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Fourth Year Millwright 2018 > Important Things to Know > Flashcards

Flashcards in Important Things to Know Deck (127):
1

What is the turbine called that has HP and LP section on separate shaft?

Cross Compound

2

The greatest amount of steam expansion takes place in the?

LP Stage

3

On a reaction turbine the largest blades are in the?

LP Reaction

4

Gas turbines have the highest pressure in the?

Compressor Diffuser

5

Emergency blowdown valves prevent?

Over Pressuring the system

6

what does large diameter steam blading allows for?

High Volume Of Steam

7

What is used to help prevent steam leakage from blade sections?

Shrouding or Shrouds

8

Condenser in the turbine allows steam to perform more work by reducing pressure and?

Less Back Pressure and Recycle Condensate
(Time more efficient)

9

S.A.V is closed by?

Governor

10

Is the overspeed trip mounted on the rotor shaft?

Yes, the bolt has the center of gravity slightly of center of the shaft.

11

What is the first step in starting a gas turbine?

Start button but always follow Manufactures Pre-startup Checks

12

The transition piece connects the inner lines of the power plant combustor to?

Combustion chambers to the turbine and it's duct.

13

What do the moving blades of the turbine consist of?

Disc or Drum Wheels

14

Name for stationary blades?

Nozzles

15

For expansion on turbines sliding dovetails are used?

On rotors for holding reaction blades

16

Spherical bearings used on turbines to?

To compensate for sag on shaft

17

Carbon rings are machined because they?

Fit with very close tolerance

18

On a gasoline carburetor how is the amount of gas delivery controlled?

(Butterfly Valve) Throttle Valve

19

Propane and most carbs used a?

Spray Bar or Nozzles

20

Excessive crankshaft deflection will most likely cause?

Broken crank or fatigue failure

21

What is a micron?

Millionth of a meter
.001 mm

22

What does a magneto ignition system consist of?

*Magnets
*Coil (transformer)
*Spark Plug
*Generates its own power

23

On a 4 stage cycle engine, intake valves opens and closes once, while the crankshaft turns how many degrees?

720°

24

What is artificial respiration when dealing with stationary engines?

Air is forced in to the cylinder

25

What controls the collapse of the primary field of the coil on an electric ignition system?

Transistors

26

Lacing is used in what section of the turbine?

LP Section
(Reaction Blades)

27

Labyrinth seals, seal on the principal of?

Bernoulli Principle
(Knife edges)

28

You start up a piece of equipment after an overhaul you get very high vibration readings, the next step is to?

Shut it down!

29

If you get fluctuations readings when you first start the equipment, wait for readings to settle, this is known as?

Hunting

30

On electric motor, vibration readings are highest in the axial direction, the problem is most likely?

Misalignment

31

Drive belt vibrations amplitude is most likely the highest in-line with?

Direction of belts, because they are pulling on the sheave

32

When taking vibration readings on bearings, the readings should be taken on?

Acceleration and on the Horizontal, vertical, and Axial

33

vibration signals are also known as?

Signatures

34

What is the cause of too low suction lift?

blocked intake

35

If you are taking vibration under 600 rpm use?

Displacement

36

Everything is working the way it should but the input light never comes on?

Bulb burnt-out or the switch is bad

37

How is the suction and discharge valves operated?

by pressure differential of the pump

38

Where does maximum impeller wear widely with semi fluids solids?

Blade tips

39

Two major types of seals used in pumps?

*Static
*Dynamic

40

What is the advantage of wear rings in centrifugal pump?

Increase efficiency prevent recirculation

41

When pumping clear unconcentrated H2O (water) with constant pressure suction side of pump, the stuffing box should work well with what kind of packing?

Solid Packing

42

What is the major reason for using steam throttle valves on large pump?

Direct connected valves require too much force

43

What can be done to modify a reciprocating pump to make it provide a steady and continuous flow?

Add air chambers to outlet side.
(Accumulator)

44

What happens when discharge valve is close on a centrifugal pump?

Pump Slip

45

Gate valves are used as intake and discharge valves because of?

Low Pressure Loss

46

7:1 compression ratio, what is most likely cause of pre-ignition?

Carbon deposits glowing red cause.

47

What is gear mesh frequency of a single gear reduction gear box with an input speed of 3600 rpm and output speed of 1060 with 24T.pinion

1440 hz

48

What is cause of too low suction lift?

Blocked Intake

49

What precautions is to be observed when handling and installing mechanical seals?

keep fingers away from the face of the seal
(any damage with the seal face)

50

Which process is used to seal mechanical seals in an emergency?

Lapping

51

How do you bring coil packing down to exact size?

Roll it with a piece of pipe (or monery) and cut all at once

52

How do you bring coil packing down to exact size?

Roll it with a piece of pipe (or monery) and cut all at once

53

When installing packing rings the joints should be installed?

90° to each other

54

What safety precaution is observed when working on a conveyor to make sure it does not start while you are working on it?

lock and tag (test start button)

55

What is the function of an electrical interlock to enable system shutdown anywhere along the line?

Times the functions

56

What is the probable cause of gravity take-up system that slips on start-up?

Take-up weight to light

57

On a belt conveyor that must be started under full load, what kind of drive should be used?

fluid coupling

58

What chain is best used in abrasive conditions?

mill chain or H-type

59

On an overload conveyors with a compound vertical curve the purpose of the straight section of track is?

to gain the required amount of elevation

60

On a long screw type conveyor sections of screws are joined by?

coupling or dungeon shaft

61

A belt that has a section of it that always runs out of alignment is probably caused by?

Improper or Uneven splice

62

Increasing coefficient of friction on drive pulley without increasing tension, can be accomplished by?

lagging
Snub-pulley= arc of contact

63

Easiest way to change speed at a conveyor?

Change sheave or sprocket diameter

64

On a bucket elevator the length of splice should be?

equal to the width of the belt

65

On pneumatic dust conveyor piping the amount of wear is?

on outside radius of elbow

66

If the diameter of the snub pulley is too small

adjustment will not allow for proper arc of contact

67

Millwright measures electrical pressure with what kind of meter?

volt meter

68

What steps up or down voltage?

transformer

69

Bearings on electric motor lock bearing at what end?

drive end

70

Most common way to reverse direction at DC motor

reverse armature lead

71

Balancing of 3 blade for imbalance of 85°

SIN LAW

72

Who is responsible for providing MSDS

supplier

73

Foot valve

on a centrifugal pump

74

Regenerative pump
How do you know it is one?

The way its mounted and the housing

75

pump curve question

10.7 psi gauge pressure

76

alignment question

Line # 1

77

Which one is the Lowest pressure from first to fourth stage

fourth stage is the lowest pressure

78

gate valves

are used because they are low pressure drop

79

butterfly valve

for lowest pressure drop

80

pressure drop

across both blades in a reaction turbine

81

belt stretch

from overloading

82

driven gear

on picture

83

balancing device on what?

single suction
open closed

84

diaphragm pump

2 pressure limiting valves two diaphragms

85

rotating part

sleeve

86

low npsha

suction is clogged

87

measure clearance

tdc on compression

88

condenser

to increase pressure drop

89

to maintain straigth flow in an axial pump

diffuser vane

90

how to attach long screw conveyor

couplings (dungeon)

91

conveyor that moves cylindrical objects

hour glass

92

cyclone moves material apart by

centrifugal

93

where is the intercooler with a turbo

after the outlet of the turbo

94

most wear in a pipe elbow

outside radius

95

blade on fan

6 or 7 weight on 120 degrees

96

how much ounce weight do you add to balance out

1.7 ounces

97

Phase are the same

Static

98

coil on distributor

primary voltage

99

semi closed impeller

on other picture

100

idlers spaced

for belt sag

101

shaft sleeve used

save on shaft costs

102

Your employer wants you to do computer training in addition of technical training?

Contact LAC
Local Apprenticeship Committee

103

where to put thermo couples

each end of turbine

104

camshaft changes

linear motion to rotational motion

105

holds belts together

Friction

106

how does cooling tower remove heat

By Air

107

Excessive crankshaft deflection

Fatigue Failure or Broken shaft

108

Emergency blow down valves

prevent over pressuring

109

Brass ring in packing

lantern ring

110

impeller wear

blade tips

111

types of seals used in pumps

dynamic and static

112

when pumping clear uncontaminated h2o water

used solid packing

113

unbalanced pump

off center in a concentric housing

114

best chain to use in abrasive conditions?

mill chain

115

blow by

oil leaking into the crankcase

116

in an emergency

lap mechanical seal

117

overspeed trip on turbine

110% to 115%

118

measure stroke

distance from BCC- TDC

119

how do you measure growth

with laser, optical, etc

120

axial growth in a turbine is controlled with

a key

121

tenon

shrouds - tip of the blade?

122

full load to no load

speed droop

123

To change the operating speed (rpm) on the governor

Adjust the spring

124

troubleshooting question

systematic approach
ask good question
do one thing at a time

125

maintenance on a valve stem

tighten nut

126

how is shroud attached?

it's riveted in sections over a tenon

127

what is the critical speed of a rotor?

Is determined by it's natural frequency. At this speed the motor will shake violently. The machine must accelerate quickly through the critical speed to avoid this