VFD The Energy Saver

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VFD / VSD (Variable Frequency Drive or Speed Drive)

Introduction :

  • VFD are used to control motor speed to get the desired output .
  • Motors running at constant speed generate full flow of air , but to reduce the flow we are using dampers , we are using full energy of motor and using low output air flow this causes waste of energy , so we use Vfd for air flow control .
  • VFD are alternate for dampers , valves , etc 
  • Energy Savings by using VFD is (30- 70 % )  .

Applications :
Pumps, Fans, Compressors, Elevators , Cranes , HVAC systems, conveyors
Advantages : 
Smooth & Controlled Start Stop .
Minimize Inrush Currents .
Regulate Speed or Torque 
Energy saving ( power Consumption is less).


VFD Parts :
Rectifier, DC chokes , Snubber Capacitor , IGBT .
Working :
When a 3 phase Ac supply given to VFD is Rectified by SCR to Pulsating dc ,
Ripples in dc is reduced using filters ( choke + capacitor ) ,
Pure dc obtained after filtering Dc supply feed to IGBT for inverter .
Variable Voltage & Variable Frequency Obtained is fed through a motor .
V/f ratio remains constant for motor maintaining Constant torque & speed.
Disadvantage :
Produces Harmonics .







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