Larsen & Toubro Limited Electrical Engineer Interview Questions and Answers

An induction motor works by using electromagnetic induction to generate a rotating magnetic field.

• An induction motor consists of a stator and a rotor.

• The stator has a set of windings that are connected to an AC power source.

• When the AC power is applied, it creates a rotating magnetic field in the stator.

• The rotating magnetic field induces currents in the rotor windings, which in turn creates a magnetic field in the rot...read more

Answering generator sizing calculations for Electrical Engineer interview.

• Generator sizing calculations involve determining the power requirements of the load to be supplied by the generator.

• Factors to consider include the type of load, the starting current, and the power factor.

• The generator should be sized to handle the maximum expected load, with some margin for safety.

• Generator sizing calculations can be done manua...read more

Load list is a document that lists all the electrical loads in a building or facility.

• It includes details such as the name of the load, its location, power rating, and voltage requirements.

• Load list is used to determine the total power demand of the building and to design the electrical system accordingly.

• It is also used for maintenance and troubleshooting purposes.

• Examples of loads that may be included in a load list ...read more

Differential relays are typically located at the ends of a protected zone.

• Differential relays are used to detect faults within a protected zone

• They compare the current entering and leaving the zone

• If there is a difference, it indicates a fault

• The relay is typically located at the end of the zone closest to the source

• This allows for the quickest detection and isolation of faults

Resolved a critical power distribution issue that improved system reliability and reduced downtime significantly.

• Identified a recurring issue with voltage fluctuations in the power distribution system.

• Conducted a root cause analysis, discovering that outdated transformers were causing inefficiencies.

• Proposed a replacement plan for the transformers, which included cost-benefit analysis and timeline.

• Collaborated with the...read more

I have managed various electrical projects, focusing on design, implementation, and troubleshooting across multiple sectors.

• Designed and implemented a solar power system for a residential building, improving energy efficiency by 30%.

• Led a team in upgrading the electrical infrastructure of a manufacturing plant, reducing downtime by 15%.

• Conducted troubleshooting and maintenance for high-voltage equipment, ensuring compl...read more

Criteria for evaluating cable thickness and length in electrical engineering.

• Consider the current carrying capacity of the cable

• Evaluate the voltage drop over the length of the cable

• Take into account the environmental conditions where the cable will be installed

• Check the insulation material and its thickness

• Ensure the cable length is sufficient for the intended application

The number of workmen needed depends on the size and complexity of the traywork, cable vault, and piperack.

• The number of workmen needed for a 100km traywork in 20 days will vary based on factors such as terrain, weather conditions, and equipment availability.

• For a cable vault, the number of workmen required will depend on the size of the vault, the type of cables being installed, and any specific safety regulations tha...read more

Earthing procedures involve connecting electrical systems to the ground to prevent electric shock and ensure safety. Earthgrid is a network of interconnected grounding systems.

• Earthing procedures involve connecting electrical systems to the ground using conductors like copper rods or plates.

• The purpose of earthing is to prevent electric shock by providing a path for fault currents to flow safely into the ground.

• Earthgr...read more

Cable dressing is the process of organizing and securing cables in a neat and efficient manner to improve safety and aesthetics.

• Cable dressing involves arranging cables in a way that minimizes interference and maximizes airflow.

• It helps in identifying and tracing cables easily for maintenance or troubleshooting.

• Proper cable dressing can prevent cable damage and reduce the risk of electrical hazards.

• Examples of cable dr...read more

Choosing the right cable depends on load type, voltage, distance, and environmental factors.

• Consider the load type: for motors, use armored cables; for lighting, use PVC insulated cables.

• Voltage rating is crucial: for high voltage equipment, select cables rated above the operating voltage.

• Distance affects voltage drop: for long runs, use larger gauge cables to minimize losses.

• Environmental conditions matter: in wet are...read more

My current payment is $80,000 annually before taxes and $65,000 after taxes.

• My current annual salary is $80,000 before taxes

• After taxes, my take-home pay is $65,000

• I receive a monthly salary of $6,666.67 before taxes

Provide details about a specific topic or project.

• Include background information

• Explain the purpose or goal

• Discuss the methods or techniques used

• Present the results or outcomes

• Highlight any challenges faced and how they were overcome