Interview Question – Variable frequency drives

Briefly explain the VFD commissioning procedure.

What are harmonics?

Harmonics are integer multiples of the fundamental frequency of voltage or current present in the system. Read More: Harmonics Made Simple!

What are the harmonics mitigation techniques?

Harmonics can be mitigated by adopting any one of the following techniques:

  • Inductive reactors
  • 12-pulse or 18-pulse converters
  • Passive filters
  • Active front end drives
  • Active harmonic correction filters

What are the advantages of VFD?

  1. Using variable frequency drives, it is possible to control the motor speed as required.
  2. Can save a lot of energy.
  3. No inrush current as in the case of DOL or Star Delta Starters.
  4. VFD has many build in protective functions that helps improve the life of the motor.

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