74.       What is the Principle of operation of DC Generator?

75.       Derive the emf equation of a two pole Dc generator

76.       Describe the open circuit characteristics of DC generator?

77.       Why is a DC generator not suitable for general electric supply?

78.       What is the difference between the excitation systems of dc shunt generator and dc series generator?

79.       Adc machine developes an open circit emf of 250Vat 1500 rpm find the developed torque for armature current of 20 A

80.       Why are synchronous motors not self starting?

81.       How can the direction of stator revolution field be reversed?

82.       What are the various losses in Induction Motor? Onwhat factor do they depend?

83.       Give various methods of startinglarge induction motors Explain auto transformer starter in detail

84.       A 6 pole ,3 phase ,50 Hz induction motor developes maximum torque of 20 kgm at a speed of 970 rpm Determine the torque exerted by the motor at 4%slip the rotor4 resistance per phase is 0.5ohm

85.       Explain the working of domestic electric fan  how is its speed controlled?

86.       State why the core of the transformer should be made of a magnetic  material and why is the core laminated?

87.       Explain the phasor diagram of transformer under loaded condition?

88.       State and prove the condition under which transformer operates at  maximum efficiency?

89.       Explain the difference between moving coil and moving iron type instruments ?

90.       find all day efficiency of a transformer having maximum efficiency of 98% at 15 KVA at unity power factor and loaded as follows:12 hours -2KW at 0.5 lag

                  6 hours -12 KW at 0.8 lag

                   6 hours –at no-load