NTPC Executive Trainee Previous test paper ( Electrical)

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National Thermal Power Corporation (NTPC) recruits young engineers every year through  written exam in the month of April followed by group discussion and personal interview. Test pattern consists of Technical and General awareness sections. Duration 2hrs. Some of the sample test questions are provided here 

1. Impedance relay is used for:

a) Phase faults

b) Earth fault

c) both phase fault and earth fault

d) none of the above

2. Series capacitors are used in transmission lines for:

a) Compensate the voltage drop

b) Reduce the line losses

c) Limit the short circuit current

d) Improve load power factor 

3. The surge impedance of a 3phase500kV transmission line is 500ohms. The surge impedance loading of the line is

a) 500MW

b) 1000MW

c) 1500MW

d) 2500MW

4. Bundled conductors used in EHV transmission to reduces the

a) Surge impedance of line

b) Voltage drop of the line

c) corona loss of the line

d) I²R loss of the line

5. Which bridge is used to determine the frequency:

a) Anderson bridge

b) De Sauty bridge

c) Wein bridge

d) Campbell bridge 

6. Which plant is used as base load plant

a) Thermal plant

b) Hydro plant

c) Nuclear plant

d) Gas plant

7. Which one of the following is zero as applied to electomagnetic fields:

a) grad div A

b) div grad V

c) div curl A

d) curl curl A 

8. An electric circuit consists of 12 branches and 8 nodes will have

a) 4 loop equations

b) 5 loop equations

c) 7 loop equations

d) 8 loop equations 

9. dv/dt protection for scr can be achieved by

a) R and L in series to SCR

b) R and L in parallel to SCR

c) R and C in series to SCR

d) R and C in parallel to SCR 

10. The current drawn by a 220V d.c motor with back emf of 210V and armature resistance of 0.4 ohms is:

a) 4 A b) 25A c) 8A c) 16A 

11.The emf induced in the primary of the transformer:

a) Leads the flux by 90^o

b) In phase with the flux

c) Lags the flux by 90^o

d) Is in phase apposition with the flux. 

12. Induction motor under no load will have power factor of:

a) 0.80 lag

b) 0.70 lag

c) 0.50 lag

d) 0.20 lagl

 Answers:

(1) a   (2) a   (3) a  (4) c
(5) c   (6) c   (7) c  (8) b

(9) d (10) a (11) c (12) d