ISS Facility Services Senior Engineer- Maintenance Interview Questions and Answers

A generator is a device that converts mechanical energy into electrical energy.

• Generators are commonly used to provide backup power during electrical outages.

• They work on the principle of electromagnetic induction.

• Generators can be powered by various sources such as gasoline, diesel, natural gas, or renewable energy.

• They are used in various applications including residential, commercial, and industrial sectors.

• Examples...read more

In a power failure situation, it is important to have a plan in place to manage the situation effectively.

• Ensure safety by turning off electrical equipment and appliances

• Check the circuit breaker or fuse box for any tripped breakers or blown fuses

• Use alternative power sources like generators or battery backups

• Prioritize critical systems and equipment for power restoration

• Communicate with relevant stakeholders and keep ...read more

In equipment failure situations, it is important to have a systematic approach to manage the issue.

• Identify the cause of the equipment failure

• Isolate the equipment to prevent further damage

• Notify the appropriate personnel or department

• Develop a plan to repair or replace the equipment

• Coordinate with suppliers or vendors for necessary parts or replacements

• Implement the repair or replacement plan

• Test and verify the functi...read more

UPS stands for Uninterruptible Power Supply.

• UPS is a device that provides emergency power to a load when the input power source fails.

• It is commonly used to protect sensitive electrical equipment from power disruptions or outages.

• UPS systems can be classified into three types: offline/standby, line-interactive, and online/double-conversion.

• Examples of UPS applications include data centers, hospitals, telecommunications

To connect UPS batteries, follow these steps: 1. Identify the positive and negative terminals. 2. Connect the positive terminal of one battery to the negative terminal of the next battery. 3. Repeat until all batteries are connected in series or parallel.

• Identify the positive and negative terminals of the batteries

• Connect the positive terminal of one battery to the negative terminal of the next battery

• Repeat the connec...read more

The battery voltage during charging times varies depending on the type of battery and charging method.

• The battery voltage during charging times can range from 2 volts to 48 volts.

• For example, a typical lead-acid battery used in automotive applications has a charging voltage of around 14.4 volts.

• On the other hand, lithium-ion batteries used in smartphones and laptops have a charging voltage of around 3.7 volts per cell.

• ...read more

The battery bolt in discharge times refers to the duration it takes for a battery to fully discharge.

• Battery bolt in discharge times is a measure of how long a battery can power a device before it is completely drained.

• It is important to consider battery discharge times when designing electrical systems to ensure uninterrupted power supply.

• Factors such as battery capacity, load, and efficiency affect the discharge time...read more

The A check in a generator refers to a routine inspection and maintenance procedure.

• The A check involves inspecting and testing various components of the generator.

• It includes checking the fuel system, lubrication system, cooling system, and electrical connections.

• During the A check, the generator's performance is evaluated and any necessary repairs or adjustments are made.

• Examples of tasks performed during an A check ...read more

B check in generator refers to a comprehensive inspection and maintenance procedure to ensure the generator's optimal performance.

• B check involves a thorough examination of the generator's components, systems, and controls.

• It includes inspecting and cleaning the air filters, fuel system, cooling system, and exhaust system.

• Electrical connections, wiring, and insulation are checked for any signs of damage or wear.

• The gen...read more

In a fire situation, it is important to prioritize safety and follow established protocols.

• Stay calm and alert

• Evacuate the area immediately

• Activate the fire alarm and alert others

• Call emergency services

• Use fire extinguishers if safe to do so

• Follow evacuation routes and assembly points

• Do not use elevators

• Assist others if possible

• Do not re-enter the area until it is declared safe

To find out a worn bearing number, inspect the bearing for visible signs of wear and refer to the bearing manufacturer's documentation.

• Inspect the bearing for signs of wear such as discoloration, pitting, or scoring on the bearing surface.

• Check for excessive play or looseness in the bearing when it is rotated.

• Refer to the bearing manufacturer's documentation or catalog to identify the bearing number based on its physic...read more

Seal numbers can be found on the seal itself or in the equipment manual.

• Check the seal itself for any visible numbers or markings.

• Refer to the equipment manual for information on the seal.

• Contact the manufacturer or supplier for assistance in identifying the seal number.

Types of pumps include centrifugal, positive displacement, axial flow, and jet pumps.

• Centrifugal pumps use a rotating impeller to create a flow of fluid.

• Positive displacement pumps move fluid by trapping a fixed amount and forcing it through the system.

• Axial flow pumps move fluid parallel to the axis of rotation.

• Jet pumps use a jet of high-pressure fluid to create a low-pressure area and move fluid.

• Other types of pumps...read more

Gear boxes are used to transmit power and torque from one rotating shaft to another. There are several types of gear boxes.

• Manual transmission

• Automatic transmission

• Semi-automatic transmission

• Continuously variable transmission (CVT)

• Dual-clutch transmission (DCT)

• Epicyclic gear train

• Planetary gear train

• Worm gear box

• Bevel gear box

• Helical gear box

Pumps can be classified based on their working principle, design, and application.

• Based on working principle: centrifugal, positive displacement, and jet pumps

• Based on design: single-stage, multi-stage, axial, and mixed flow pumps

• Based on application: water, chemical, slurry, and oil pumps

• Other classifications: reciprocating, rotary, and diaphragm pumps

Mechanical seals are used to prevent leakage in rotating equipment. They can be classified into various types based on their design and application.

• Types of mechanical seals include pusher seals, non-pusher seals, cartridge seals, and split seals.

• Pusher seals use springs to maintain contact between the seal faces.

• Non-pusher seals rely on the pressure of the fluid being sealed to maintain contact.

• Cartridge seals are pre...read more

Maintenance of compressors involves regular inspection, cleaning, lubrication, and replacement of worn-out parts.

• Regular inspection of compressor components such as valves, pistons, and bearings

• Cleaning of air filters, coolers, and intercoolers to prevent clogging

• Lubrication of moving parts to reduce friction and wear

• Replacement of worn-out parts such as belts, hoses, and seals

• Monitoring of compressor performance and a

Pneumatic cylinders use compressed air while hydraulic cylinders use pressurized fluid to generate force.

• Pneumatic cylinders are lighter and cheaper than hydraulic cylinders.

• Hydraulic cylinders can generate more force than pneumatic cylinders.

• Single-acting, double-acting, and telescoping are common types of hydraulic cylinders.

• Diaphragm, bellows, and rodless are common types of pneumatic cylinders.

Solenoid valves are used to control the flow of fluids or gases in mechanical systems.

• Solenoid valves are commonly used in hydraulic and pneumatic systems.

• They can be used to control the flow of water, oil, gas, or air.

• They are often used in HVAC systems to control the flow of refrigerant.

• Solenoid valves can be controlled by electrical signals to open or close the valve.

• They are also used in automatic irrigation system...read more

There are various types of oils used in mechanical maintenance, each with different grades and purposes.

• Mineral oils: Derived from crude oil and commonly used in engines and machinery.

• Synthetic oils: Man-made oils with superior performance and stability, often used in high-performance engines.

• Semi-synthetic oils: Blend of mineral and synthetic oils, offering a balance between performance and cost.

• Multi-grade oils: Desi...read more

A torque spanner is a tool used to apply a specific amount of torque to fasteners.

• A torque spanner is also known as a torque wrench.

• It is commonly used in mechanical maintenance to ensure proper tightening of bolts and nuts.

• Torque spanners have a calibrated scale or digital display to set the desired torque value.

• They provide a clicking sound or visual indicator when the set torque is reached.

• Different types of torque ...read more

Alignment of pump and motor involves ensuring proper positioning and parallelism to optimize performance and prevent damage.

• Start by checking the alignment specifications provided by the pump and motor manufacturers.

• Use alignment tools such as dial indicators, laser alignment systems, or reverse indicator method.

• Ensure the pump and motor shafts are clean and free from any debris or damage.

• Check and adjust the motor and...read more

The purpose of a gear box is to transmit and control power between the engine and the wheels or other driven components.

• Transmits power from the engine to the wheels or other driven components

• Provides torque multiplication and speed reduction

• Allows for the selection of different gear ratios to optimize performance

• Enables the vehicle to operate at different speeds and handle various loads

• Protects the engine and drivetra

An air circuit breaker is an electrical device that provides protection against overcurrents by using air as the medium to extinguish the arc.

• Air circuit breakers work on the principle of thermal and magnetic tripping.

• When an overcurrent flows through the circuit, the bimetallic strip in the breaker heats up and bends, causing the contacts to open.

• The arc generated during the opening of contacts is extinguished by the ...read more

Losses in transformer refer to the energy lost in the form of heat during the process of transforming voltage.

• There are two types of losses in transformers: copper losses and iron losses.

• Copper losses occur due to the resistance of the wire used in the transformer's windings.

• Iron losses occur due to the magnetic properties of the transformer's core material.

• Copper losses can be reduced by using thicker wire or increasi...read more

UPS system ensures uninterrupted power supply during power outages.

• UPS stands for Uninterruptible Power Supply.

• It provides backup power to critical equipment during power outages.

• UPS systems can be of different types such as online, offline, and line-interactive.

• UPS systems are commonly used in data centers, hospitals, and other critical facilities.

UPS provides backup power during power outages while stabilizer maintains a constant voltage output.

• UPS stands for Uninterruptible Power Supply and provides backup power during power outages.

• Stabilizer maintains a constant voltage output and protects electrical equipment from voltage fluctuations.

• UPS is used for critical equipment like servers, medical equipment, etc. while stabilizer is used for household appliances l

Preventive maintenance in electrical systems involves regular inspections, testing, and servicing to prevent equipment failures and ensure optimal performance.

• Regularly inspect electrical equipment for signs of wear, damage, or overheating.

• Perform routine testing and calibration of electrical systems to identify potential issues before they cause failures.

• Clean and lubricate electrical components to prevent dust buildu...read more