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Q1. (a) Draw a 4-pole D.C. generator construction diagram labelling its main parts. (8)

(b) Describe briefly its (8)

(i) Field system

(ii) Armature

(iii) Commutator

(iv) Brushes

Q2. If the motor terminal markings are unknown how would you identify the start, run and common terminal connections. (16)

Q3. (a) Sketch and describe the working of a Lead-Acid battery. (12)

(b) What routine maintenance is carried out on these batteries? (4)

Q4. With the aid of a circuit diagram, explain how a Galvanometer can be used as an Ammeter. (16)

Q5. With the aid of a simple circuit diagram, explain the electrical distribution system for essential loads on board a cargo ship. (16)

Q6. (a) Explain Kirchhoff’s current law (6)
(b) In the given circuit, find the current value I₂. (10)

Q7. (a) Compare constant current method and constant voltage method of charging batteries. (6)
(b) The filament of a 230V lamp takes a current of 0.261A when working at its normal temperature of 2000° C. The temperature coefficient of the tungsten filament material can be taken as 0.005 /ºC at 0°C. Find the approximate current which flows at the instant of switching on the supply to the cold lamp, which can be considered to be at a room temperature of 20° C (10)

Q8. (a) Define work, Power and Efficiency (6)
(b) A shunt motor has an armature resistance of 0.2 ohms and with an armature current of 120 amperes runs at 750 r.p.m. off a 400-volt supply. Calculate the speed and armature current of the motor if the flux per pole is reduced to 75 per cent of its initial value, the total torque remaining unaltered. (10)

Q9. (a) Explain what is meant by phase difference between voltage and current values. (6)
(b) An inductance coil has a resistance of 19.5Ω and when connected to a 220V, 50Hz supply, the current passing is 10A. Find the inductance of the coil. (10)