- (a) Explain with diagrams what do you understand by
(i) In phase
As applied to sinusoidal quantities.
(b) A coil when connected to D.C supply of 100 volt takes 10 Ampere. When it is connected to A.C supply of 100 volt, 50 Hz it takes 5 Ampere. Calculate Resistance and Inductance of the coil.(4 Marks)
(a) State Thevenin's Theorem and explain it with the help of simple network. (5 Marks)
(b) What is resonance? (2 Marks)
- (a) Explain the significance of power factor in an A.C. circuit.
Calculate the value of load resistance R_L for maximum power transformation inthe circuit shown below. Also calculate the value of maximum power. (2+2 Marks)
(b) Describe in brief the working of a manual Voltage Stabiliser with its circuit diagram. (5 Marks)
- What are the methods of measurement of power in a 3- phase system? Explain two wattmeter methods. (2+4 Marks)
- (a) Deduce the e.m.f. equation of a transformer.
(b) Write merits and demerits of ordinary transformer and auto - transformer.
- (a) What is the principle of generation and motoring? Explain with block diagrams. (6 Marks)
- Explain with neat sketches the functions of each part of a D.C machine.Write the relationship between terminal voltage and induced e.m.f. for motoring and generating action. (6+4 Marks)
- Name various types of 1-phase motors.
(b) Explain the construction and principle of shaded pole motor. (7 Marks)
- What are the advantages and disadvantages of 3- phase induction motors over 1-phase induction motors? (4 Marks)
Electrical Engineering 2010 Question Papers Class XII