Important Questions in  Electrical Drives and Controls 131305
subject for NOV/DEC 2011 AUT ANNA UNIVERSITY OF TECHNOLOGY EXAMINATIONS FOR SECOND YEAR THIRD SEMESTER MECH Students

Note: Please Note That These are only important questions from each units may or may not be ask for university exams - Thanks Admin

131305 - Electrical Drives and Controls

UNIT I

1.   Draw the typical temperature rise-time curve and derive the equation for temperature rise in an electric drive.
2.   Explain the loading of an electric motor and its duty cycle with a simple diagram.
3.   Explain in detail about the various types of electric drives.
4.   Discuss in detail the determination of power rating of motors.
5.   At full load of a 10 H.P. the temperature rise of a motor is 25°C after one hour and 40°C after two hours. Find (1) the final temperature rise on full load (2) heating time constant of motor (3) half hour rating if iron losses which remain constant are 80% of copper losses at full load.

UNIT II

1.   Establish the basic characteristics of the dc machines from the fundamental equations pertaining to dc machines
2.   How does the change in supply voltage affect the separately excited motor and fluctuation in load torques affect the series motor?
3.   Explain the Speed-Torque characteristics of three phase induction motor with neat diagrams.
4.   Discuss any two methods for modifying the speed torque characteristics of a 3 phase induction motor

UNIT III
1.   Draw a neat diagram of the 4-point starter used for a DC shunt motor.
2.   Explain with neat circuit diagram, the star-delta starter method of starting squirrel cage induction motor.
3.   Explain with neat diagram the starting of three phase slip ring induction motor.

4.   Explain the different starting methods of three phase squirrel cage induction motors with neat sketches.

UNIT IV

1.   Explain with neat sketch the chopper control method of speed control of DC Motors.
2.   Discuss the Ward-Leonard speed control system with a neat circuit diagram. Also mention its advantages and disadvantages.
3.   Explain the different methods of speed control employed in DC Shunt Motor.
4.   Draw and discuss a speed control scheme of a spearately excited dc motor using dc choppers.

UNIT V
1.   Draw the power circuit arrangement of three phase variable frequency inverter for the speed control of three phase induction motor and explain its working.
2.   Explain in detail about Slip power recovery scheme.
3.   Explain the working of following methods with neat circuit diagram.
a)    Kramer system a) Scherbius system
4.   Explain the solid state stator voltage control technique for the speed control of three phase induction motor.

Important Questions in Electrical Drives and Controls 131305 subject for NOV/DEC 2011 AUT ANNA UNIVERSITY OF TECHNOLOGY EXAMINATIONS FOR SECOND YEAR THIRD SEMESTER MECH Students Reviewed by Rejin Paul on 10:15 PM Rating: 5