Please help

Discussion in 'Homework Help' started by axeman, Jul 10, 2007.

  1. axeman

    Thread Starter New Member

    Jul 10, 2007
    Hi, I am doing some studying but I'm very stuck.

    My question is, I have a 30W, 200V, 800rpm dc motor connected to a 230V single phase, 50HZ line using a bridge converter. The full load armature current is 150A and the armature resistance is 0.06 Ohms.

    I have worked out the firing angle under rated full load like this:


    So Vd/(0.9*VRMS) = 200/(0.9*230) = .96 ArcTan = 15 degrees.

    The thing I'm stuck on is hoe to calculate the firing angle required so that the motor developes its rated torque at 400rpm.

    Please could anyone help?