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Homework Help: I'm confused with the output torque, torque developed in the armature

  1. Sep 21, 2008 #1
    1. The problem statement, all variables and given/known data
    The armature winding of a 200 volt, 4-pole series motor is lap connected. There are 280 slots and each slot has 4 conductors. The current is 4 amperes and the flux per pole is 18 mWb. The field resistance 0.3 ohm and the armature resistance is 0.5 ohm. The iron and friction losses amount to 800 watts. Find: a. Output torque, b.) torque developed in the armature. and c) the lost torque

    2. Relevant equations

    3. The attempt at a solution
    This is my attempt.
    since it is lap= the number of parallel paths is 4
    and the number of conductors= 280 * 4= 1120 conductors

    Ec=200-4(.5+.3)= 196.8 v
    N= 585.71


    Pin @full load= (200)(4)=800
    Pfield= (4^2)(.3)=4.8

    Pout= -12.8 w (There is no negative power right?)

    Tout=-0.2087 Nm
    Tlost=13.04 Nm

    so... am i stupid or what
  2. jcsd
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