- Hi I Need Help With This Asap Thank You Very Much 1 (200.44 KiB) Viewed 32 times
hi! i need help with this asap..thank you very much!
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answerhappygod
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hi! i need help with this asap..thank you very much!
hi! i need help with this asap..thank you very much!
(b) A dc shunt motor has an armature winding resistance of 0.8 12. The armature terminals are connected to a dc supply of 500 V and the motor is running at a speed of 1500 rpm when the armature current is 85 A. (i) Determine the torque developed. (ii) If the field flux is reduced by 10 % due to the addition of a resistance in series with the field windings, determine the armature current and the speed of the motor. Assume that the torque developed is the same as in part (i). (8 Marks) (c) The armature winding resistance of a separately-excited dc generator is 0.4 12. The field circuit is connected to a 120 V dc supply. Rotational losses of the machine are 100 W. The generator is driven at a speed of 1200 rpm by an external prime mover and the no-load terminal voltage is 120 V for a field current of 0.5 A. A load resistance of 422 is connected across the armature terminals. The effects of armature reaction can be neglected. (i) Determine the output power of the generator with the external prime mover running at a speed of 1200 rpm and the field current is 0.5 A. (ii) The speed of the external prime mover is now decreased to 1000 rpm with the field current remaining at 0.5 A. Determine the efficiency of the generator. (9 Marks)
(b) A dc shunt motor has an armature winding resistance of 0.8 12. The armature terminals are connected to a dc supply of 500 V and the motor is running at a speed of 1500 rpm when the armature current is 85 A. (i) Determine the torque developed. (ii) If the field flux is reduced by 10 % due to the addition of a resistance in series with the field windings, determine the armature current and the speed of the motor. Assume that the torque developed is the same as in part (i). (8 Marks) (c) The armature winding resistance of a separately-excited dc generator is 0.4 12. The field circuit is connected to a 120 V dc supply. Rotational losses of the machine are 100 W. The generator is driven at a speed of 1200 rpm by an external prime mover and the no-load terminal voltage is 120 V for a field current of 0.5 A. A load resistance of 422 is connected across the armature terminals. The effects of armature reaction can be neglected. (i) Determine the output power of the generator with the external prime mover running at a speed of 1200 rpm and the field current is 0.5 A. (ii) The speed of the external prime mover is now decreased to 1000 rpm with the field current remaining at 0.5 A. Determine the efficiency of the generator. (9 Marks)
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