Question

A three-phase Wye-connected synchronous generator is rated 3600
rpm, 200kVA, 480V, 60 Hz. The generator’s armature winding
resistance is R_{A} = 0.03Ω and the synchronous reactance
X_{S} is 0.25Ω. The rotational losses are 6kW, the core
losses are 4kW, and the stray losses are 1% of the output real
power. The generator is delivering 200kVA power at 0.85 pf lagging
at rated voltage. Taking the phase voltage at the output as a
reference, answer the following questions.

How many poles does this generator have?

2

4

6

10

8

20

The input power to the generator in kW.

Group of answer choices

170.00

181.70

176.43

186.88

195.21

189.16

Question 15

The input torque applied to the generator’s shaft (Nm).

386.9

495.7

443.6

522.5

374.6

299.9

Question 16

The percentage efficiency of the generator (neglect losses in the field winding) is

86.7

96.3

90.9

80.1

94.8

88.2

Answer #1

A 200kVA, 480v, 50Hz, star connected synchronous generator with
a rated field current of 5A was tested at rated speed and the
following data were taken:
1. The open circuit terminal voltage of the generator was 540v
at rated field current.
2. The short circuit line current was 300A at rated current.
3. With the machine at standstill, a dc voltage of 10v was
applied between two of the generator terminals, a current of 25A
was measured.
Determine the values...

Please be clear in concept and handwriting.
A 20HP, three-phase, Wye-connected synchronous motor is
connected to a 277VAC, 60Hz
power supply. At rated conditions, the motor runs at 3600 rpm and
presents a 0.85 lagging
power factor to the power supply. The per-phase armature reactance
is 350m?. Armature
resistance is negligible, as are all other sources of power
loss.
Considering rated conditions,
a. draw a single-phase equivalent circuit showing V?, Ea and IA,
with values.
b. draw a phasor diagram...

A 42 kVA three-phase synchronous generator with line voltage
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phase. Determine the voltage regulation when the power factor is
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A three-phase wye-connected (Y) synchronous generator is
operating at Ea = 8.OLO° kV (lineneutral) and has synchronous
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threephase delta-wye connected step-down transformer that is
constructed from three individual single-phase transformers. Each
the single-phase transformers has rated power of 200 kVA has a
turns ratio of 4:1 where the rated primary voltage of 8.0 kV and a
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A three-phase, 9,375 kVA, 13.8 kV, 4-pole, 60 Hz, Y-connected
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Tdrive, Phasor diagram, and power flow diagram (label completely
with numerical values for,
A) the machine as a generator; the prime-throttle is opened and
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A submarine has a 3-phase, Y-connected, 2- pole, 60Hz
synchronous generator rated to deliver 1687.5 kVA at a FP = 0.8
lagging with a line voltage of 450-V. The machine stator resistance
RS = 0.004 ?. The synchronous reactance is Xs=0.08 ?. The actual
system load on the machine draws 900 kW at FP = 0.6 lagging. Assume
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A 3-phase, 1.2 MVA, Y-connected, 6.6 KV, 6-poles, 60 HZ,
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bus at 6.6 KV and 60 Hz.
a)Determine the excitation voltage (Ea) when the machine is
delivering rated power at o.8 PF lagging.
b)The field excitation current is increased by 10% without
changing the power input from the prime mover. Find the stator
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There is a synchronous generator with a rated output of 100 MVA.
At rated output, voltage 6600v, power factor 85%, efficiency
98%.
Answer the questions below...
1- Voltage per phase for Y connection
2- Output current
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A three phase Y connected synchronous motor has negligible
armature resistance and a synchronous reactance of 12 ohm/phase.
The motor takes 12,000kW at a line voltage of 13,200V. If the line
current is adjusted so that the excitation voltage is
9000V/phase:
a. What is the torque angle?
b. At what power factor is the motor operating?
c. What is its armature current?

A 125 MVA 11 kV three phase 50 Hz synchronous generator has a
synchronous reactance of 1.33 p.u. The generator achieves rated
open circuit voltage at a field current of 325 A. The generator is
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kV and an equivalent impedance of 0.17 pu on the generator base.
The generator is loaded to a real power of 110 MW.
a- Find the generated voltage Eaf in p.u. such that the...

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