Electrical Machines
Induction Machines
Marks 1Marks 2
Synchronous Machines
Marks 1Marks 2Marks 5
1
GATE EE 2007
MCQ (Single Correct Answer)
+2
-0.6
A single-phase $$50$$ $$kVA,$$ $$250$$ $$V/500V$$ two winding transformer has an efficiency of $$95\% $$ at full load, unity power factor. If it is reconfigured as a $$500V/750V$$ auto-transformer, its efficiency at its new rated load at unity power factor will be
A
$$95.752\% $$
B
$$97.851\% $$
C
$$98.276\% $$
D
$$99.241\% $$
2
GATE EE 2006
MCQ (Single Correct Answer)
+2
-0.6
A $$300$$ $$kVA$$ transformer has $$95\% $$ efficiency at full load $$0.8$$ $$pf$$ lagging and $$96\% $$ efficiency at half load, unity $$pf.$$

What is the maximum efficiency (in %) at unity $$pf$$ load?

A
$$95.1$$
B
$$96.2$$
C
$$96.4$$
D
$$98.1$$
3
GATE EE 2006
MCQ (Single Correct Answer)
+2
-0.6
Two transformers are to be operated in parallel such that they share load in proportion to their $$kVA$$ ratings. The rating of the first transformer is $$500$$ $$kVA$$ and its $$pu$$ leakage impedance is $$0.05$$ $$pu.$$ If the rating of second transformer is $$250$$ $$kVA,$$ its $$pu$$ leakage impedance is
A
$$0.20$$
B
$$0.10$$
C
$$0.25$$
D
$$0.025$$
4
GATE EE 2006
MCQ (Single Correct Answer)
+2
-0.6
A $$300$$ $$kVA$$ transformer has $$95\% $$ efficiency at full load $$0.8$$ $$pf$$ lagging and $$96\% $$ efficiency at half load, unity $$pf.$$

The iron loss $$\left( {{P_i}} \right)$$ in $$kW,$$ under full load operation are

A
$${P_c} = 4.12,\,\,{P_i} = 8.51$$
B
$${P_c} = 6.59,\,\,{P_i} = 9.21$$
C
$${P_c} = 8.51,\,\,{P_i} = 4.12$$
D
$${P_c} = 12.72,\,\,{P_i} = 3.07$$
GATE EE Subjects
Electromagnetic Fields
Signals and Systems
Engineering Mathematics
General Aptitude
Power Electronics
Power System Analysis
Analog Electronics
Control Systems
Digital Electronics
Electrical Machines
Electric Circuits
Electrical and Electronics Measurement