Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Air gap flux density in DC machine

  1. Dec 15, 2012 #1
    Why is it that the air gap flux density is flat topped at no load. What happens to it's shape when machine is loaded?
     
  2. jcsd
  3. Dec 16, 2012 #2

    jim hardy

    User Avatar
    Science Advisor
    Gold Member

    Is flux = mmf/reluctance? Is air gap constant under pole piece?


    Have you looked up "Armature Reaction" ?

    Unloaded, the only MMF is that from the field current. When armature current begins to flow, armature mmf changes shape flux .

    Surely your textbook shows diagrams...
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook