Electrical World

Electrical Question 1: Explain Armature reaction in DC machine ? Answer: Armature reaction is the effect of the magnetic field set up by the armature current on the distribution of the flux under the main poles of the DC machine. Emf will be induced in the armature of the dc machine by the Fleming's electromagnetic induction principle (Conductor and magnetic field required to produce emf). As the conductors of the armature are shorted current starts flowing and this current will produce a counter magnetic filed which opposes the main field. This effect of armature flux on the main flux so as to distort or weaken the main field flux is called armature reaction. Electrical Question 2: What is the effects of the armature reaction in a dc machine? Answer: Due the armature reaction the armature flux will have two impacts on the main field flux It partly weakens or distorts the main field flux It cross magnetises or distorts the main field flux Elect...