Electrical Engineering Answers

3. Explain how a rotating magnetic field makes the rotor of an induction motor to rotate?

2. Explain Core losses in a transformer? How to minimize these losses?

1. A 30 KVA transformer has 300 turns on the primary and 50 turns on the secondary winding. The primary is connected to 1500 V, 50 Hz supply. Find
1) the full load primary and secondary currents
2) the secondary emf
3) maximum flux in the core

6. Explain the VI characteristics of Common Emitter NPN Transistor with all necessary diagrams?

5. How NOR Gate act as universal gate, justify your answer

Explain the significance of Noise Margin? Calculate the Noise Margin for the hardware system following static discipline with voltage levels provided below:
VIL = 1.7 V VIH = 3.2 V VOL = 0.6 V VOH = 4.4 V

3. Explain why single phase Induction motor is NOT self-starting?

2. Does transformers work on DC? Justify your answer.

1. A 50 KVA transformer has 400 turns on the primary and 50 turns on the secondary winding. The primary is connected to 2000 V, 50 Hz supply. Find
1) the full load primary and secondary currents
2) the secondary emf.
3) maximum flux in the core

2 mWb is to be produced in the air gap of the magnetic circuit shown in figure 21.17. How much ampere turns the coil must provide to achieve this? Relative permeability μr of the core material may be assumed to be constant and equal to 5000. All the dimensions shown are in cm and the sectional area is 25cm2 through out.