Give all your answers correct to 4 d.p. A 480 V permanent-magnet excited DC motor has armature resistance of 1.5 . When

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Give All Your Answers Correct To 4 D P A 480 V Permanent Magnet Excited Dc Motor Has Armature Resistance Of 1 5 When 1 (40.8 KiB) Viewed 34 times

Give all your answers correct to 4 d.p. A 480 V permanent-magnet excited DC motor has armature resistance of 1.5 . When driving a load of constant load torque at rated speed of 1,000 rpm, the armature takes rated 25 A. Speed is controlled by armature voltage variation, and armature is supplied from a three-phase fully controllable bridge rectifier. Available AC voltage is three-phase 400 V, 50 Hz, interfacing transformer is not used, and armature current is continuous a) The machine operates at rated speed with rated load. Determine rectifier output voltage and thyristor firing angle. [5 marks) Vrect Number V 0,= Number (degree) b) Determine the rated motor torque and power. [6 marks] Ten Number Nm P. = Number kW C) The machine operates at 25% of the rated speed with 60 % of the rated load. Determine rectifier output voltage and the thyristor firing angle. [5 marks) Vrect2 = Number v 02 Number • (degree) d) A three-phase rectifier can operate with different load types at the output. One possibility is placement of a capacitor across the output. Explain when this is done and why? (4 marks] (This question is manually graded.) A. - T. BIUS*, * Styles Font