VARIABLE FREQUENCY DRIVE. VFDs are widely used in industrial applications for motor control, providing significant energy savings and precise motor operation.

Variable frequency drive .A Variable Frequency Drive (VFD) is an electronic device used to control the speed and torque of an electric motor by varying the frequency and voltage of its power supply. VFDs are widely used in industrial applications for motor control, providing significant energy savings and precise motor operation.

1. VARIABLE FREQUENCY DRIVES PREPARED BY NITIN TYAGI

2. CONTENTS 1. What is VFD? 2. Purpose Of VFD 3. VFD System 4. Drive Operation 5. Operating Modes 6. AC Induction motor 7. components 8. Advantages 9. Function & Features 10. Applications.

3. WHAT IS VFD? Variable Frequency Drives This technology has several different names such as : Variable speed drives. Adjustable speed drives. Adjustable frequency drives. Frequency converter.

4. THE PURPOSE OF VFD pump and fan applications. control and regulation. Speeding up or slowing down a machine or process . • Protection from overload currents • Safe Acceleration

5. A variable frequency drives used in a drive system consisting of the following three main sub-systems : AC Motor. Controller . Operator Interface.

6. OPERATING MODES In variable-speed applications, a dc motor may be operating in one or more modes: – Motoring. – regenerative braking. – dynamic braking. – Plugging. – four quadrants.

7. AC INDUCTION MOTOR THEORY Torque is produced as the induction motor generates flux in its rotating field. • This flux must remain constant to produce full-load torque.

8. AC INDUCTION MOTOR THEORY The speed of the rotating electric field within the induction motor. Synchronous Speed = 120 x frequency/no . of motor poles

9. 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 wavediode bridge . • The DC bus is the true link between the converter and inverter sections of the drive

10. COMPONENTS OF VFD Vacuum tubes. Thyristors (SCR’s). Transistors .

11. ADVANTAGES Control of process temperature and pressure. Maintenance costs can be lower. Save energy. Limit the torque

12. FUNCTIONS & FEATURES Set-up Parameters The Control Method Acceleration or Accel -Ramp Rate Automatic Restart Stopping Method Automatic Signals

13. APPLICATIONS Water Supply Pump Application Conveyor Application Exhaust Fan Application Compressor Application

14. CONCLUSION Significant energy savings Easy setup & programming Better design Competitive edge