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WorksheetsSYNCHRONOUS GENERATORS QUIZ-1
Total questions: 20
Worksheet time: 21mins
possible number of slip rings for Rotating field and stationary armature type alternator.
2
4
1
3
A 4-pole alternator running at 25 rps then the frequency of induced emf is
(a)
phase sequence of 3-phase alternator can be reversed by
by changing the direction of field current
by changing the direction of field rotation
phase sequence cannot be reversed
The pitch factor for full pitch winding
0
0.5
1.5
1
Two alternators are mechanically coupled, driven with a common prime mover. one alternator delivers power at 50hz and another with 60hz. The maximum possible speed at the set would be ---
(a)
What is the Angular slot pitch α to eliminate 7th harmonic
1/7[pole pitch]
2/7[pole pitch]
[pole pitch]
6/7[pole pitch]
The coil span to eliminate 5th harmonic
1/5 [pole pitch]
3/5 [pole pitch]
4/5 [pole pitch]
6/5 [pole pitch]
A 3-phase alternator with slots per pole per phase is 5. The coil span is 12 slot pitches then the coil span factor Kp= -------
(a)
A 3-phase 8-pole 50 Hz machine. The speed of 7th space harmonic mmf wave is ---
750 rpm
107.14
1500
214.28
The speed of 30 th Harmonic
0
in the same direction of fundamental
in the opposite direction of fundamental
The effect of armature reaction for an alternator connected with upf load
purely demagnetization
purely cross magnetization
purely magnetization
All the above
If ferro magnetic material choosen is ideal then characterize the open circuit characteristics
Linearly rising
Non linear
partially linear and non linear
what is the power factor of the alternator at short circuit condition?
1
0 p.f. lead
0 p.f. lag
0.5 p.f. lag
What is the other names for EMF method to determine voltage regulation?
pessimistic method
synchronous impedance method
Both
None
What are the conditions to be satisfied for parallel operation
voltage
frequency
phase sequence
All the Above
The m.m.f. method is also known as
A-T Method
Optimistic method
Both
None
Which method is accurate in determining voltage regulation of an alternator
EMF method
MMF Method
ZPF method
None
In alternator if the load connected is ZPF lag then the armature current is
purely magnetizing
purely demagnetizing
purely cross magnetizing
None
Alternators are rated in terms of ---
KVA
KW
KVAR
None
The other name for ZPF method
EMF Method
MMF Method
potier method
ASA Method
