Assignment No. 1
Course : AC Machines | Course Code: EE 2223 |
Instructor: Prof. Riaz Ahmad Rana | Sections: F09 – A, D & G |
Assignment Date: March 15, 2011 | Submission Date: March 31, 2011 |
Question # 1
A 3-phase, 2000KVA, 11 KV, star-connected alternator has armature resistance of 1 Ω/phase and a synchronous reactance of 10 Ω/phase. The speed and the excitation current remain unchanged.
Find the percentage change in terminal voltage when the rated output of 2000 KVA is switched on at :
(1) 0.8 PF Lagging Load?
(2) Unity PF Load?
(3) 0.8 PF Leading Load?
(4) EA from equivalent circuit?
Problem # 2
A 3-phase, 2300 V, 1000 KVA, 50 Hz, star connected synchronous generator has the following parameters:
p.f.= 0.8 Lagging, Poles = 2, Ra / phase = 0.15 Ω, Xs / phase = 1.1 Ω, PF&W = 24 KW, PCORE = 18 KW, VF = 200 V, IF = 10 A, R F = 20 – 200 Ω
a) Internal generated voltage of this generator at rated current?
b) Torque angle?
c) Generator’s prime mover output?
d) Generator efficiency?
e) % age Voltage Regulation?
f) Approximate power of generator?
g) Static Stability Limit?
h) Phasor Diagrams?
Problem # 3
A 3-phase, 2300 V, 1000 KVA, 50 Hz, star connected synchronous generator has the following parameters:
p.f.= 1, Poles = 2, Ra / phase = 0.15 Ω, Xs / phase = 1.1 Ω, PF&W = 24 KW, PCORE = 18 KW,
VF = 200 V, IF = 10 A, R F = 20 – 200 Ω
a) Internal generated voltage of this generator at rated current?
b) Torque angle?
c) Generator’s prime mover output?
d) Generator efficiency?
e) % age Voltage Regulation?
f) Approximate power of generator?
g) Static Stability Limit?
h) Phasor Diagrams?
Problem # 4
A 3-phase, 2300 V, 1000 KVA, 50 Hz, star connected synchronous generator has the following parameters:
p.f.= 0.8 Leading, Poles = 2, Ra / phase = 0.15 Ω, Xs / phase = 1.1 Ω, PF&W = 24 KW, PCORE = 18 KW, VF = 200 V, IF = 10 A, R F = 20...