1
GATE EE 2014 Set 3
Numerical
+2
-0
The load shown in the figure absorbs 4 kW at a power factor of 0.89 lagging. Assuming the transformer to be ideal, the value of the reactance X to improve the input power factor to unity is ___________.
2
GATE EE 2014 Set 2
+2
-0.6
For a single phase, two winding transformer, the supply frequency and voltage are both increased by 10%. The percentage changes in the hysteresis loss and eddy current loss, respectively are
A
10 and 21
B
-10 and 21
C
21 and 10
D
-21 and 10
3
GATE EE 2014 Set 1
+2
-0.6
The core loss of a single phase, 230/115 V, 50 Hz power transformer is measured from 230 V side by feeding the primary (230 V side) from a variable voltage variable frequency source while keeping the secondary open circuited. The core loss is measured to be 1050 W for 230 V, 50 Hz input. The core loss is again measured to be 500W for 138 V, 30 Hz input. The hysteresis and eddy current losses of the transformer for 230 V, 50 Hz input are respectively.
A
508 W and 542 W
B
468 W and 582 W
C
498 W and 552 W
D
488 W and 562 W
4
GATE EE 2013
+2
-0.6
The following arrangement consists of an ideal transformer and an attenuator which attenuates by a factor of 0.8. An ac voltage VWX1 = 100V is applied across WX to get an open circuit voltage VYZ1 across YZ. Next, an ac voltage VYZ2 =100V is applied across YZ to get an open circuit voltage VWX2 across WX. Then, $$\frac{V_{YZ1}}{V_{WX1}}$$, $$\frac{V_{WX2}}{V_{YZ2}}$$ are respectively,
A
125/100 and 80/100
B
100/100 and 80/100
C
100/100 and 100/100
D
80/100 and 80/100
EXAM MAP
Medical
NEET