Related Questions

In case of synchronous motor, which of the following are true? a. Synchronous motor is not self-starting b. If the rotor poles are excited by field current and the stator terminals are connected to AC supply, motor vibrates. c. Variable frequency supply is used to start synchronous motor. d. By using frequency converter, a synchronous motor can be brought from standstill to its desired speed.
When the load on a reluctance motor is increased so that it cannot maintain synchronous speed, the motor will
Consider the following statements regarding synchronous machines: 1. When a synchronous motor is over-excited, its back emf is greater than the supply voltage 2. When a synchronous motor is over-excited, its power factor is leading 3. Synchronous motor is used as capacitor where load is so large that construction of a static capacitor is impractical Which of these statements are correct?
What is the distance covered by boat N upstream in 5 hours? Which of the following option is sufficient alone to find the answer? A) Boat M is travelling downstream with 20% more downstream speed of boat N. Speed of boat M in still water is 10% more than the speed of boat N in still water. B) Boat M and Boat N are travelling downstream with speed 33 km/hr and 40 km/hr respectively and speed of boat M is still water is 2 times the speed of stream. C) Speed of boat M in still water is 6 km/hr less then speed of boat N in still water and speed of stream is 10 km/hr. D) Speed of stream is ½ times the speed of boat N in still water and downstream speed of boat M is 44 km/hr. E) Speed of stream is 10 km/hr and ratio of upstream speed of boat M and boat N is 3 : 2 respectively.
A three-phase cylindrical rotor synchronous generator has a synchronous reactance Xs and a negligible armature resistance. The magnitude of per phase terminal voltage is VA and the magnitude of per phase induced emf is EA. Considering the following two statements, P and Q, P: For any three-phase balanced leading load connected across the terminals of this synchronous generator, VA is always more than EA Q: For any three-phase balanced lagging load connected across the terminals of this synchronous generator, VA is always less than EA Which of the following options is correct?
A synchronous motor installed at the receiving end substation operates with such an excitation that it takes power at lagging power factor. Now if the applied voltage of the synchronous motor goes down, the power factor of the synchronous motor will
Consider the following statements: 1. A synchronous motor has no starting torque but when started it always runs at a fixed speed. 2. A single-phase reluctance motor is not self-starting even if path for eddy currents are provided in the rotor 3. A single-phase hysteresis motor is self-starting Which of these statement(s) is/are correct?
If Rati travels at his usual speed for ‘x’ hours, he covers the same distance as he covered when he travels at a speed 30 km/hr less than usual, but for (x + 3) hours. Which of the following can be determined? (A) If he travels at 20 km/hr less speed than usual, he can cover a distance of 240 km in (x - 1) hours. What is the value of ‘x’? (B) If travels at his usual speed for (t + 2) hours, and at 50% of his usual speed for (t - 2) hours, his average speed for the journey is 68 km/hr. What is his usual speed? (C) His usual speed (in km/hr) is a multiple of 5 between 40 and 50 (both inclusive). If ‘x’ is a whole number, what is his usual speed? (D) If he travels at his usual speed for ‘t’ hours, he covers a distance of 400 km. What is the value of ‘x’?
Study the two cases and answer in terms of relation between the two cases Case 1: The average speed of the bike is \(3\frac{3}{4}\) times the average speed of the bus. A car covers 720 km in 10 hours. How much distance (in km) will a bike cover in 50 minutes if the speed of the bus is half of the speed of the car? Case 2: The average speed of bike is \(1\frac{2}{5}\) times the average speed of the car. A bus covers 441 km in 7 hours. How much distance (in km) will a bike cover in 45 minutes if the speed of the car is twice the speed of the bus?
Why is the three phase reluctance motor preferred over single phase reluctance motor?