HPCL Electrical Engineering Important Questions for Practice - Electrical4u

HPCL Electrical Engineering Important Questions for Practice There are 24 Questions are Available in this article if you are interested this type of Questions please leave a feedback in Comment box

Q1. The two winding of a transformer is 

Ans - Inductively Linked 

Q2.  A salient poles synchronous motor is running at no load . its field current is switched off. the motor will 

Ans - Continue to Run at Synchronous Speed

Q3. The Dc series motor should always be started with load because 

Ans - at no load , it will rotate at dangerously high speed 

Q4. The frequency of rotor current in 3 phase 50 Hz , 4 pole induction motor at full load speed is 

Ans - 2 Hz

Q5. In a Stepper motor the angular displacement 

Ans - Can be precisely controlled 

Q6. The power factor of a squirrel cage induction motor  is 

Ans - low at light load only 

Q7. the generation voltage is usually 

Ans - between 11kv to 33kv 

Q8. When a synchronous motor is running at synchronous speed , the damper winding produces 

Ans - No torque 

Q9. If a transformer primary is energised from a square wave source , it output voltage will be

Ans - A square wave 

Q10. In a dc series motor the electromagnetic torque developed is proportional to 

Ans - 12a

Q11. In a 3-phase induction motor running at slip 's' the mechanical power developed in terms of air gap power pg is 

Ans - (1 - SPg)

Q12. In a 3 - phase induction motor the maximum torque 

Ans - Directly proportional Square of rotor  induced EMF

Q13. In Dc machine the armature mmf is

Ans - Stationary W.r.t Field

Q14. In a transformer voltage regulation will be zero when operators is 

Ans - Leading power factor 

Q15. The maximum power in cylindrical and salient pole machine is obtained respectively at load angle of 

Ans  - Greater than 90 

Pmax = EV/Xs 

where , E = Excitation voltage 

            V = Terminal voltage 

           Xs = Synchronous reactance 

           sigma -  load angle 

Q16. The primary winding of a 220/6 v , 50 Hz supply . The secondary voltage will be 

Ans - 3.0 v

Q17. The Emf induced in the primary of a transformer 

Ans - leads the flus by 90 degree 

Q18. The relative speed between the magnetic field of a stator and rotor under steady state operation is zero for a 

a) DC Machine 

b) 3-phase induction machine 

c) synchronous speed 

d) single phase induction machine 

Ans - All options are correct 

Q19. The current from stator of an alternator is taken out to the external load circuit through 

Ans - solid connections 

Q20. A motor which can conveniently be operated at lagging as well as leading power factor is the 

Ans - synchronous motor 

Q21. A hysteresis motor 

Ans - is a constant speed motor 

Q22. The most suitable servomotor for low power applications is 

Ans - A Dc shunt motor 

Q23. The size of conductor used in power cables depends on the 

Ans - Current to be carried 

Q24. Two winding single phase transformer has a voltage regulations of 4.5 % at full load and unity power factor . at full load and 0.8 power factor lagging load the voltage regulation will be 

Ans - more than 4.5%

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