A motor is a device powered by electrical energy (current) that causes the motor to spin creating torque. Found in a myriad of industries and applications, a motor can be powered by either alternating or direct current. A generator is an electric motor operating in reverse, converting mechanical power into electrical current.
General purpose industrial motors (both IEC and NEMA frames) have highly standardized dimensions and characteristics which allows easy substitution from brand to brand. Motors are classified according to output power (kW or HP), speed, input voltage, output design, internal design amongst others.