dc machine find speed??

Discussion in 'Homework Help' started by movafo, Apr 18, 2014.

  1. movafo

    Thread Starter New Member

    Apr 18, 2014
    I need to find the speed of a DC machine across a range of torque values I cant seem to find any formula anywhere that I can calculate speed with!?!

    I have the following DC machine values:
    armature r = 0.38ohms
    armature L = 5.8mH
    Field R = 57ohms
    field L = 9H
    Laf = 0.62
    moment of inertia = 0.16 Jkg m-2
    viscous friction B = 0.009Nms
    coulomb friction torque = Tf 6.6Nm

    these are the only values I have as well as a mechanical torque input variable, any help would be appreciated!
  2. MaxHeadRoom


    Jul 18, 2013
    The torque, and RPM for a given armature voltage is dependent on the field voltage.
    The higher the field current, the higher the torque, but lower rpm for a given voltage.
    You may have to find the results empirically.
    Last edited: Apr 18, 2014