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Homework Help: Armature reaction and Lentz's law ?

  1. Jan 8, 2014 #1
    1) Is armature reaction seen in all machines ie DC, INDUCTION & SYNCHRONOUS machines ?
    (just answer briefly, which all machines exhibit it)

    2) Is back emf in DC motor nothing but LENZ'S law, or is the generating action in DC motor called the LENZ's law, or are both same, and I'm confused ? (plz clarify this briefly)

    3) Is magnetic drag in DC generator nothing but lenz's law, or is it motoring action in DC generator called the LENZ's law, or are both the same, and I'm just confused ?

    4) is armature reaction in dc motor nothing but lenz's law extension?

    5) is armature reaction in dc generator nothing but lenz's law extension ?
  2. jcsd
  3. Jan 8, 2014 #2


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    Gold Member

    Not an extension of Lenz's law, but a consequence.
  4. Jan 8, 2014 #3
    @maajdl, thanks mate. so 4) and 5) are consequences of AR.

    also it seems INDUCTION MACHINE, doesn't experience this AR, as they're homopolar, thus i guess only DC and synchrounous machines experience AR.

    But IMs, exhibit lenz's law, that's why they get torque developed in same direction as RMF, thus rotation, thus now how is lenz's law consequence.

    also in DC MOTOR, back emf = lenz's law = generating action, is this statement correct or contradictory.

    I'm really confused.
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