Motor
An electric motor converts electrical energy into mechanical motion. Brushed and brushless motors, steppers and servo systems use different construction and control methods. Noise, efficiency and positioning performance depend on the actual motor, drive and load.
Electric motors convert electrical input into mechanical motion through magnetic forces. In a brushed DC motor, a mechanical commutator changes winding current as the rotor turns. A brushless motor instead needs electronic commutation. The windings, magnets and control method depend on the motor type.
In plain terms
An electromagnetic dance: stationary magnets and moving coils take turns shoving each other around a circle.
Why designers use it
- Drive wheels, fans, and pumps.
- Position a robot arm or 3D-printer head.
- Provide haptic feedback in phones and game controllers.
- Spin disks, optical drives, and reels.
Best for
- Locomotion
- Precision positioning
- Pumping and cooling
- Haptics
When not to use it
- Where a solenoid's quick linear motion would do.
- Where vibration or noise budget is tight and a brushless option isn't an option.
Common mistakes
- Driving a motor directly from a microcontroller pin — they need a driver.
- Forgetting flyback diodes on brushed-motor drivers.
- Underestimating stall current.
Where you will find it
- Quadcopter drones stay airborne because four brushless DC motors each spin a propeller at independently controlled speeds — the flight controller adjusts each motor 400 times a second to balance the craft.
- 3D printers use stepper motors to move the print head in precise micro-millimetre steps — the same physics is why CNC mills can carve metal to 0.01 mm and a film camera can pan smoothly.
- The vibration in your phone when a notification arrives is a tiny eccentric-mass DC motor spinning briefly — the same kind of mechanism, scaled up, drives an electric toothbrush head.
A short history
In 1831, Joseph Henry demonstrated an electromagnetic machine that rocked back and forth as its magnetic attraction and repulsion changed. It was an early demonstration of electricity producing controlled mechanical motion, not a modern continuously rotating motor. Motor development involved many designs and contributors rather than one universal invention story.
Good to know
- Brushless does not automatically mean Hall sensors. A controller can use position sensors or estimate rotor information electrically, for example from back-EMF.
- Henry's early electromagnetic machine rocked back and forth. Electrical motion came before the familiar motor shaft spinning continuously.