1
GATE EE 1998
MCQ (Single Correct Answer)
+1
-0.3
The magnetizing current in a transformer is rich in
A
3rd harmonic
B
5th harmonic
C
7th harmonic
D
13th harmonic
2
GATE EE 1998
MCQ (Single Correct Answer)
+2
-0.6
Match the following

List-I (Test)
(A) No load and blocked rotor test
(B) Sumpner’s test
(C) Swinburn’s test

List-II (Machine)
(1) Transformer
(2) Induction machine
(3) Synchronous machine
(4) DC machine

A
$$\begin{array}{l}A\;\;\;B\;\;\;C\\2\;\;\;\;1\;\;\;\;4\end{array}$$
B
$$\begin{array}{l}A\;\;\;B\;\;\;C\\1\;\;\;\;2\;\;\;\;4\end{array}$$
C
$$\begin{array}{l}A\;\;\;B\;\;\;C\\4\;\;\;\;3\;\;\;\;1\end{array}$$
D
$$\begin{array}{l}A\;\;\;B\;\;\;C\\4\;\;\;\;1\;\;\;\;3\end{array}$$
3
GATE EE 1998
MCQ (Single Correct Answer)
+2
-0.6
A 50 Hz transformer having equal hysteresis and eddy current losses at rated excitation is operated at 45 Hz at 90% of its rated voltage. Compared to rated operating point, the core losses under this condition:
A
reduce by 10%
B
reduce by 19%
C
reduce by 14.5%
D
remain unchanged
4
GATE EE 1998
MCQ (Single Correct Answer)
+1
-0.3
The efficiency of a 100 kVA transform is 0.98 at full as well as at half load. For this transformer at full load the copper loss.
A
is less than core loss
B
is equal to core loss
C
is more than core loss
D
none of the above