Code No:RR210205
RR
SET-1
B.Tech II Year - I Semester Examinations, December 2011
ELECTRO MECHANICS - I
(ELECTRICAL AND ELECTRONICS ENGINEERING)
Time: 3 hours
Max. Marks: 80
Answer any five questions
All questions carry equal marks
--1.a)
b)
Explain the concept of dc machine operations as a generator and also as a motor.
Discuss the constructional features of dc generator.
[16]
2.a)
A 4 – pole tap wound dc armature has a core diameter of 0.7 meter. It has 560
conductors and the ratio of pole arc/pole pitch is 0.63. If the armature is running
at 600 r.p.m and the flux density in the air gap is 1.2 wb / m2. Determine the
induced emf in the armature if effective length of armature conductors is 20 cm2.
Define Pole pitch, Back pitch, Front pitch in case of dc machine.
[16]
b)
3.a)
b)
Explain the external characteristics of dc shunt generator and state the condition
when the load voltage falls to zero.
List the conditions for building up of a dc shunt generator.
[16]
4.
A 4 – pole series motor has 944 wave – connected armature conductors. At a
certain load the flux per pole is 34.6 mwb and the total mechanical torque
developed is 209 Nm. Calculate the line current taken by the motor and speed at
which it will run with an applied voltage of 500V. Total armature resistance is
3Ω .
[16]
5.
Explain the function of two coils used in 3 – point starter with a neat sketch.
[16]
6.
Explain Hopkinson’s test conducted on dc machine.
[16]
7.
Discuss the various methods of speed control of dc shunt motors.
[16]
8.
A 230V dc shunt motor with constant field drives a load whose torque is
proportional to the speed. When running at 750rpm it taken 30A. Find the speed
at which it will run if a 10 Ω resistance is connected in series with it’s armature.
The resistance of armature may be neglected.
[16]
********
Code No:RR210205
RR
SET-2
B.Tech II Year - I Semester Examinations, December 2011
ELECTRO MECHANICS - I
(ELECTRICAL AND ELECTRONICS ENGINEERING)
Time: 3 hours
Max. Marks: 80
Answer any five questions
All questions carry equal marks
--1.a)
b)
Explain the external characteristics of dc shunt generator and state the condition
when the load voltage falls to zero.
List the conditions for building up of a dc shunt generator.
[16]
2.
A 4 – pole series motor has 944 wave – connected armature conductors. At a
certain load the flux per pole is 34.6 mwb and the total mechanical torque
developed is 209 Nm. Calculate the line current taken by the motor and speed at
which it will run with an applied voltage of 500V. Total armature resistance is
[16]
3Ω .
3.
Explain the function of two coils used in 3 – point starter with a neat sketch.
[16]
4.
Explain Hopkinson’s test conducted on dc machine.
[16]
5.
Discuss the various methods of speed control of dc shunt motors.
[16]
6.
A 230V dc shunt motor with constant field drives a load whose torque is
proportional to the speed. When running at 750rpm it taken 30A. Find the speed
at which it will run if a 10 Ω resistance is connected in series with it’s armature.
The resistance of armature may be neglected.
[16]
7.a)
b)
Explain the concept of dc machine operations as a generator and also as a motor.
Discuss the constructional features of dc generator.
[16]
8.a)
A 4 – pole tap wound dc armature has a core diameter of 0.7 meter. It has 560
conductors and the ratio of pole arc/pole pitch is 0.63. If the armature is running
at 600 r.p.m and the flux density in the air gap is 1.2 wb / m2. Determine the
induced emf in the armature if effective length of armature conductors is 20 cm2.
Define Pole pitch, Back pitch, Front pitch in case of dc machine.
[16]
b)
********
Code No:RR210205
RR
SET-3
B.Tech II Year - I Semester Examinations, December 2011
ELECTRO MECHANICS - I
(ELECTRICAL AND ELECTRONICS ENGINEERING)
Time: 3 hours
Max. Marks: 80
Answer any five questions
All questions carry equal marks
--1.
Explain the function of two coils used in 3 – point starter with a neat sketch.
[16]
2.
Explain Hopkinson’s test conducted on dc machine.
[16]
3.
Discuss the various methods of speed control of dc shunt motors.
[16]
4.
A 230V dc shunt motor with constant field drives a load whose torque is
proportional to the speed. When running at 750rpm it taken 30A. Find the speed
at which it will run if a 10 Ω resistance is connected in series with it’s armature.
The resistance of armature may be neglected.
[16]
5.a)
b)
Explain the concept of dc machine operations as a generator and also as a motor.
Discuss the constructional features of dc generator.
[16]
6.a)
A 4 – pole tap wound dc armature has a core diameter of 0.7 meter. It has 560
conductors and the ratio of pole arc/pole pitch is 0.63. If the armature is running
at 600 r.p.m and the flux density in the air gap is 1.2 wb / m2. Determine the
induced emf in the armature if effective length of armature conductors is 20 cm2.
Define Pole pitch, Back pitch, Front pitch in case of dc machine.
[16]
b)
7.a)
b)
8.
Explain the external characteristics of dc shunt generator and state the condition
when the load voltage falls to zero.
List the conditions for building up of a dc shunt generator.
[16]
A 4 – pole series motor has 944 wave – connected armature conductors. At a
certain load the flux per pole is 34.6 mwb and the total mechanical torque
developed is 209 Nm. Calculate the line current taken by the motor and speed at
which it will run with an applied voltage of 500V. Total armature resistance is
[16]
3Ω .
********
Code No:RR210205
RR
SET-4
B.Tech II Year - I Semester Examinations, December 2011
ELECTRO MECHANICS - I
(ELECTRICAL AND ELECTRONICS ENGINEERING)
Time: 3 hours
Max. Marks: 80
Answer any five questions
All questions carry equal marks
--1.
Discuss the various methods of speed control of dc shunt motors.
2.
A 230V dc shunt motor with constant field drives a load whose torque is
proportional to the speed. When running at 750rpm it taken 30A. Find the speed
at which it will run if a 10 Ω resistance is connected in series with it’s armature.
The resistance of armature may be neglected.
[16]
3.a)
b)
Explain the concept of dc machine operations as a generator and also as a motor.
Discuss the constructional features of dc generator.
[16]
4.a)
A 4 – pole tap wound dc armature has a core diameter of 0.7 meter. It has 560
conductors and the ratio of pole arc/pole pitch is 0.63. If the armature is running
at 600 r.p.m and the flux density in the air gap is 1.2 wb / m2. Determine the
induced emf in the armature if effective length of armature conductors is 20 cm2.
Define Pole pitch, Back pitch, Front pitch in case of dc machine.
[16]
b)
5.a)
b)
[16]
Explain the external characteristics of dc shunt generator and state the condition
when the load voltage falls to zero.
List the conditions for building up of a dc shunt generator.
[16]
6.
A 4 – pole series motor has 944 wave – connected armature conductors. At a
certain load the flux per pole is 34.6 mwb and the total mechanical torque
developed is 209 Nm. Calculate the line current taken by the motor and speed at
which it will run with an applied voltage of 500V. Total armature resistance is
[16]
3Ω .
7.
Explain the function of two coils used in 3 – point starter with a neat sketch.
[16]
8.
Explain Hopkinson’s test conducted on dc machine.
********
[16]