DieselShip's Online Content Library

Q1. a) What are the effects of voltage and frequency changes on transformer functioning? (8)

b) State the various energy losses in transformers. (8)

Q2. a) Distinguish between primary and secondary cells. (4)

b) Explain Internal resistance in a battery. (4)

c) What are the factors affecting internal resistance of a battery. (8)

Q3. a) Explain the working of a Megger with the aid of its internal circuit. (12)

b) What safety measures are taken while using a Megger? (4)

Q4. a) What are the regulations regarding Emergency Generator onboard a cargo ship? (6)

b) Describe the functioning of the emergency generator with the help of a flow chart. (10)

Q5. Write short notes on

a) short circuit protection to Induction motors (8)

b) Overload protection to induction motors (8)

Q6. a) State Ohm's Law. (3)

b) State the limitations of Ohm's Law. (3)

c) If the resistance of a circuit is increased to 3 times and the applied Voltage is halved, what will happen to the circuit current? (10)

Q7. a) What is the difference between EMF and PD of a battery. (6)

b) Calculate the value of I1 in the following circuit. (10)

Q8. Derive the formula for total resistance of a circuit containing 3 resistors in

a) Series (8)

b) Parallel (8)

Q9). a) Define Work, power and efficiency (6)

b) A battery is charged with a constant current of 16 amperes for 11 hours after which time it is considered to be fully charged, its voltage per cell being recorded as 2.2V. Find its ampere hour efficiency if it is

(1) Discharged at a rate of 16 amperes for 10 hours, and

(2) 28 amperes for 4 hours.

In either case discharge was discontinued when the voltage per cell fell to 1.8 V.  (10)