Industrial Electrical Systems 2025

(a) In a single line diagram, the representation of wiring and devices is done using:

1. Photographs
2. Standard electrical symbols
3. Graphs
4. Mathematical equations

(b) The inverse time-current characteristic is a property of:

1. Transformer
2. Isolator
3. Circuit breaker
4. Contactor

(c) Luminous flux is measured in:

1. Lux
2. Lumen
3. Watt
4. Candela

(d) The lamp which operates on the principle of electroluminescence is:

1. Incandescent lamp
2. Mercury vapor lamp
3. Fluorescent lamp
4. LED lamp

(e) MCBs protect electrical circuits primarily from:

1. Earth faults
2. Thermal effects
3. Under-voltage
4. Overcurrent and short circuits

(f) For earthing in residences, which of the following value is considered safe for earth resistance?

1. 1-5 ohms
2. 20-30 ohms
3. 10-15 ohms
4. 50 ohms

(g) Which panel controls and distributes main supply to motors?

1. PCC
2. Control panel
3. MCC
4. Lighting panel

(h) Which of the following is not a component of a battery bank?

1. Battery cells
2. Alternator
3. Intercell connectors
4. Vent plugs

(i) Uninterruptible Power Supply (UPS) provides protection mainly against:

1. Lightning
2. Power failure and voltage fluctuations
3. Mechanical overloads
4. Earth faults

(j) Lightning protection in industries is provided by:

1. Fuses
2. Surge arresters and earthing
3. Relays
4. Circuit Breaker

(a) Draw a labeled single line diagram (SLD) for a small residential wiring system, indicating all major components and protection devices.

(b) Compare the construction, working principle, and application areas of MCB, MCCB, and ELCB. Where would you recommend the use of each device?

(a) Explain the procedure for selecting the proper gauge of wire and rating of main switch for a commercial building with calculation steps.

(b) Define and explain the significance of: luminous flux, lumen, lux, utilization factor, depreciation factor, and glare in lighting design.

(a) A classroom has a floor area of 60 m² and requires an average illumination of 200 lux. If each fluorescent lamp gives 1200 lumens and the utilization factor is 0.6, calculate the number of lamps required, assuming a maintenance factor of 0.8.

(b) Using lamps of 1000 lumens each and a utilization factor of 0.7, how many lamps are needed for a room requiring 4200 effective lumens?

(a) Explain the general rules and guidelines used for the installation of the residential wiring systems.

(b) What are the general I.E. rules for wiring installation?

(a) Write the causes for low power factor in power system. Give the solution for improvement of power factor.

(b) What are the three types of wiring connection in commercial wiring?

(a) Explain the function of an industrial substation in an electrical system. How are monitoring and control operations carried out in substations?

(b) Discuss the industrial loads with the help of examples. How are these different from residential loads? Explain.

(a) Explain the functioning of a UPS system with block diagram. What are the main considerations in selecting and sizing a UPS for sensitive equipment?

(b) Outline the procedure for sizing a battery bank for emergency backup in an industrial set-up.

(a) Discuss the role and advantages of SCADA systems in industrial automation and power distribution monitoring.

(b) What are the basic components of a PLC-based control system? Draw a block diagram and explain the function of each part.