University of KwaZulu-Natal
School of Electrical, Electronic and Computer Engineering
Examinations: November 2017
Subject, Course & Code: ELECTRICAL MACHINES 2 – ENEL3MBH2
DURATION: 2 HOURS TOTAL MARKS: 100
Examiners: Dr. R. Pillay Carpanen (Internal)
Dr. R. Tiako (Moderator)
Instructions: Answer ALL Questions. Start answering each
question on a fresh page of the answer booklet.
The use of scientific calculators is permitted but
their memories must be cleared.
QUESTION 1 [38 Marks]
Open circuit and short circuit tests were done on a three-phase, 15 kV, 195 MVA,
60 Hz, round-rotor, Y-connected synchronous generator having a stator
resistance of 0.03 Ω per phase. The following test data were obtained:
Open circuit test
IX (A) 150 300 450 600 750 900 1200
EOC (LINE) (kV) 3.75 7.5 11.2 13.6 15 15.8 16.5
Short circuit test
IX = 750 A, ISC = 7000 A.
(a) Draw the open-circuit characteristic, short circuit characteristic, the air
gap line and the modified air gap line. [10]
Page 1 of 3
School of Electrical, Electronic and Computer Engineering
Examinations: November 2017
Subject, Course & Code: ELECTRICAL MACHINES 2 – ENEL3MBH2
DURATION: 2 HOURS TOTAL MARKS: 100
Examiners: Dr. R. Pillay Carpanen (Internal)
Dr. R. Tiako (Moderator)
Instructions: Answer ALL Questions. Start answering each
question on a fresh page of the answer booklet.
The use of scientific calculators is permitted but
their memories must be cleared.
QUESTION 1 [38 Marks]
Open circuit and short circuit tests were done on a three-phase, 15 kV, 195 MVA,
60 Hz, round-rotor, Y-connected synchronous generator having a stator
resistance of 0.03 Ω per phase. The following test data were obtained:
Open circuit test
IX (A) 150 300 450 600 750 900 1200
EOC (LINE) (kV) 3.75 7.5 11.2 13.6 15 15.8 16.5
Short circuit test
IX = 750 A, ISC = 7000 A.
(a) Draw the open-circuit characteristic, short circuit characteristic, the air
gap line and the modified air gap line. [10]
Page 1 of 3
