Question

The line current of a three-phase engine in delta configuration
is 25 A, connected to a supply network with a line voltage of 240 V
and absorbing a power of 15 kW. The efficiency of the engine is
90%.

Taking as a reference of line voltages V1= V∠0º, and a direct
sequence, find:

a) The phasors of the line voltages

b) The phasors of the line and phase currents

c) The reactive and apparent power

d) The mechanical power (at the engine's axis)

e) The equivalent single phase circuit formed by a single
impedance

Answer #1

A delta connected balanced load with impedance "20 - j15" is
connected to a star connected generator in positive sequence with
Van = "107.43 - j312". Calculate phase and line currents and
voltages, also draw the configuration described with the voltage
and current labels.

A balanced ?-connected load has an impedance of 60+ j45 ? per
phase. The load is fed through a line having an impedance of 0.8+
j0.6 ? per line. The phase voltage at the terminals of the load is
???????? = 480 ?? . The sequence is positive. Use AB v as the
reference at the load. The source is required to be calculated for
either Wye or Delta connection. a) Draw the 3-phase system b) Draw
the a-phase equivalent...

A Wye-Delta transformer is connected to a 66 kV input
three-phase transmission line. Each transformer is rated at 1000
kVA and has a step-down ratio of 8:1. The bank supplies a balance
load having a power factor of 0.8 lag with a load current of 70 A.
Assume ideal transformer, determine.
The primary line and phase voltages
The secondary line and phase voltages
The secondary line and phase currents
The apparent and active power at the load
Total kVA capacity...

Please be clear in conceot and handwriting, thank
you.
A 20 kVA three-phase synchronous machine is connected to a 480
V, 60 Hz electrical service.
The per-phase armature reactance is 80%. Armature resistance is
negligible, as are all other sources of power loss.
Part A: Motor Configuration
The machine is configured to run as a motor. Its rated mechanical
power is 20 HP and it is 94% efficient.
The motor provides rated output mechanical power.
The excitation is set such...

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
that a voltage regulator has automatically adjusted the field
current so that the terminal voltage is its rated value. Mechanical
losses are...

Three single phase transformers having a 15:1 ratio are
wye-connected to a 2400 V three phase line as a step-down
transformer. What is the line voltage of each transformer? What is
the secondary voltage of each transformer if they are delta
connected to the same line?

A wye connected three-phase source is delivering a line voltage
of 480 V at a line current of 25 amperes.
Find
a) the phase voltage
b) the phase current
c) the line voltage
d) the line current
e) the total power delivered.

The magnitude of the phase voltage of an ideal balanced
three-phase Y-connected source is 110 V . The source is connected
to a balanced Y-connected load by a distribution line that has an
impedance of 0.1+0.8i Ω/ϕ . The load impedance is 20.2+14.8i Ω/ϕ .
The phase sequence of the source is acb. Use the a-phase voltage of
the source as the reference.
Part A: Specify the magnitude and phase angle of the line
current IaA.
Part B: Specify the...

A balanced wye-connected three-phase source has line-to-neutral
voltages of 400 V rms.
- Find the rms line-to-line voltage magnitude.
- If this source is applied to a wye-connected load composed of
three 33 Ω resistances, find the rms line-current magnitude.
- If this source is applied to a wye-connected load composed of
three 33 Ω resistances, find the total power delivered.

A 100 MVA, 13.2 kV three phase generator (G) having a
synchronous reactance of 10% is connected to a three phase Y-Y
transformer T1 which feeds a 132 kV 10 miles transmission line
having an impedance per phase of 2 + j5 ?/mile. At the receiving
end of the transmission line is a Y-Y step down transformer T2.
Three loads are connected to the secondary side of the transformer
T2. Loads are as follows:
Load#1 40 MVA at 0.8 pf...

ADVERTISEMENT

Get Answers For Free

Most questions answered within 1 hours.

ADVERTISEMENT

asked 7 minutes ago

asked 7 minutes ago

asked 21 minutes ago

asked 25 minutes ago

asked 27 minutes ago

asked 30 minutes ago

asked 30 minutes ago

asked 30 minutes ago

asked 30 minutes ago

asked 31 minutes ago

asked 47 minutes ago

asked 56 minutes ago