1. Whatis VFD?2. Purpose Of VFD3. VFD System4. Drive Operation5. Operating Modes6. AC Induction motor7. components8. Advantages9. Function & Features10. Applications.
Variable Frequency DrivesThis technology has several different names suchas :• Variable speed drives.• Adjustable speed drives.• Adjustable frequency drives.• Frequency converter.
• pump and fan applications.• control and regulation.• Speeding up or slowing down a machine or process.• Protection from overload currents• Safe Acceleration
A variable frequency drives used in a drivesystem consisting of the following three mainsub-systems:• AC Motor.• Controller.• Operator Interface.
• In variable-speed applications, a dc motor may be operating in one or more modes: – Motoring. – regenerative braking. – dynamic braking. – Plugging. – four quadrants.
• Torque is produced as the induction motor generates flux in its rotating field.• This flux must remain constant to produce full-load torque.
The speed of the rotating electric field withinthe induction motor.Synchronous Speed = 120 x frequency no. of motor poles
• All VFD’s need a power section that converts AC power into DC power.• This is called the converter bridge.• Sometimes the front end of the VFD, the converter is commonly a three-phase, full wave- diode bridge.• The DC bus is the true link between the converter and inverter sections of the drive