Question 1

What is the main function of a compressed-air unit in a pneumatic system?

Accepted Answer

To produce pressurized air

Answer

To generate electrical power

Answer

To filter coolant

Answer

To store hydraulic fluid

Question 2

What is a characteristic of a portable compressed-air unit?

Accepted Answer

It can be easily moved from one location to another

Answer

It is permanently installed

Answer

It requires manual pumping

Answer

It has a larger compressor

Question 3

What distinguishes a central air supply from a portable unit?

Accepted Answer

It has a permanently mounted compressor and air lines

Answer

It is used only in emergency situations

Answer

It uses manual valves

Answer

It can be carried easily

Question 4

Which of the following is not a function of compressed-air units?

Accepted Answer

Producing electricity

Answer

Controlling air temperature

Answer

Storing conditioned air

Answer

Removing water vapor

Question 5

What drives the compressor in a compressed-air unit?

Accepted Answer

Prime mover

Answer

Safety valve

Answer

Dryer

Answer

Receiver

Question 6

Which is the most common type of prime mover?

Accepted Answer

Electric motor

Answer

Gasoline engine

Answer

Solar panel

Answer

Hand crank

Question 7

What connects the prime mover to the compressor?

Accepted Answer

Mechanical coupling

Answer

Cooling line

Answer

Insulated pipe

Answer

Filter trap

Question 8

What determines the type of coupling used between the prime mover and compressor?

Accepted Answer

Speed, load, and shaft misalignment

Answer

Material color

Answer

Air temperature

Answer

Fuel type

Question 9

What is the role of the compressor in the unit?

Accepted Answer

Generate compressed air

Answer

Store high-voltage energy

Answer

Filter out particulates

Answer

Remove oil from the air

Question 10

What is the purpose of the receiver in a compressed-air unit?

Accepted Answer

To store compressed air

Answer

To recharge batteries

Answer

To generate heat

Answer

To mix air and fuel

Question 11

How does the receiver help with air quality?

Accepted Answer

It assists in cooling and removing water vapor

Answer

It sprays perfume into the air

Answer

It increases humidity

Answer

It adds oil to the system

Question 12

What controls maximum air pressure in a compressed-air unit?

Accepted Answer

Capacity-limiting system

Answer

Relief hose

Answer

Water cooler

Answer

Manual pressure gauge

Question 13

What device starts and stops the prime mover at set pressures?

Accepted Answer

Electrically operated pressure switch

Answer

Air dryer

Answer

Mechanical flywheel

Answer

Automatic relief tube

Question 14

What happens if the pressure switch fails?

Accepted Answer

Safety valve opens to vent pressure

Answer

The system overloads and stops

Answer

The compressor shuts off permanently

Answer

The air lines freeze

Question 15

What component removes dirt from incoming air?

Accepted Answer

Air filter

Answer

Receiver

Answer

Relief valve

Answer

Crankshaft

Question 16

What ensures clean, cool, and dry air delivery?

Accepted Answer

Coolers and dryers

Answer

Safety switches

Answer

Air tanks

Answer

Power converters

Question 17

What forms the pumping chambers in a basic compressor?

Accepted Answer

Space above pistons

Answer

Receiver tank

Answer

Oil sump

Answer

Crankshaft housing

Question 18

When do the inlet valves open in compressor operation?

Accepted Answer

As pistons move down

Answer

When the crankshaft stops

Answer

During air discharge

Answer

As the pressure increases

Question 19

When do the outlet valves open in compressor operation?

Accepted Answer

As pistons move up

Answer

After cooling

Answer

When no air is needed

Answer

As pistons move down

Question 20

What is the correct sequence of the three compressor operation phases?

Accepted Answer

Air intake, Air compression, Air discharge

Answer

Air cooling, Air storage, Air release

Answer

Air storage, Air discharge, Air intake

Answer

Air discharge, Air intake, Air combustion

Question 21

What happens during the air intake phase?

Accepted Answer

Piston moves down, chamber volume increases, air enters

Answer

Air exits through outlet valve

Answer

Pressure switch activates

Answer

Piston moves up, chamber compresses air

Question 22

What condition allows the most air to enter during intake?

Accepted Answer

Chamber pressure close to atmospheric pressure

Answer

Chamber at minimum volume

Answer

Piston at top of stroke

Answer

High receiver pressure

Question 23

What initiates the compression phase?

Accepted Answer

Piston begins to move upward

Answer

Filter gets clogged

Answer

Crankshaft stops rotating

Answer

Air temperature drops

Question 24

What indicates energy conversion in compression?

Accepted Answer

Increased pressure in chamber

Answer

Noise level from compressor

Answer

Air velocity through filter

Answer

Decrease in electrical current

Question 25

When does air move into the receiver from the pumping chamber?

Accepted Answer

When chamber pressure exceeds receiver pressure

Answer

When piston is fully down

Answer

When pressure switch is off

Answer

When air is too hot

Question 26

When system pressure is low, when does air transfer occur?

Accepted Answer

Early in the compression stroke

Answer

At maximum piston height

Answer

During piston intake

Answer

Only after cooling

Question 27

What affects the response of a compressor to system demands?

Accepted Answer

Pumping chamber size, operating speed, pressure & volume needed

Answer

Safety valve rating, pipe insulation, cylinder color

Answer

Air temperature, filter type, moisture content

Answer

Voltage of motor, color of housing, brand of compressor

Question 28

What does compressor 'displacement' refer to?

Accepted Answer

Volume of air displaced per unit time

Answer

Diameter of piston rod

Answer

Distance between workstations

Answer

Amount of oil in filter

Question 29

What are positive-displacement compressors known for?

Accepted Answer

Mechanically reducing air chamber volume

Answer

Using static pressure only

Answer

Increasing air temperature

Answer

Spinning impellers at high speed

Question 30

Which of the following is a positive-displacement compressor?

Accepted Answer

Reciprocating

Answer

Centrifugal

Answer

Dynamic

Answer

Axial-flow

Question 31

How do non-positive displacement compressors operate?

Accepted Answer

By rotating impellers or vanes at high speed

Answer

By freezing air

Answer

Through piston compression

Answer

By manually compressing air

Question 32

Which is an example of a non-positive displacement compressor?

Accepted Answer

Centrifugal compressor

Answer

Sliding vane compressor

Answer

Reciprocating compressor

Answer

Rotary screw compressor

Question 33

What are the two basic compressor motion classifications?

Accepted Answer

Reciprocating and rotary

Answer

Axial and centrifugal

Answer

Static and dynamic

Answer

Linear and pneumatic

Question 34

What enhances the efficiency of reciprocating compressors?

Accepted Answer

Multiple cylinders and piston designs

Answer

More air filters

Answer

Increased motor temperature

Answer

Reduced crankshaft speed

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