Electrical drives

The main components of an electrical drive are electrical motor and load, power modulator, sources, control unit and sensing unit. The different motors used in electrical drives are dc motors (shunt, series, compound and permanent magnet), induction motors (squirrel cage and wound motor) and synchronous motors (wound field and permanent magnet). AC drives have more advantage than DC drives. Different power modulators in use are converters, inverters, ac voltage controllers, DC choppers and cycloconverters. For low power drives, single phase sources are used. For medium power drives, three phase sources (400 V) are used. For large motors, three phase sources (3.3 kV-11 kV) are used. Some drives are powered from batteries (24 V- 110 V). Control unit controls the power modulator. In semiconductor converters, control unit consists of linear and digital integrated circuits, microprocessors, transistors etc. Sensing unit consists of current sensors.