END TERM EXAMINATION
DECEMBER 2015-JANUARY 2016
Time: 3 hours Maximum Marks:75
☞Note: Attempt any five questions including Q.No.1 which is compulsory. Select one question from each unit. Assume missing data if any.
(a) State and explain reciprocity theorem?
(b) What is the significance of back emf in DC motor?
(c) Explain working of electronic energy meter?
(d) Classify instruments and clearly differentiate between absolute and secondary instruments?
(e) What is slip of an induction motor? How does it vary with load?
(a) State and explain Thevenin’s theorem.
(b) Calculate the value of load resistance in branch AB,
So that the maximum power is transferred to the load of the circuit shown along side.
(a) State and explain Millman’s theorem.
(b) Drive expression for converting a star network to a delta equivalent network.
(a) Explain the term RMS value, Average value and form factor w.r.t alternating quantity. Deduce the value of form factor of a sinusoidal voltage.
(b) Explain the concept of bandwidth and quality factor for a series RLC circuit. Drive theor expression.
(a) State the advantages of three phase system over single phase system.
(b) Find the capacitance which must be connected in series with a 100 W, 110 V lamp in order that the lamp may draw may draw its normal current when the combination is connected to a 230 V 50 Hz supply.
(a) Describe deflecting torque, controlling torque and damping torque in case of indicating type instruments giving the significance of each one of them
(b) Explain the construction and working of permanent magnet moving coil (PMMC) instruments.
(a) Explain 2 Watt-meter method of measuring power in a three phase AC circuit with the help of suitable circuit diagram.
(b) Discuss digital voltmeter and its applications.
(a) What are the factors that affect the speed of DC motor? Also explain how the speed can be controlled above and below the normal speed.
(b) Explain the open circuit and short circuit test as performed for single phase transformer and why it is performed.
(a) Drive the emf equation of a transformer.
(b) Explain hysteresis and eddy current losses. How they are minimise to three phase induction motor.