Discussion in 'The Projects Forum' started by b.shahvir, Jan 9, 2009.

  1. b.shahvir

    Thread Starter Active Member

    Jan 6, 2009
    Hi Guys, :)

    My query is a bit abstract in nature! But i will be very grateful if someone can provide me with the solution to my query. Here goes;

    Consider two Permanent Magnet (PM) Alternators Alt 'A' & Alt 'B' connected in parallel, supplying equal power to a purely 'Resistive' load (unity p.f.). Both the Alternators have equal stator synchronous reactances (stator resistances can be neglected). Please note, they are not connected to the local power grid (infinite bus). Now, if i increase the driving torque of say, Alt 'A', then what changes will occur with respect to the following electrial parameters:-

    1) Will magnitude of induced emf 'Ea' of Alt 'A' increase/decrease ? Please explain.

    2) Will magnitude of induced emf 'Eb' of Alt 'B' increase/decrease ? Please explain

    3) Will magnitude of terminal voltage 'Vt' increase/decrease ? If the magnitude of 'Vt' remains constant or decreases (due to armature reaction), then please explain.

    4) Can someone please provide me with a practical phasor diagram for the above query. I am asking for one, since the phasor diagrams in textbooks have lot of assumed conditions & hence do not relate to practical conditions!
    Any kind of help will be highly appreciated.

    For additional information/discussions please email me at

    Thanks & Regards,