2
You visited us
2
times! Enjoying our articles?
Unlock Full Access!
Byju's Answer
Standard XII
Physics
Power in Electric Circuits
The V curve o...
Question
The V curve of an alternator is as shown in figure for rated armature current
I
a
of the machine is
A
more stable at P
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
equal stable at P and Q
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
not stable at P and Q
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
more stable at Q
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
Open in App
Solution
The correct option is
D
more stable at Q
P
s
y
=
E
V
X
s
c
o
s
δ
where
P
s
y
=
symmetrical power coefficient
P
s
y
∝
stability
∝
excitation
at 'Q' the excitation is more than at 'P'.
So it is more stable at Q.
Suggest Corrections
0
Similar questions
Q.
An 8 pole, DC machine has rated current of 100 A. If the armature is duplex lap wound, then the amount of current that will flow in each path at rated condition is ____ A.
Q.
A compensated dc machine has 20000 AT/Pole. The ratio of pole arc to pole pitch is 0.8. The interpolar airgap length and flux density arc 1.2 cm and 0.3 T. For rated armature current
I
a
=
1000
A, the number of turns on each interpole are
Q.
A three phase alternator has negligible stator resistance. A short circuit test is conducted on this alternator. At a particular speed a field current of
I
f
is required to drive the rated armature current. If the speed of the alternator is reduced to one fourth, the field current required to maintain armature current is
Q.
A DC shunt motor takes an rated armature current of 50 A at its rated voltage of 240 V. Its armature circuit resistance is 0.2
Ω
. If an external resistance of 1
Ω
is inserted in series with the armature and field flux remains unchanged. The percentage increase or decrease in speed for half of the load torque is
Q.
A 230 V dc shunt motor is used for adjustable speed drive over the range of 0 to 2000 rpm. Speed from zero to 1000 rpm are obtained by adjusting the armature terminal voltage from 0 to 230 V with field current kept constant. Speeds from 1000 to 2000 rpm are obtained by decreasing the field current with armature terminal voltage held constant at 230 V. Neglect armature reaction effects and losses, where
V
T
=
230
V
a
n
d
I
a
=
r
a
t
e
d
armature current at 1000 rpm. If torque required by load remains constant over the entire speed range. The curve for Power (P) vs Speed (N) is
View More
Join BYJU'S Learning Program
Grade/Exam
1st Grade
2nd Grade
3rd Grade
4th Grade
5th Grade
6th grade
7th grade
8th Grade
9th Grade
10th Grade
11th Grade
12th Grade
Submit
Related Videos
PHYSICS
Watch in App
Explore more
Power in Electric Circuits
Standard XII Physics
Join BYJU'S Learning Program
Grade/Exam
1st Grade
2nd Grade
3rd Grade
4th Grade
5th Grade
6th grade
7th grade
8th Grade
9th Grade
10th Grade
11th Grade
12th Grade
Submit
AI Tutor
Textbooks
Question Papers
Install app