1
Q
What 3 things do bearings do?
A
- reduce wear
- absorb/dissipate heat
- guide/aid moving parts
Pumps Bearings Turbines - pg. 5
2
Q
What are the three kinds of loads?
A
- Radial
- Thrust/axial
- Combination
Pumps Bearings Turbines - pg. 6
3
Q
The _______ helps keep the steel balls of a bearing in position, aligned correctly, and separated at a fixed distance from eachother.
A
cage
Pumps Bearings Turbines - pg. 8
4
Q
The formula ‘dN’ defines the ________ _______ of bearings.
A
speed limitation
Pumps Bearings Turbines - pg. 12
5
Q
What does ‘dN’ equate to? (what do the variables represent)
A
shaft diameter (millimeters) multiplied by RPM.
Pumps Bearings Turbines - pg. 12
6
Q
What two things do bearing housings do?
A
- Protect bearing from environmental corrosion
- Provide accurate shaft alignment and support for radial/thrust loads
Pumps Bearings Turbines - pg. 14
7
Q
What can help in extending bearing life?
A
Proper maintenance and lubrication
Pumps Bearings Turbines - pg. 16
8
Q
To get the most out of bearings what 5 factors must be considered?
A
- Manufacturers guidelines
- Type of lubricant
- Application (load and speed)
- Maintain dust/moisture free environment
- Other parts that need replacing
Pumps Bearings Turbines - pg. 17
9
Q
Do new bearings taken from sealed packaging need to be cleaned?
A
No, but they may be cleaned, dried and lubricated prior to installation.
Pumps Bearings Turbines - pg. 32
10
Q
_______ fitting or ________ fitting is usually sufficient to ensure no movement between the shaft and bearing.
A
Press; shrink
Pumps Bearings Turbines - pg. 34
11
Q
What are the two methods to heating a bearing to help fit a shaft?
A
- Induction heater
- Electric oven
Pumps Bearings Turbines - pg. 35
12
Q
Heating a bearing above _______ may affect its hardness.
A
250 degrees Fahrenheit
Pumps Bearings Turbines - pg. 36
13
Q
What’s the best way lubricant functions to smooth operation of a machine?
A
It provides a heat-transfer medium
Pumps Bearings Turbines - pg. 44
14
Q
Thrust bearings support _______ _______ .
A
axial loads
Pumps Bearings Turbines - pg. K-7
15
Q
The __________ is a high-tin (soft) material metallurgically bonded to the body of the thrust shoe.
A
babbitt
Pumps Bearings Turbines - pg. K-8
16
Q
What 2 functions does the babbitt have?
A
- Traps/imbeds contaminants
- Protects shaft from damage when oil film is interrupted
Pumps Bearings Turbines - pg. K-8
17
Q
The whole assembly of a thrust bearing runs ___________________ .
A
submerged in in a bath of oil.
Pumps Bearings Turbines - pg. 53
18
Q
What are the four main indicators for determining bearing condition?
A
- Temperature
- Noise/Vibration
- Condition of seals
- Proper lubrication
Pumps Bearings Turbines - pg. 66
19
Q
What are the 3 most common root causes for premature bearing failure?
A
- Incorrect lubrication
- Contamination
- Improper Installation/Misalignment
Pumps Bearings Turbines - pg. 69
20
Q
What is the main root cause for premature bearing failure?
A
Improper installation or misalignment
Pumps Bearings Turbines - pg. 69
21
Q
What is the most common type of wear in bearings?
A
spalling
Pumps Bearings Turbines - pg. 72
22
Q
Spalling occurs when?
A
When the metal of any bearing becomes fatigued and pieces of metal flake off the rolling elements and races.
Pumps Bearings Turbines - pg. 72
23
Q
The soft metal of plain bearings often has low melting temp. Because of this, partial ________ or _______ usually leaves the bearing metal streaked or smeared in appearance.
A
softening or melting
Pumps Bearings Turbines - pg. 76
24
Q
Why are bearings important in a machine?
A
Bearings reduce the amount of friction between moving parts.
Pumps Bearings Turbines - pg. 87
25
An external mechanical resistance against which a machine must act is also known as _______ .
Load
Pumps Bearings Turbines - pg. 87
26
The two main types of bearings are _______ and _______ .
Plain and rolling-element
Pumps Bearings Turbines - pg. 88
27
Which type of bearing is best suited for heavy-duty applications and long spans?
Tapered roller bearings
Pumps Bearings Turbines - pg. 88
28
Roller bearings use seats and shields to ________________ .
Keep moisture and contaminants out.
Pumps Bearings Turbines - pg. 89
29
What are the two basic types of bearing housings?
Pillow block and flanged housings
Pumps Bearings Turbines - pg. 89
30
What is the prime consideration when replacing a bearing?
The current bearing type
Pumps Bearings Turbines - pg. 89
31
In ________ pumps, flow from the pump is blocked or resisted, causing system pressure to increase. This pressure works against the pump and reduces delivery rate.
centrifugal (non-positive displacement)
Pumps Bearings Turbines - pg. 111
32
In a ______ ______ pump, a slight vacuum pressure causes fluid to be forced into the pumps inlet.
rotary vane (positive displacement)
Pumps Bearings Turbines - pg. 114
33
In a rotary vane pump, slots in the port plate are specially shaped so that fluid enters pumping chambers as they ______ size and is forced out as they ______ size.
increase; decrease
Pumps Bearings Turbines - pg. 114
34
In the _____ _____ pump, another type of gear pump, chambers are formed in spaces between gear teeth and the pump housing.
external gear
Pumps Bearings Turbines - pg. 116
35
Delivery rate of a pump depends on two characteristics:
1. ___________ , which is the amount of fluid delivered each time the drive shaft rotates.
2. ___________ , the number of times the drive shaft rotates each minute.
1. Displacement
2. Drive Speed
Pumps Bearings Turbines - pg. 126
36
What must be done to change the delivery rate of a pump?
Vary either the pump's displacement or the speed of the drive shaft rotation.
Pumps Bearings Turbines - pg. 126
37
If the cam ring in a variable displacement vane pump is moved to an under-the-center position, fluid will flow ______________.
in a reverse direction
Pumps Bearings Turbines - pg. 128
38
In regards to flow, what does the cam ring positioning do in variable displacement vane pumps?
increase, decrease, cease, or reverse flow
Pumps Bearings Turbines - pg. 128
39
_________ pumps can pump to a shut valve or system without the threat of damaging the system. (Eventual damage may occur)
Centrifugal
Pumps Bearings Turbines - pg. 149
40
The ________ is the beginning of the volute and is the closest surface to the outside diameter of the impeller.
cutwater
Pumps Bearings Turbines - pg. 153
41
The ________ is the beginning of the discharge nozzle.
cutwater
Pumps Bearings Turbines - pg. 153
42
What are the 6 classifications of centrifugal pumps?
1. single-stage
2. multi-stage
3. suction position
4. impeller
5. volute
6. shaft position
Pumps Bearings Turbines - pg. 154
43
When the impeller shaft is connected to the prime mover with a coupling device, it is said to be _____________ or _________ .
direct-coupled or frame-mounted
Pumps Bearings Turbines - pg. 158
44
What are the 4 common classifications of impellers?
1. Radial Vane
2. Frances Vane
3. Propeller / Axial Flow
4. Mixed flow
Pumps Bearings Turbines - pg. 159
45
__________ are used to provide an economically replaceable wear surface and renewable clearance between the impeller and casing.
wear rings
Pumps Bearings Turbines - pg. 164
46
A wear ring provides a replaceable surface for maintaining close _____ necessary in centrifugal pumps.
tolerances
Pumps Bearings Turbines - pg. 164
47
The replaceable ring attached to the hub of the impeller near the suction opening is known as the _______ .
impeller wear ring
Pumps Bearings Turbines - pg. 164
48
The ring attached to the impeller casing is known as the ________ .
casing wear ring
Pumps Bearings Turbines - pg. 164
49
Selection of the proper wear ring is based on what 3 factors?
1. liquid being handled
2. pressure differential across the joint
3. rotation speed
Pumps Bearings Turbines - pg. 164
50
What are 3 common types of wear rings?
1. flat type
2. L-Shaped
3. labyrinth
Pumps Bearings Turbines - pg. 164
51
_____ rings maintain impeller clearance on either the outside diameter or axially.
Flat
Pumps Bearings Turbines - pg. 165
52
________ rings seal on both the outside diameter and axially.
L-Shaped
Pumps Bearings Turbines - pg. 165
53
What will happen to the packing if a continuous flow of cooling and lubricating liquid is not maintained through the stuffing box?
It can overheat
Pumps Bearings Turbines - pg. 168
54
A spacer or _______ is placed between the rings of packing in the stuffing box when an external source of cooling is used.
lantern ring
Pumps Bearings Turbines - pg. 169
55
Guide ________ provide critical support to the impeller and shaft assembly and maintain the position of the impeller both radially and axially.
bearings
Pumps Bearings Turbines - pg. 170
56
A _______ is a spiral casing for a pump designed so that the speed of the liquid is converted into pressure without shock.
volute
Pumps Bearings Turbines - pg. 179
57
What is opened to remove trapped air removed from a pump?
suction valve and casing valve
Pumps Bearings Turbines - pg. 193
58
If a pump has been operating well and suddenly looses suction, what is a likely cause other than blockage?
Air may be entering the system through the suction line or packing gland.
Pumps Bearings Turbines - pg. 198
59
What are 8 common mechanical reasons excessive vibration may be caused in a pump?
1. misalignment of the unit
2. distorted foundation/baseplate
3. worn impeller wear rings
4. worn bearings
5. bent shaft
6. improperly balanced impeller
7. clogged impeller
8. broken impeller
Pumps Bearings Turbines - pg. 198
60
_______ is the formation of vapor bubbles due to a sudden pressure reduction and a sudden collapse of the bubbles as pressure increases.
Cavitation
Pumps Bearings Turbines - pg. 200
61
Cavitation limits flow and is extremely destructive to the __________ . The bearings may be damaged along with the impeller and wear rings.
rotating elements.
Pumps Bearings Turbines - pg. 200
62
What are the steps/procedure for securing a centrifugal pump?
1. Close discharge
2. Stop the motor
3. Close suction valve
Pumps Bearings Turbines - pg. 202
63
With accurate ______ data taken at regular intervals, the operator can see changes in shaft alignment, bearing condition, and other aspects of the unit's operation.
vibration
Pumps Bearings Turbines - pg. 211
64
__________ rotate on an axis to push/pull fluid.
Centrifugal pumps
Pumps Bearings Turbines - Supplemental
65
_________ pumps use linear motion.
Reciprocal
Pumps Bearings Turbines - Supplemental
66
What are the 2 categories of pumps?
Positive displacement and Non-Positive displacement
Pumps Bearings Turbines - Supplemental
67
What type of bearings are used on the large pumping units used at DWR?
Plain bearings
Pumps Bearings Turbines - Supplemental
68
What are two classes of positive displacement pumps?
1. Reciprocating
2. Rotary
Pumps Bearings Turbines - Supplemental
69
Turbine generators use _______ bearings.
Plain
Pumps Bearings Turbines - Supplemental
70
What does the bearing housing do?
It offers protection and alignment.
Pumps Bearings Turbines - Supplemental
71
What 3 factors determine how well a centrifugal pump works?
1. Density of fluid
2. Speed of rotation (RPM)
3. Diameter of impeller
Pumps Bearings Turbines - Supplemental
72
What is the short description for Bernoulli's Principle?
Velocity is inversely proportional to pressure
Pumps Bearings Turbines - Supplemental
73
________ supplies water to wear rings before a unit starts.
seal water
Pumps Bearings Turbines - Supplemental
74
How does a flowmeter prevent false positives?
use of check valves
Pumps Bearings Turbines - Supplemental
75
___________ are mechanical devices developed for the purpose of converting water power potential into usable mechanical energy.
Hydraulic turbines
Pumps Bearings Turbines - pg. 231
76
________, a type of impulse wheel, is used for heads of 800 ft. or more.
Pelton-type runner
Pumps Bearings Turbines - pg. 231
77
What are the two classifications of hydraulic turbines? (not pumps)
Reaction and Impulse
Pumps Bearings Turbines - pg. 231
78
What hydraulic turbines have the greatest capacity?
Francis units
Pumps Bearings Turbines - pg. 234
79
What are the largest type of hydraulic turbine?
Propeller
Pumps Bearings Turbines - pg. 234
80
________ type turbines may be designed for large capacity but are limited as to head.
Propeller
Pumps Bearings Turbines - pg. 234
81
Most ________ turbines are comparatively small.
impulse
Pumps Bearings Turbines - pg. 234
82
In impulse turbines, the size of the jet and the amount of water discharged is usually controlled by _______ .
needle valves
Pumps Bearings Turbines - pg. 235
83
Some older models of impulse turbines use a __________ instead of a deflector vane to protect against runaway speeds on load rejection.
tilting nozzle
Pumps Bearings Turbines - pg. 236
84
The ___________ (also known as the spiral case) of a reaction turbine forms a water passage completely around the turbine and allows water to enter uniformly from all sides.
scroll case
Pumps Bearings Turbines - pg. 238
85
The spiral or scroll case of a turbine is always arranged so that the direction of the flow of water around the spiral is in the same direction as the rotation of the turbine ________ .
runner
Pumps Bearings Turbines - pg. 238
86
The portion of the water passage of a reaction turbine which conducts the water discharged from the turbine runner to the tailrace is the _______________ .
draft tube
Pumps Bearings Turbines - pg. 238
87
When pumping, the draft tube is known as the ___________ .
suction elbow
Pumps Bearings Turbines - Supplemental
88
The ______ ring is a manner as to accelerate uniformly the velocity of the water entering the turbine.
speed
Pumps Bearings Turbines - pg. 239
89
To relieve excessive negative pressures, which occur under the cover plate of a turbine when wicket gates are closed rapidly, one of the usual accessories installed is a __________ or __________ to admit air to the runner chamber. This is known as _________ .
vacuum breaker; relief valve; turbine venting
Pumps Bearings Turbines - pg. 241
90
The action of hydraulic pressure is used to operate mechanical equipment by means of _______ or hydraulic power cylinders.
servomotors
Pumps Bearings Turbines - pg. 241
91
As applied to turbine gates, servomotors consist of a securely anchored high pressure cylinder and piston, controlled by _______ operated duplex valves.
governor
Pumps Bearings Turbines - pg. 241
92
The ________ turbine develops its power almost entirely by the action of the weight of the water.
propeller
Pumps Bearings Turbines - pg. 244
93
The ________ turbine (propeller type) shaft is hollow and a hydraulic servomotor is mounted between the turbine and the generator shaft.
Kaplan
Pumps Bearings Turbines - pg. 245
94
The Francis turbine has how many seal rings (or wear rings)?
4
Pumps Bearings Turbines - pg. 249
95
Pelton ___________ are moved by servomotors which are controlled by governing systems.
needle valves
Pumps Bearings Turbines - Supplemental
96
With Francis type turbines, the wicket gate is moved by means of ____________ .
servomotors
Pumps Bearings Turbines - Supplemental
97
Servomotors move the pitch of turbine blades (kaplan) and gates to do what 3 things?
control flow, increase efficiency, and shut off flow in case of emergency.
Pumps Bearings Turbines - Supplemental
98
The _______ type turbine is the most versatile and widely used.
Francis
Pumps Bearings Turbines - Supplemental
99
What type turbine can be used to generating and pumping?
Francis
Pumps Bearings Turbines - Supplemental
100
The _________ provides circular flow and drags a film of oil with it.
thrust runner
Pumps Bearings Turbines - Supplemental
101
Load supported by high pressure fluid is considered _________ .
hydrostatic
Pumps Bearings Turbines - pg. K-3
102
Load supported by balls or rollers is a __________ .
rolling contact
Pumps Bearings Turbines - pg. K-3
103
Load supported by a lubricant film is considered ________ .
hydrodynamic
Pumps Bearings Turbines - pg. K-3
104
A ________ is the part of a rotating shaft, axle, roll, or spindle that turns a bearing.
journal
Pumps Bearings Turbines - pg. 24
105
Damage caused by rubbing, chafing or wearing away is known as ___________ .
fretting
Pumps Bearings Turbines - pg. 217
106
The term ______ means in the direction extending from the center point of a shaft.
radial
Pumps Bearings Turbines - pg. 50
107
_______ is indentations formed in the surface of a bearing.
Pitting
Pumps Bearings Turbines - pg. 217
108
A ______ allows cooling fluid into the stuffing box.
lantern ring
Pumps Bearings Turbines - pg. 169
109
The term ______ means in the direction of or along the axis.
axial
Pumps Bearings Turbines - pg. 49
110
________ is the comparison of the speeds of all types of turbines for a given head and capacity.
Specific speed
Pumps Bearings Turbines - pg. 253
111
The vertical ribs that separate and support the speed ring are ___________ .
stay vanes
Pumps Bearings Turbines - pg. 239
112
________ is the amount of space between the component parts of a bearing assembly.
Clearance
Pumps Bearings Turbines - pg. 23
113
Where are wear seals located?
Pump casing (casing ring) and impeller (rotating ring)
Pumps Bearings Turbines - Review
114
A bearing cage provides precise _____ and _____ .
position and alignment
Pumps Bearings Turbines - Review
115
What method of bearing installation involves slow movement between the shaft and bearing?
press fitting
Pumps Bearings Turbines - Review
116
Overheating a bearing will make it lose its _____ and _____ it.
temper; soften
Pumps Bearings Turbines - Review
117
Does loss of prime in a pump casing cause vibration?
No
Pumps Bearings Turbines - Review
118
What does a servomotor do on Kaplan turbines?
adjust wicket gates
Pumps Bearings Turbines - Review
119
On an umbrella turbine unit, the thrust runner sits ______ the rotor.
below
Pumps Bearings Turbines - Review
120
What are the 3 methods for stopping impulse turbines?
deflector plates, brake nozzles, tilting nozzle
Pumps Bearings Turbines - Review
121
After water is used for generation, it goes to the _____ and then to the ______ .
draft tube; tail race
Pumps Bearings Turbines - Review
122
In regards to water head, what determines the type of turbine used?
operate head
Pumps Bearings Turbines - Review
123
What controls the size of the jet?
needle
Pumps Bearings Turbines - Review
124
Improper installation of a bearing can cause _____ _____ .
premature failure
Pumps Bearings Turbines - Review
125
To determine proper lubrication schedule we must consider _______ and ______ .
equipment application and speed of unit
Pumps Bearings Turbines - Review
126
What type of pneumatic motor was used in construction of Coulee Damn?
steam powered sledge hammer
Pumps Bearings Turbines - Review
127
On GE thrust bearings, the greatest pressure area will be __________ .
in the middle
Pumps Bearings Turbines - Review
128
What is the advantage of Kingsbury pivot shoe bearing over a pillow block thrust bearing?
It is submerged in oil
Pumps Bearings Turbines - Review
129
Single stage turbines use _____ wear rings.
flat
Pumps Bearings Turbines - Review
130
In which classification of hydraulic pump do chambers increase in size to draw fluid in and decrease to eject? What are three types?
positive displacement; rotary, piston, axis
Pumps Bearings Turbines - Review
131
Vibration is a symptom of bad ______ or ______ impeller.
alignment; damaged
Pumps Bearings Turbines - Review
132
When installing packing, odd number of layers should have seams staggered at ______ where even numbers should have seams staggered at _____ .
120 degrees; 90 degrees
Pumps Bearings Turbines - Review
133
A Kaplan impeller can be either ____ or _____ .
fixed or automatic
Pumps Bearings Turbines - Review
134
In a kaplan impeller, the shaft is _____ .
hollow
Pumps Bearings Turbines - Review
135
On an impeller turbine, what safety measure prevents sudden shock when the system is arrested?
vacuum breaker
Pumps Bearings Turbines - Review
136
What are two ways to check clearance without disassembling a unit?
feeler gauges and swing check
Pumps Bearings Turbines - Review
137
What increases the velocity entering the turbine?
scroll case
Pumps Bearings Turbines - Review
138
Is it possible to have a Kingsburry thrust bearing, with pivoting shoes, to not have an external pressure source?
Yes
Pumps Bearings Turbines - Review
SJFDCLS
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