What Electric Drive Is
Modern electric drive consists of electric motor, power electronic converter and automatic control system. With the help of electric motors almost all the mechanisms in the factories, vehicles and household appliances are driven. Trams and trolley buses, trains and airplanes, machinery and cranes, ships and cars, fans and air conditioners, washing machines and refrigerators, printers, watches, scanners, disk drives are equipped with electric drives. A variety of drives (from small one which drives a clock, to a giant of two-story building size that drives a powerful rolling mill) together consume more than 60% of energy produced by all power stations in Ukraine. Modern automated production is impossible without electric drives.
The structure of modern electric drive of industrial mechanism
Power network is a source of electrical energy.
Power converter is used to control the flow of electrical energy coming from power network to the motor. Electric power control made by converter allows you to control the speed of the motor. Modern converters are made on the basis of high-power semiconductor devices.
An automatic control system is a part of a converter and represents a microprocessor control system specially programmed to stabilize the motor speed.
A motor is a device that converts electrical energy into mechanical energy. Besides the classic rotational motors there are linear motors. Movable part of linear motors moves linearly.
The reduction gear is applied to change the mechanical energy parameters (e.g. for reducing speed and increasing torque or for converting rotational motion into linear).
An actuator is a mechanism that performs useful work directly (lifts a cargo, moves a vehicle, rotates a fan, etc.).
Process Automation System is a computerized device that directs the operation of the actuator. Control is performed by calculation of the speed signal. This signal is used in control system of electric power converter.
Fields of usage of electric drive