Substrate Record: qid 11926

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qid 11926 · engineering

Question: A six-pole, 30-slot dccommutatorgenerator has alapwound armature winding. The armature constant, K_a is 9.55. The generator is operated with a separately excited field such that the field flux per pole is 0.04weber/pole. The generator is driven at a speed of 3000 rpm. The no load armature voltage is 418.9 V. The above generator is now operated as a motor. The flux is 0.04weber/pole. It is desired to supply a load requiring a torque of 50 n-m at 4000 rpm. Armature circuit resistance is 0.075 ohm. Calculate (a) the backemf, (b) the required armature current and voltage to supply this load.

1. Backemf: 155 V, Armature Current: 115.9 A, Armature Voltage: 154.8 V
2. Backemf: 140 V, Armature Current: 160.9 A, Armature Voltage: 139.8 V
3. Backemf: 170 V, Armature Current: 110.9 A, Armature Voltage: 179.8 V
4. Backemf: 160 V, Armature Current: 130.9 A, Armature Voltage: 169.8 V
5. Backemf: 150 V, Armature Current: 120.9 A, Armature Voltage: 159.8 V
6. Backemf: 200 V, Armature Current: 100.9 A, Armature Voltage: 199.8 V
7. Backemf: 190 V, Armature Current: 150.9 A, Armature Voltage: 189.8 V
8. Backemf: 175 V, Armature Current: 125.9 A, Armature Voltage: 174.8 V
9. Backemf: 180 V, Armature Current: 140.9 A, Armature Voltage: 179.8 V
10. Backemf: 165 V, Armature Current: 135.9 A, Armature Voltage: 164.8 V

Our answer: D. Backemf: 160 V, Armature Current: 130.9 A, Armature Voltage: 169.8 V Source quote machine-checked (exact quote)

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