strong magnets on either side. Connect the coil to a battery with alligator clips; the coil will become an electromagnet and begin to spin, illustrating the principles of motor operation.
