Etisalat Interview Questions and Answers

Sensors are devices that detect and respond to physical stimuli and convert them into electrical signals.

• There are various types of sensors such as temperature sensors, pressure sensors, proximity sensors, motion sensors, light sensors, etc.

• Temperature sensors measure the temperature of an object or environment and include thermocouples, RTDs, and thermistors.

• Pressure sensors measure the pressure of gases or liquids and include piezoresistive, capacitive, and piezoelectric se...read more

PLC stands for Programmable Logic Controller, which is a digital computer used for automation of industrial processes.

• PLC is used to control and monitor various industrial processes.

• It is programmed using ladder logic or other programming languages.

• PLC can be used in various industries such as manufacturing, automotive, and food processing.

• It can control machines, motors, and other equipment.

• PLC can be connected to sensors and other devices to gather data and make decisions b...read more

DOL starter is a type of motor starter used to start and stop motors.

• DOL stands for Direct-On-Line.

• It is used for motors with low to medium power ratings.

• It consists of a contactor, overload relay, and start and stop buttons.

• When the start button is pressed, the contactor closes and the motor starts.

• When the stop button is pressed, the contactor opens and the motor stops.

• It provides full voltage to the motor during starting, which can cause high starting currents.

• It is not su...read more

There are various types of motors and starts used in industries.

• Types of motors: AC motors, DC motors, Servo motors, Stepper motors

• Types of starts: Direct-on-line (DOL) start, Star-delta start, Soft starter, Variable frequency drive (VFD) start

• AC motors are widely used in industries due to their low cost and easy maintenance

• DC motors are used in applications where precise speed control is required

• Servo motors are used in robotics and automation

• Stepper motors are used in appli...read more

VFD stands for Variable Frequency Drive. It is an electronic device that controls the speed of an AC motor.

• VFD is used to save energy and improve motor control.

• It can adjust the frequency and voltage supplied to the motor.

• VFDs are commonly used in HVAC systems, pumps, and fans.

• They can also be used in industrial applications such as conveyor belts and machine tools.

• VFDs can provide soft start and stop capabilities, reducing wear and tear on the motor.

• They can also provide ove...read more