Answered Questions

  • Over Exited Alternator

    When alternator is over exited, the power factor will be a. Lagging b. Leading c. Zero

    Dipti Ranjan

    • Mar 7th, 2016

    Pf is lagging because A.R is demagnetizing.

  • Half Controlled and Full Controlled Rectifier

    What is the difference between half controlled and full controlled rectifier? Why we go for full controlled while half controlled can control voltage?

    k.r.kartheeswari

    • Apr 10th, 2017

    In Half controlled rectifiers, the controlled output will be in one half cycle, so the efficiency is less. But in full controlled rectifies, the controlled output will be in both the half cycle since both the sides having SCRs. So efficiency also doubled compared to half controlled.

  • AIR GAP

    What is the role of air gap in any electrical machine how does it affects induce emf??

    A.Rajasekharreddy

    • Sep 13th, 2016

    Air gap is used to produce magnetic flux between stator and rotor. Air gap is more uniform for the production of sinusoidal EMF in alternators to eliminate the harmonics. Air gap is more in syn machin...

    NITIN

    • Aug 10th, 2016

    Airgap is used to produce magnetic field between stator and rotor. Flux is produce in rotor winding, then torque develop and rotor is rotating, but if air gap is more between stator and rotor then more magnetizing current is required and also loss is more.

  • How does a generator generate reactive power

    Does it absorb reactive power when ever it is needed ?

    Scott Munnings

    • Sep 17th, 2018

    A machine is run overexcited when VARs are needed by the house load or the grid. Running overexcited up to the machines rating is not necessarily a bad thing. VARs needed to magnetize other machines...

    Scott Munnings

    • Sep 17th, 2018

    Yes. It is measured for both metering (billing) and protective relaying purposes.