Jindal Aluminium Sr.Engineer Mechanical Maintenance Interview Questions and Answers for Experienced

DOL (Direct-On-Line) and star delta are two different wiring schemes used in electrical engineering for starting induction motors.

• DOL wiring directly connects the motor to the power supply for starting, while star delta wiring initially starts the motor in star configuration and then switches to delta configuration for running.

• DOL wiring is simpler and cheaper but causes high starting current, while star delta wiring r...read more

Refractories are materials that can withstand high temperatures and are used in furnaces, kilns, and other high-temperature applications.

• Refractories are made from materials such as clay, silica, alumina, and magnesia.

• They are used to line furnaces, kilns, and other high-temperature equipment to protect them from heat and corrosion.

• Refractories are classified based on their chemical composition, physical properties, an...read more

There are three types of refractories: acidic, basic, and neutral.

• Refractories are materials that can withstand high temperatures and are used in furnaces, kilns, and other high-temperature applications.

• Acidic refractories are made of materials like silica and alumina and are used in acidic environments.

• Basic refractories are made of materials like magnesia and dolomite and are used in basic environments.

• Neutral refrac...read more

Turbine generator work involves converting mechanical energy into electrical energy using steam or water.

• Turbine generators use steam or water to rotate a turbine connected to a generator

• The rotating turbine spins magnets inside the generator, creating an electric current

• The electric current is then transmitted through power lines for use in homes and industries

Causes of hot bearings include lack of lubrication, overloading, misalignment, and contamination.

• Lack of lubrication: Insufficient or degraded lubricant can cause increased friction and heat.

• Overloading: Excessive load on the bearing can lead to overheating.

• Misalignment: Improper alignment of the bearing can cause it to operate under stress and generate heat.

• Contamination: Foreign particles or debris in the bearing can

Over-heating of Commutator in a DC motor can be caused by factors like excessive current, poor ventilation, dirty environment, and worn-out brushes.

• Excessive current flowing through the motor can cause the commutator to overheat.

• Poor ventilation around the motor can lead to inadequate cooling, resulting in overheating.

• A dirty environment can cause dust and debris to accumulate on the commutator, hindering heat dissipat...read more

The shunt motor will run at dangerously high speeds and may get damaged.

• The motor will run at its no-load speed, which is much higher than its rated speed.

• This can lead to overheating and mechanical stress on the motor components.

• The motor may get damaged or fail prematurely if directly connected to the supply line.

Density of slurry is the mass of the slurry per unit volume.

• Density of slurry is typically measured in kg/m^3 or lb/ft^3.

• It is calculated by dividing the mass of the slurry by its volume.

• The density of slurry can vary depending on the concentration of solids in the liquid.

• For example, a slurry with a high concentration of solids will have a higher density.

SPL stands for Sound Pressure Level and SEL stands for Sound Exposure Level.

• SPL is a measure of sound intensity relative to a reference level.

• SEL is a measure of sound exposure over a period of time, typically in decibels.

• Both SPL and SEL are commonly used in the field of acoustics and noise control.

The red area typically refers to a section or region that is highlighted or marked in the color red.

• Red area can indicate danger or warning.

• In engineering, red areas on diagrams or blueprints may signify areas of high risk or critical components.

• Examples: red area on a map indicating a fire hazard zone, red area on a circuit diagram highlighting a high voltage section.

A relief valve is a safety device used to control or limit pressure in a system by releasing excess pressure.

• Relief valves are commonly used in steam boilers, pressure vessels, and pipelines.

• They are designed to open and release excess pressure when the pressure inside the system exceeds a certain limit.

• This helps prevent damage to the system and ensures the safety of personnel working with the system.

• Relief valves can...read more

A process flow diagram of a plate rolling mill

• Raw materials are loaded onto the mill

• The plate is rolled to the desired thickness and length

• The plate is then cooled and cut to size

• The finished product is inspected for quality

• The product is then packaged and shipped to customers