Question

(360) Volt, 60 Hz, 600 hp, 0.6 pf-leading, four-pole -connected synchronous motor has 0.9Ω synchronous reactance. Friction; wind; core losses and armature resistance are neglected.

a) If the motor is operating under magnitude of phase current (ia) (180)

Ampere and power factor of 0.6 lagging,

1. Find the input power of motor in hp

2. Find the generated voltage, EA

3. Find the torque and the maximum inducible torque in current state.

b) If EA is increased by 18% find,

1. Magnitude of new armature current (ia),

2. New power factor of motor.

Answer #1

410 Volt, 60 Hz, 600 hp, 0.6 pf-leading, four-pole Triangle
connected synchronous motor has 0.9Ω synchronous reactance.
Friction; wind; core losses and armature resistance are
neglected.
a) If the motor is operating under magnitude of phase current
(ia) 230 Ampere and power factor of 0.6 lagging,
1. Find the input power of motor in hp (10p)
2. Find the generated voltage, EA (10p)
3. Find the torque and the maximum inducible torque in current
state. (10p)
b) If EA is...

The 400 V, 50 kVA, 0.8 power factor leading delta connected
synchronous motor has synchronous reactance of 3-ohm, resistance
neglected. It is supplying a 12-kW load with initial power factor
of 0.86 lagging. The windage and friction losses are 2.0 kW and the
core losses are 1.5 kW. Determine
(a) the motor efficiency; the line current; armature current;
and excitation voltage.
(b) If the flux of the motor is increased by 20 percent
determine the excitation voltage; armature current; and...

a 460-V 100-hp 60-Hz 4 pole Y connected synchronous motor has a
operating power factor 0.85 leading the aramature resistance is o.2
ohms and synchronous reactance is 12 ohms at full load the
efficiency is 85% find the sum of mechanical loss core loss and
stray loss when meachine is operating at full load

A 75-kW, 440-V, 0.8-PF-leading Y-connected synchronous generator
has an armature resistance of 0.22 Ω and a synchronous reactance of
3.0 Ω. Its efficiency at full load is 89% (1 Hp=746 watt).
(a) What is the line current of the generator at rated
conditions?
(b) What is the internal generated voltage EA of this motor at
rated conditions?

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 3-phase, 1.2 MVA, Y-connected, 6.6 KV, 6-poles, 60 HZ,
synchronous generator has a synchronous reactance of 30W and
negligible resistance. The generator is connected to an infinite
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
current (Ia), the power factor and the reactive power...

Question
A 208 V 10 Hp four pole 60 Hz Y connected induction motor has a
full load slip of 5%.
a)-What is the synchronous speed of this motor?
b)-What is the shaft speed of this motor at full load?
c)-What is the frequency of rotor current at full load?
d)-What is the shaft torque of this motor at full load?
e)-If the efficiency of this motor is 90% at full load what is
the input power
f)-If the efficiency...

A three-phase, 9,375 kVA, 13.8 kV, 4-pole, 60 Hz, Y-connected
synchronous generator has a synchronous reactance, Xs = 17.9, and
is connected to an infinite bus at rated voltage. If the rotational
and electrical losses are negligivle, what is Ia, Ef, delta, theta,
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
If is adjusted so that the machine delivers rated kVA, 0.8 pf
lagging,...

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 synchronous generator 480-V, 50-Hz, Y-connected, six-pole has
a power rating of 50 kVA at pf 0.8 lagging. The synchronous
Reactance Generator is 1.0 Ω per-phase. This Generator is connected
to the 45 kW steam turbine. The friction loss and the core
generators are respectively 1.5 kW and 1.0 kW.
Question : Draw a Capability curves!

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