ASYNCHRONOUS MACHINES (EEEP3208)
Electrical and Electronic Engineering - EEE
Semester: Second Semester
Level: 300
Year: 2019
THE UNIVERSITY OF BAMENDA
COLLEGE OF TECHNOLOGY S
SECOND SEMESTER EXAMS
DEPARTMENT: ELECTRICAL AND POWER ENGINEERING
COURSE EEEP3208 ASYNCHRONOUS MACHINES
Duration: 1h30mins
Instruction: No documents authorized
EXERCISE A (10mks)
1.
Explain why some motors are said to be “Induction motors”?
2.
State explicitly but briefly why the rotor of a three phase induction motor rotate.
3.
Define the Double-field Revolving Theory.
4.
What is the consequence on a three phase induction motor in case the Rotor speed matches or equals the speed of
the stator magnetic field?
Exercise B(6Mks)
1.
State how we can cause a single phase motor to be self starting.
2.
With the help of suitable diagrams and their respective phasor diagrams describe the following methods of single
phase motor starting.
i.
Split phase motors
ii.
Capacitor start and Induction run.
Exercise 3.(3Mks)
A 4-pole, 3-phase induction motor operates from a supply whose frequency is 50 Hz. Calculate :
(i) the speed at which the magnetic field of the stator is rotating.
(ii) the speed of the rotor when the slip is 0.04.
(iii) the frequency of the rotor currents when the slip is 0.03.
(iv) the frequency of the rotor currents at standstill.
Exercise 4
1. Orderly presentation of your work (1Mk)
AWEH K. BLESS
Good luck
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