Nesma Electric Interview Questions and Answers

Rectifier, types of motor, difference between servo motor and induction motor

• Rectifier is an electrical device that converts alternating current (AC) to direct current (DC)

• Types of motors include DC motors, AC motors, servo motors, and induction motors

• Servo motors are used in applications that require precise control of position, velocity, and acceleration

• Induction motors are commonly used in industrial applications due to their robustness and simplicity

• Difference between ser...read more

A transformer is an electrical device that transfers electrical energy from one circuit to another through electromagnetic induction.

• Transformers are used to either step up or step down voltage levels.

• Step down transformers decrease voltage levels, while step up transformers increase voltage levels.

• Types of transformers include power transformers, distribution transformers, isolation transformers, autotransformers, and instrument transformers.

• Power transformers are used in po...read more

PLC stands for Programmable Logic Controller. It is an industrial computer used to automate processes.

• PLCs are used to control and monitor industrial processes such as assembly lines, power plants, and water treatment facilities.

• They are programmed using ladder logic or other programming languages.

• PLCs can be used to control various types of equipment such as motors, valves, and sensors.

• They are designed to operate in harsh environments and can withstand extreme temperatures,...read more

Stress is the force applied to a material, while strain is the resulting deformation or change in shape.

• Stress is a measure of the internal resistance of a material to deformation under an applied force.

• Strain is the measure of the deformation or displacement of material in response to stress.

• Stress is typically measured in units of force per unit area (such as N/m^2 or Pa), while strain is dimensionless.

• Stress can cause strain in a material, leading to changes in its shape o...read more

A piston is a component in an engine that moves up and down in a cylinder, converting pressure into mechanical motion. A crankshaft is a rotating shaft that converts reciprocating motion into rotational motion. A bearing is a device that supports and reduces friction between moving parts.

• Piston: Moves up and down in a cylinder, sealed by piston rings. Transfers force from expanding gases to the crankshaft.

• Crankshaft: Converts the reciprocating motion of the piston into rotati...read more

Diesel engines and petrol engines differ in their fuel type, ignition process, and efficiency.

• Fuel type: Diesel engines use diesel fuel, while petrol engines use gasoline.

• Ignition process: Diesel engines use compression ignition, while petrol engines use spark ignition.

• Efficiency: Diesel engines are generally more fuel-efficient than petrol engines.

• Examples: Cars, trucks, and buses often use petrol engines, while heavy-duty vehicles and generators commonly use diesel engines.

An encoder is a device used to convert motion or position into a coded signal.

• Encoders are commonly used in robotics, CNC machines, and industrial automation.

• They can be either absolute or incremental, with absolute encoders providing a unique code for each position and incremental encoders providing a relative change in position.

• Encoders can be rotary or linear, depending on the type of motion being measured.

• They are often used in closed-loop control systems to provide feedb...read more

Mechanical properties of materials refer to their ability to withstand applied forces without failure.

• Mechanical properties include strength, hardness, toughness, ductility, and elasticity.

• Strength is the ability of a material to withstand an applied force without failure.

• Hardness is the resistance of a material to deformation or scratching.

• Toughness is the ability of a material to absorb energy and plastically deform without fracturing.

• Ductility is the ability of a material ...read more