3rd 6th month 2

Question 1

as air flows in a pipe and the diameter decreases, the speed of the air ___ and the pressure _____

Answer 1

increases

decreases

Question 2

reciprocating air compressor intake valves are forced open by

Answer 2

atmospheric pressure

Question 3

the impeller (blower) compressor delivers air at

Answer 3

high volume and low pressure

Question 4

method of decreasing output of a centrifugal compressor is _____ but this will not work if the reduction is _____

Answer 4

speed reduction

too large

Question 5

the greater pressure losses occur because airflow at ____ is affected by ____

Answer 5

low pressure

greater friction

Question 6

when disconnecting high pressure lines be careful of

Answer 6

blowing of dust or chips

Question 7

to guard against excessive pressure on the secondary side of a pressure regulator is to us a

Answer 7

pressure regulator with a built in relief valveq

Question 8

hoursepower output wanes with the _____ of the shaft

Answer 8

speed and torque

Question 9

highest power of output of a pneumatic motor occurs at

Answer 9

meduem speed

Question 10

unloading the compressor

Answer 10

run without delivering air

Question 11

single stage compressor are capable of delivering up to

Answer 11

50psi

Question 12

screw compressors operate at speeds between

Answer 12

3000 and 12000 rpms

Question 13

two disadvantages of centrifugal compressors

Answer 13

more horse power

higher speeds

Question 14

as air is compressed, moisture capacity is

Answer 14

decreased

Question 15

water cooled after coolers are typically used with ______ compressors that run ___

Answer 15

large capacity

10 or more hours a day

Question 16

the operation of an internal seperator depends on a

Answer 16

rapid change in direction of airflow

Question 17

a fine line lubricator is for ______ and ____ range lines

Answer 17

intermittent

long

Question 18

what type of turbine has variable vane design and can be used for both pumping and generating

Answer 18

deriaz

Question 19

the minimum velocity of water in a power canal to prevent the deposit of silt is

Answer 19

2-3ft per sec

Question 20

to prevent negative pressure in a penstock where pipe is being used, what is installed in the pipline

Answer 20

airvents

Question 21

always use pipe joint compound for

Answer 21

npt threaded pipe

Question 22

valve that has five connecting ports, two are exhaust ports

Answer 22

four way valve

Question 23

the only purpose of a pressure relief valve is to

Answer 23

protect the system from damage

Question 24

an increase in pressure on the secondary side of a pressure regulating valve _______ the valve

Answer 24

slightly closes

Question 25

exhaust flow metering valve limits

Answer 25

return stroke speed

Question 26

the highest torque a pneumatic motor can exert on a load is its

Answer 26

stalling torque

Question 27

a well designed protective relay system should provide 3 basic operational caracteristics

Answer 27

reliability
selectivity
speed

Question 28

the circuit diagram usually gives the following 3 items of info about current and voltage, eliminate 1:
location
direction
polarity
magnitude

Answer 28

magnitude

Question 29

the ground and neutral point on a 3 phase system are the same point. t/f

Answer 29

false

Question 30

Polyphase rotating equipment may be protected against single phase operation by using a

Answer 30

phase-balance relay