ELECTROMECHANICAL ENERGY CONVERSION-II
SEM-IV, 2013
B.TECH EXAMINATION
UTTARAKHAND TECHNICAL UNIVERSITY
utu question paper
Attempt any four:
5*4=20
- How a
synchronous machine is different from an Induction machine?
- What is known as
Hunting in Synchronous machine?
- Explain the
working principle of a synchronous motor with neat diagram.
- Explain the
principle of operation of infinite bus.
- Explain what is
armature reaction in synchronous machine.
- What are the
conditions necessary for the parallel operation of synchronous generators?
Attempt any four:
5*4=20
- Discuss the
effect of excitation on armature current and power factor of a synchronous
motor.
- How to determine
Xd and Xq of a synchronous machine from
slip test? Explain with neat diagram.
- Discuss briefly
about synchronous condenser.
- What do you
understand by V curves of a synchronous machine?
- Discuss any one
method of starting of synchronous machine.
- Explain the two
reaction theory of a synchronous machine.
Attempt any two:
10*2=20
- A large 3-phase,
4000V, 50Hz squirrel-cage induction motor draws a current of 380A and a
total active power of 2344kW when operating at full load. The speed at
full load is accurately measured and found to be 742rpm. The stator is
wye-connected and the resistance between two stator terminals is
0.1 Ω. The total iron losses are 23.4kW and the windage and friction
losses are 12kW.Calculated:(i)The power factor at full load (ii)The active
power supplied to the rotor (iii)The mechanical power output to the load
and torque delivered to the load (iv)The motor's net efficiency.
- A two pole,
3300V, 50Hz 3-phase induction motor produces rated torque (1 per unit) at
a speed of 2870rpm. If the machine produces maximum torque at
2218rpm:(i)determine the per unit value of the maximum torque
(ii)determine the per unit value of the starting torque (iii)does the
answer in (ii)indicate that the rotor resistance is relatively high or
relatively low?
- Explain in
detail with the help of neat diagram the principle of operation of a three
phase induction motor.
Attempt any two:
10*2=20
- What are the
different starting methods of single phase induction motor? Explain any
one of them.
- Describe the
procedure for no load and blocked rotor test.
- Write a short
note on double field revolving theory regarding single phase induction
motor.
Attempt any two:
10*2=20
- Explain the
constructional detail of a universal motor, with the help of neat diagram.
- How speed of a
stepper motor can be controlled? What are the various schemes for that?
- What are the
various advantages of a single phase ac series compensated motor?
-----------------------------------------------
No comments:
Post a Comment