________________ frequency is not common in low frequency traction system?

Related Mcqs:

1. Which of the following is an advantage of electric traction over other methods of traction ?

   A. Faster acceleration
   B. No pollution problems
   C. Better braking action
   D. All of the above

2. Which of the following is the disadvantage of electric traction over other systems of traction ?

   A. Corrosion problems in the under-ground pipe work
   B. Short time power failure interrupts traffic for hours
   C. High capital outlay in fixed installations beside route limitation
   D. Interference with communication lines
   C. All of the above

3. Main traction systems used in India are, those using______________?

   A. electric locomotives
   B. diesel engine locomotives
   C. steam engine locomotives
   D. diesel electric locomotives
   E. all of the above

4. Series motor is not suited for traction duty due to which of the following account ?

   A. Less current drain on the heavy load torque
   B. Current surges after temporary switching off supply
   C. Self relieving property
   D. Commutating property at heavy load

5. An ideal traction system should have_______________?

   A. easy speed control
   B. high starting tractive effort
   C. equipment capable of with standing large temporary loads
   D. all of the above

6. Which of the following methods is used to control speed of 25 kV, 50 Hz single phase traction ?

   A. Reduced current method
   B. Tap changing control of transformer
   C. Series parallel operation of motors
   D. All of the above

7. Which of the following motors is preferred for traction work ?

   A. Universal motor
   B. D.C. series motor
   C. Synchronous motor
   D. Three-phase induction motor

8. A sinusoidal voltage with a peak-to-peak value of 18 V is applied to an RC low-pass filter. If the reactance at the input frequency is zero, the output voltage is____________?

   A. 18 V peak-to-peak
   B. zero
   C. 9 V peak-to-peak
   D. 12.74 V peak-to-peak

9. The maximum output voltage of a certain low-pass filter is 15 V. The output voltage at the critical frequency is_____________?

   A. 10.60 V
   B. 0 V
   C. 21.21 V
   D. 15 V

10. An RC low-pass filter consists of a 120 Ω resistor and a 0.002 µF capacitor. The output is taken across the capacitor. The circuit’s critical frequency is___________?

    A. 333 kHz
    B. 633 kHz
    C. 331 kHz
    D. 60 kHz