ArcelorMittal Nippon Steel Hvac Technician Interview Questions and Answers

A relay is an electrical device that acts as a switch to control the flow of current in an electrical circuit.

• Relays are used to control high-power devices with low-power signals.

• They consist of an electromagnet and a set of contacts.

• When the electromagnet is energized, it creates a magnetic field that attracts or releases the contacts, allowing or interrupting the flow of current.

• Relays are commonly used in industrial...read more

Reverse forward draw is a control wiring method used in electrical systems to control the direction of rotation of a motor.

• Reverse forward draw is used to control the direction of rotation of a motor.

• It involves the use of a forward contactor and a reverse contactor.

• The control wiring includes connections between the contactors, motor, and power supply.

• By energizing the forward contactor, the motor rotates in one direc...read more

An AC motor is a type of electric motor that operates on alternating current.

• AC motor stands for Alternating Current motor.

• It converts electrical energy into mechanical energy.

• AC motors are commonly used in household appliances, industrial machinery, and vehicles.

• They are more efficient and require less maintenance compared to DC motors.

• Examples of AC motors include induction motors, synchronous motors, and brushless m

AC motors and DC motors differ in their power source, construction, speed control, and applications.

• AC motors run on alternating current, while DC motors run on direct current.

• AC motors are more commonly used in household appliances, industrial machinery, and electric vehicles.

• DC motors are often found in battery-powered devices, such as laptops, electric cars, and robots.

• AC motors have a simpler construction with fewe...read more

MCB stands for Miniature Circuit Breaker.

• MCB is an electrical switch that automatically interrupts the flow of current in an electrical circuit during an overload or short circuit.

• It is a type of circuit breaker that is commonly used in residential and commercial buildings.

• MCBs are designed to protect electrical circuits and appliances from damage caused by excessive current.

• They are compact in size and can be easily i...read more

A timer is a device that measures and controls the passage of time.

• A timer is used to initiate or stop a process at a specific time or after a specific duration.

• Timers can be mechanical or electronic.

• They are commonly used in various applications such as appliances, industrial machinery, and automation systems.

• Examples of timers include kitchen timers, programmable thermostats, and countdown timers in sports events.

VFD stands for Variable Frequency Drive.

• VFD is an electronic device used to control the speed and torque of an electric motor.

• It adjusts the frequency and voltage supplied to the motor, allowing for precise control of motor speed.

• VFDs are commonly used in industrial applications to save energy, improve motor performance, and enable soft starting and stopping.

• They are also known as AC drives, adjustable speed drives, or...read more

PLC stands for Programmable Logic Controller. It is a digital computer used for automation of electromechanical processes.

• PLC is a specialized computer designed to control industrial processes.

• It uses a programmable memory to store instructions and execute them in a sequential manner.

• PLCs are commonly used in manufacturing plants, power stations, and other industrial settings.

• They can be programmed to control various d...read more

An AC motor is a type of electric motor that operates on alternating current.

• AC motor stands for alternating current motor.

• It converts electrical energy into mechanical energy.

• AC motors are commonly used in household appliances, industrial machinery, and vehicles.

• They are more efficient and require less maintenance compared to DC motors.

• Examples of AC motors include induction motors, synchronous motors, and brushless m

A rectifier is an electrical device that converts alternating current (AC) to direct current (DC).

• Rectifiers are commonly used in power supplies to convert AC voltage to DC voltage.

• They are made up of diodes, which allow current to flow in only one direction.

• Rectifiers can be half-wave or full-wave, depending on the number of diodes used.

• Examples of rectifiers include bridge rectifiers, vacuum tube rectifiers, and soli

A diode is an electronic component that allows current to flow in one direction and blocks it in the opposite direction.

• Diodes are commonly used in rectifier circuits to convert AC to DC.

• They have two terminals: an anode (positive) and a cathode (negative).

• When the voltage across a diode is forward-biased, it allows current to flow.

• When the voltage is reverse-biased, it blocks the current.

• Diodes are often used for volt...read more

PLC stands for Programmable Logic Controller. It is a digital computer used for automation of electromechanical processes.

• PLC is used to control and monitor industrial processes.

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

• PLCs are commonly used in manufacturing, power plants, and transportation systems.

• They can be used to control motors, valves, sensors, and other devices.

• PLCs provide real-time m...read more

A timer is a device or software that measures and controls the passage of time.

• A timer can be a physical device with buttons and a display, or it can be a software program on a computer or smartphone.

• Timers are commonly used in various applications such as cooking, sports, and industrial processes.

• They can be set to count down from a specific time or count up from zero.

• Some timers have additional features like alarms, ...read more

The point angle of scriber is the angle between the two cutting edges of the scriber.

• The point angle is typically between 30 and 60 degrees.

• It affects the sharpness and durability of the scriber.

• A larger point angle will result in a stronger but less sharp scriber.

• A smaller point angle will result in a sharper but less durable scriber.

The point angle of a centre punch is typically 90 degrees.

• The point angle is the angle between the two sides of the punch tip.

• A 90 degree point angle is the most common and versatile for general use.

• Different point angles can be used for specific applications, such as 60 degrees for softer materials.

• The point angle affects the size and shape of the indentation made by the punch.

HVAC maintenance work involves regular inspections, cleaning, and repairs to ensure efficient and safe operation of heating, ventilation, and air conditioning systems.

• Regularly inspect HVAC systems to identify any potential issues

• Clean and replace filters, coils, and other components as needed

• Perform routine maintenance tasks such as lubricating motors and checking electrical connections

• Repair or replace faulty compone...read more

HVAC maintenance work involves regular inspections, cleaning, and repairs to ensure efficient and safe operation of HVAC systems.

• Regular inspections of HVAC systems to identify potential issues before they become major problems

• Cleaning of HVAC components such as filters, coils, and ducts to improve system efficiency and indoor air quality

• Repairs and replacements of faulty components to prevent system breakdowns and ens...read more

MCB stands for Miniature Circuit Breaker, which is an electrical switch designed to protect electrical circuits from damage caused by overload or short circuit.

• MCB is a type of circuit breaker that automatically switches off the electrical circuit when it detects an overload or short circuit.

• It is commonly used in residential and commercial buildings to protect electrical appliances and wiring.

• MCBs have a trip mechanis...read more

There are two main types of stators: salient pole stators and non-salient pole stators.

• Salient pole stators have protruding poles, which are commonly used in hydroelectric generators.

• Non-salient pole stators have a smooth cylindrical shape and are typically used in gas and steam turbines.

• Other types of stators include wound stators and squirrel cage stators.

A u dol diagram is a type of electrical diagram used to represent a three-phase transformer connection.

• A u dol diagram consists of three sets of windings connected in a U shape, with the primary winding connected to the supply and the secondary winding connected to the load.

• The diagram shows the connections of the primary and secondary windings, as well as the neutral point if applicable.

• U dol diagrams are commonly use...read more

There are two main types of motors: AC motors and DC motors.

• AC motors: Alternating current motors that are commonly used in household appliances and industrial applications.

• DC motors: Direct current motors that are often used in small household devices, electric vehicles, and robotics.