motor

A motor is a machine that converts energy into mechanical power, providing torque and motion. Motors can produce rotational or linear movement and are used in countless applications, from household appliances to industrial machinery. They are powered by various energy sources, including electricity, combustion of fuel, or pressurized fluids.

Electric motors are the most common type. They convert electrical energy into mechanical energy and include alternating-current (AC) and direct-current (DC) types. AC motors include induction and synchronous motors; DC motors include brushed and brushless variants. Modern control often uses variable frequency drives or pulse-width modulation to adjust speed and torque.

Internal combustion engines (often simply engines) convert chemical energy to mechanical energy through combustion. They power most road vehicles and many generators. Engines differ by ignition method: spark-ignition (gasoline) and compression-ignition (diesel). They balance factors such as efficiency, emissions, and power-to-weight characteristics.

Other motor types include hydraulic motors, which convert fluid power into rotation; pneumatic motors driven by compressed air; and precision devices such as stepper and servo motors that provide accurate positioning and control.

Key performance measures for motors include torque, speed (rpm), output power, efficiency, and power density. Design choices affect starting torque, control complexity, cooling, lubrication, and reliability. Safety standards address electrical isolation, guarding, and noise.