Motors

A motor is a machine that converts energy into mechanical work, most commonly rotational motion. Motors are used to drive machines and devices across industries and consumer goods. The energy source may be electricity, compressed fluid, or chemical energy, depending on motor type. The opposite device is a generator, which converts mechanical energy into electrical energy.

Electric motors are the most common. They operate on electromagnetic principles, in which current in windings or permanent magnets interacts with magnetic fields to produce torque on a rotor. The stator provides a stationary magnetic field while the rotor turns. Variety exists: DC motors with direct current, including brushed and brushless designs, and AC motors such as induction (asynchronous) and synchronous motors. The universal motor can run on either AC or DC and is often used in portable appliances. Synchronous motors can provide constant speed and are often used in clock synchronization and HV equipment.

Other motor types include hydraulic motors that convert pressurized fluid energy into rotation, and pneumatic motors driven by compressed air. Internal combustion engines and turbine engines are sometimes described as motors, but in many engineering contexts they are labeled engines or prime movers; they convert chemical or thermal energy into mechanical energy rather than electricity.

Performance is described by power, torque, speed (rpm), and efficiency. Motors may be controlled by voltage, current, frequency, or electronic drives, such as variable frequency drives for AC motors or PWM controllers for DC motors. Mechanical systems, such as gears or belts, adjust speed and torque at the load. Proper design, cooling, and protection are important for reliability and safety.

Motors underpin a wide array of devices, from small household appliances to large industrial machines and transportation systems. Advances focus on efficiency, control accuracy, reliability, and integration with digital control systems.