The AC drive industry is growing rapidly and it is now more important than ever for technicians and maintenance personnel to keep AC drive installations running smoothly. AC drives change the speed of ac motor by changing voltage and frequency of the power supplied to the ac motor. In order to maintain proper power factor and reduce excessive heating of the motor, the name plate volts/hertz ratio must be maintained. This is the main task of VFD. AC drives basic working principle:

  1. AC drives are used to stepless speed control of squirrel cage induction motors mostly used in process plants due to its ruggedness and maintenance free long life.
  2. AC drive control speed of ac motor by varying output voltage and frequency through sophisticated microprocessor controlled electronics device.
  3. AC drive consists of Rectifier and inverter units. Rectifier converts AC in DC voltage and inverter converts DC voltage back in AC voltage.