Questions about DC Machines

Replies

• 

  AMITBOSE

  Re: dc machines
  
  U can refer ashfaq hussain book
• 

  vishnu priya

  Re: dc machines
  
  

  AMITBOSE

  U can refer ashfaq hussain book

  More details please!!!
• 

  Mr.Don

  Increase in flux decreases the speed but increases the torque. If torque is decreased by decreasing the field current the following sequences are found:
  
  

  1. Counter Electromotive Force drops instantly, the speed remaining constant because of the inertia of heavy armature.
  2. Due to decrease of EMF armature current I is increased because of I = (V − E)/R.
  3. A small decrease of flux is more than counterbalanced by a large increase of I which means net increase of torque.
  4. If torque increases the speed also increases.

  If applied voltage is kept constant, motor speed has inverse relation with flux.
  where:
  
  

  • N = revolutions per minute .i.e. motor speed
  • K = proportional constant
  • R = resistance of armature (Ohm)
  • V = electromotive force (Volt)
  • I = current (Ampere)
  • Φ = flux (Weber %28Unit%29)
• 

  Mr.Don

  You will know it clearly by doing lab exercises perfectly..
• 

  ashutoshglamour

  You can find the answers in book-B.L.THEREJA
• 

  cowboy

  I can find answer in any electrical machine book like b.L.Thareja volume 2.