1.a. Why equalizer connection is necessary for the armature winding of a dc machine with lap-winding..

1.b. What are the various method of improving communication.

1.c. what are the significance of back EMF ?

1.d. Draw the torque -urrent characteristics of DC compound motors.

1.e. Hopkinson's test is also called as regenerative test.justify.?

1.f. What are the advantage and disadvantage of Hopkinson's test?

1.g. Draw the exact equivalent circuit of transforme.

1.h. what what is stacking factor? What is its approximate value?

1.i. What are the advantage of autotransformer over two winding transformer?

1.j. why OC-test conducted on LV -side and SC-test conducted on HV-side?

2.a. Explain the concept of Armature reaction and how it overcomes.

2.b. A dc shunt generator has the following open circuit magnetization curve running at 800 rpm Field current (A) : 0 0.5 1.0 2.0 3.0 4.0 5.0 EMF(V) : 10 50 100 175 220 245 262 Find graphically the critical resistance of shunt field circuit. If the field resistance is changed to 75ohms,what will be the critical speed for the machine to build up.

3.a. Distinguish between self excited and separately excited DC Generator. Give the circuit diagram of self excited DC Generator and derive the voltage equation .

3.b. Draw e.m.f equation of d.c generator.

4.a. Draw and explain the Electrical characteristics of DC series and shunt motor.

4.b. Drive the expression for the speed of a DC motor in terms of back emf and flux per role.

5.a. Explain with neat sketch the function of 3-point starter.

5.b. A dc shunt motor take 1.5A on no load when connected to 250V main with an armature resistance of 1.0$\Omega$ when the field current is is 0.5A.Determine the load current corresponding to maximum efficiency.

6.a. Explain the procedure to separate the the stray losses in DC motor.

6.b. hopkinson's test on two similar DC shunt machines gave the following data: Line voltage 230V, line current excluding both the field current is 40A, motor armature current 350A field current 5A and 4.2A. Calculate the efficiency of each machine. Armature resistance of the machine is is 0.02$\Omega$.

7. With a neat sketch explain the procedure of swinburne's test? Mention its advantage and disadvantage.

8. Discuss the working principle of single phase Transformer and also explain the construction details.

9.a. Explain why hysteresis and Eddy current losses occur in Transformer. What are the methods to reduce this losses.

9.b. Draw and explain the phasor diagram of single phase transformer on load considering with winding resistance.

10. Drive the equations for the current supplied by each Transformer when two Transformer are operating in parallel with equal and unequal ratios.

11.a. What is auto transfermer? Explain the working principle of auto Transformer.

11.b. What are the advantage of poly phase Transformer? Give different configurations.