Quiz: Electrical Engineering 26 Nov 2020

Quiz: Electrical Engineering
Exam: UPPCS AE
Topic: Miscellaneous

Each question carries 1 mark.
Negative marking: 1/3 mark
Time: 10 Minute

Q1. The slip ring of wound rotor machine is made from
(a) Mild steel
(b) electrolytic copper
(c) cast iron
(d) brass
L1Difficulty 3
QTags Machine
QCreator Balwant Kumar

Q2. Which type of the following will result in a symmetrical fault?
(a) All the three phases to earth
(b) phase to line
(c) single phase to earth
(d) two phases to earth
L1Difficulty 3
QTags Switchgear and protection
QCreator Balwant Kumar

Q3. The Merz price protection is suitable for?
(a) Alternator
(b) transformer
(c) Feeder
(d) Transmission line
L1Difficulty 3
QTags Switchgear and protection
QCreator Balwant Kumar

Q4. Internal fault of Transformer is detected and protected by?
(a) Directional relay
(b) Thermal relay
(c) Buchholz relay
(d) Distance relay
L1Difficulty 3
QTags Switchgear and protection
QCreator Balwant Kumar

Q5. The most common type of fault is
(a) Single phase to ground
(b)Two phase to ground
(c) Phase to phase
(d) three phases to ground
L1Difficulty 3
QTags Switchgear and protection
QCreator Balwant Kumar

Q6. The per unit value of a 60 Ω resistance at 1000 MVA base and 100 kV base voltage is
(a) 4 pu
(b)8 pu
(c)6 pu
(d)10 pu
L1Difficulty 3
QTags Switchgear and protection
QCreator Balwant Kumar

Q7. If the fault current is 2000 A for a relay with a current setting of 50 % and CT ratio of 1000:1, the PSM would be:
(a) 1.5
(b) 4
(c) 4.5
(d) 3
L1Difficulty 3
QTags Switchgear and protection
QCreator Balwant Kumar

Q8. Current limiting reactors may be
(a) oil immersed non magnetically shielded
(b) oil immersed magnetically shielded
(c) air cored air cooled
(d) any of above
L1Difficulty 3
QTags Switchgear and protection
QCreator Balwant Kumar

Q9. Which semiconductor device behaves like two SCR’s?
(a) UJT
(b) MOSFET
(c) JEET
(d) Triac
L1Difficulty 2
QTags Semiconductors & diodes
QCreator Balwant Kumar

Q10.The power factor at which single phase induction motor usually operate is
0.7 lag
0.8 lag
0.7 lead
Unity
L1Difficulty 1
QTags Single phase induction motor
QCreator Balwant Kumar

Solutions

S1. Ans.(d)
Sol. Brass

S2. Ans.(a)
Sol. All the three phases to earth fault will result in the symmetrical fault.

S3. Ans.(a)
Sol. Alternator

S4. Ans.(c)
Sol. Internal fault of Transformer is detected and protected by Buchholz Relay.

S5. Ans. (a)
Sol. The most common type of fault is Single phase to ground.

S6. Ans. (c)
Sol. Rpu = R(ohm) ×MVA/(kV)^2
= 60 ×1000/100^2 = 6 p.u.
S7. Ans. (b)
Sol. PSM=(Fault current )/(Current setting ×CT ratio×Rated secondary current)
After putting the value in the given formulae 4 is the answer.

S8. Ans. (d)
Sol. Any of above

S9. Ans (d)
sol. Triac

S10. Ans (a)
single phase induction motor usually operate is 0.7 lag.