8th Six Months Flashcards
(351 cards)
1
Q
You can control chain tension by changing shaft centers or using a?
A
Idler sprocket
2
Q
A roller chain should be allowed to sag ___ percent of the distance between sprocket centers.
A
About 2
3
Q
- In chain operations, the areas of greatest load are the?
A
Chain joints
4
Q
You should make your first full-scale inspection of a new drive chain after ____ hours of operation?
A
24
5
Q
Chain side plates that show signs of uneven wear usually indicate that the?
A
Drive is misaligned
6
Q
In a vertical chain drive without an idler the shafts should be installed at an angle of no more than?
A
60°
7
Q
The most common cause of drive chain failure is?
A
Improper lubrication
8
Q
Which of the following describes the type III lubrication method?
A
Splash
9
Q
- A scraping or slapping noise during a test run of a chain drive may indicate that?
A
The chain is striking something
10
Q
Before using chain that has been stored on open reels you should?
A
Clean it with solvent
11
Q
After mounting sheaves and pulleys, you should check their alignment with a?
A
Straight edge
12
Q
The best way to tighten a V-belt that has stretched is to?
A
Adjustable center distance between sheaves
13
Q
A splice commonly used on low-speed flat belts is the ___ splice?
A
Stepped
14
Q
. If a new flat belt is running well, how long should you test run it under normal load?
A
48 hours
15
Q
- A burned spot on a belt probably indicates?
A
Belt is overloaded
16
Q
Which type of belt is installed on sheaves rather than on pulleys?
A
V belt
17
Q
If a v-belt in a multi belt drive shows wear you should?
A
Replace the full set of belts
18
Q
Which of the following is the correct way to check a V-belts tension?
A
Apply a specific amount of force to the top side of the belt
19
Q
Which of the following is the best way to take up slack in a flat belt?
A
Adjust the center distance
20
Q
The pulleys for a positive drive belt have a?
A
Flange on each side
21
Q
Which of the following drives permits practically no misalignment of the shafts?
A
Gear
22
Q
The critical dimension that ensures accurate meshing of a worm and worm gear is its?
A
Distance between the centers
23
Q
When mounting spur or helical gears that have only one hub, you should position the hub?
A
Away from the bearing
24
Q
When cracked or broken areas appear on teeth that are almost new, the cause is probably a?
A
Foreign object
25
If the metal at the tips and roots of gear teeth has been gouged or worn, the cause is probably?
Too tight a fit between gears
26
Which of the following happens to open gearing during the run in period?
Gear polish up
27
The DP of a gear is the ratio of the number of teeth to the ____ in inches.
Pitch diameter
28
Which of the following is used to check gear alignment after installation?
Steel square
29
What should you do if spalling occurs in an open gear drive?
Gear treat the teeth
30
Which of the following is the best solution for gearing with cracked rims?
Replace the gear
31
When installing an enclosed gear drive on the floor you should mount the feet on the?
Steel base pads
32
What components of an enclosed gear drive prevents the buildup of pressure or the formation of a vacuum inside the drive housing?
Breather
33
If an enclosed gear drive is to be stored in the plant for a long time, you should?
Fill the drive completely with oil
34
Most unusual noises that develop after an enclosed gear drive has run a while originate in the?
Shaft bearings
35
What does discoloration of worm gear teeth indicate?
Burning by overloading
36
Which tool is used to check the levelness of an enclosed gear drive on its foundation?
Spirit level
37
Which is the most common method of lubrication for bearings on enclosed gear drives?
Splash
38
During the run in period you should run the drive system at half load for __ to ___hours.
8-10
39
After a gear drives first week of operation under full load you should?
Check the oil level
40
Which of the following is found on the nameplate of an enclosed gear drive?
Load capacity
41
Which elements of the drive package should you move to set the coupling gap?
Motor
42
What instrument is used when very precise coupling alignments must be made?
Dial indicator
43
What instrument is used when very precise coupling alignments must be made?
Dial indicator
44
A floating shaft coupling should be used when the?
Drives exert axial thrust
45
If the power requirements of a driven machine have been changed so that over-loading occurs you can solve the problem by installing the?
Next larger coupling
46
A coupling can serve all of the following purposes except?
Insulate against high temperatures
47
The gap between spacer couplings and the hubs should be ___ inches?
0
48
What is the usual cause of whipping on a floating shaft?
Excessive misalignment
49
An uneven wear pattern on a gear type coupling is usually a sign of?
Misalignment
50
The slack in the fit between coupling components is known as?
Backlash
51
The most common cause of failure in jaw clutches is?
Jaw breakage
52
V-belt sheaves, shafts and gears can all be used as?
Takeoff members
53
Localized wear on clutch friction surfaces often indicates?
Misalignment
54
Frequent slippage of a brake or clutch is usually an indication of?
Overloading
55
Chatter is usually caused by?
Loose or faulty actuating devices
56
Friction clutches use one or more discs to?
Transmit torque to the load
57
Rapid wear between the friction surfaces by an electric brake or clutch is usually the result of?
Overheating
58
When the slip speed of a clutch drops to zero, the maximum torque of the clutch can exert?
Increases
59
The capacity of a clutch to dissipate heat depends on its size and?
Armature speed
60
If a brake or clutch fails to engage properly, the first thing to check is the?
Voltage supply to the coil
61
At _____ output speed, the flanges on the input shaft of an adjustable-speed drive are?
Maximum; closest together
62
The best protection against unwanted heat in a an enclosed drive is a?
Steel baffle
63
When test running and adjustable speed drive under no-load conditions, it is necessary to operated the drive?
Through its full speed range
64
If you find ridges in a drives sheave flanges on an adjustable speed drive you should?
Sand or polish the ridges away
65
In an enclosed drive, high temperatures usually result from a?
Overloading the shaft bearing
66
The amount of slip between a turbine and its impeller is normally a difference of ____ to ____ percent at full load.
3 to 5
67
A condition called a "stall load" can occur in a fluid coupling when the impeller _____ and the turbine ______?
Rotates; does not rotate
68
Over heating in a fluid coupling is usually caused by ?
Too much slip
69
A polyphase torque converter has _____ stators that _____?
Two or more; rotate
70
If you find seals that are hard and cracked when you are inspecting a coupling, you should ?
Replace them
71
An enclosed gear drive thermal capacity is usually expressed in?
Horsepower
72
When you need to change the speed of a load shaft you should select a drive with a?
Adjustable speed belt
73
The major cause of drive failure is?
Improper lubrication
74
If an overload occurs in a drive system that is equipped with a spring-operated overload device the?
Sprocket will slip
75
When test running a drive prior to placing it in service, you should run the drive under no-load conditions for?
20-30 minutes
76
Which of the following diagrams represents the proper sequence for tightening hold-down bolts when installing an enclosed adjustable speed drive?
C
1 3
2 4
77
The best way to determine the correct running clearance in a plain-bearing is to?
Consult manufacturers charts and tables
78
The ability of bearing material to dissipate excessive heat generated during operation is called?
Thermal conductivity
79
The ability of bearing material to flow slightly when loaded is called?
Conformability
80
An advantage of grease compared to oil in lubricating a plain bearing is that?
Newly applied grease forced old lubricants out
81
Discoloration in plain bearings is generally a symptom of?
Excessive heat
82
Which of the following should be used to measure the running clearance of a plain bearing?
Feeler gauge
83
Which method should be used to remove moisture from a bearing shell after it has been cleaned?
Preheating
84
When building a plain bearing liner, coat the mandrel with ___ to keep molten Babbitt from clinging.
White lead
85
What is the purpose of the grooves cut onto a plain bearing liner?
Circulate lubricant
86
Which is the most likely cause of screeching from a plain bearing during operation?
Clearances are too tight
87
If you must leave your workplace temporarily, what care should you give a new, unmounted antifriction bearing?
Wrap it in oil resistant paper
88
. To prevent creeping of an inner bearing ring around the shaft, you should mount the inner ring with an ___ fit.
Interference
89
You can force an antifriction bearing into position on the shaft by using an arbor press or by impact, if the bearing has an O.D. of?
4 inches or less
90
A bearing is driven up a split tapered adapter by?
Tightening a heavy duty locknut
91
At approximately what temperature should you begin to suspect a bearing problem?
At approximately 185°F
92
You clean an antifriction bearing before installation if it?
It will be lubricated by automatic oil mist
93
If the shoulder is too low when seating an antifriction bearing on the shaft the?
Inner ring may distort
94
When inspecting a tapered shaft by blueing the gauge bore, a ___ % blueing transfer is acceptable?
80%
95
When cold mounting an antifriction bearing, you must?
Lubricate the bearing bore and shaft with light oil
96
Which of the following is not an approved way to heat a roller bearing for a temperature mount?
Gas operated torch
97
What is the correct tool to use when removing a locknut from an antifriction bearing installation?
Spanner wrench
98
When you use a puller to remove a taper-mounted bearing, what should you do with the locknut?
Back the nut off several turns
99
An aluminum heating ring is designed for mounting and dismounting the inner rings of a ___ bearing.
Cylindrical roller
100
When you use an aluminum heating ring to expand a bearing, heat the ring to?
500°F
101
If you have cleaned and inspected an antifriction bearing but do not intend to reuse it immediately, how should you treat it before wrapping it in oil-resistant paper and storing it?
Fill it with grease
102
The two main methods of removing antifriction bearings are?
Impact and heating
103
Which of the following is a correct way to remove an antifriction bearing with a diameter smaller than 4 inch?
Arbor press
104
The two important dimensions of a bearing puller are spread and?
Reach
105
To remove a bearing, a splitter may be used with a?
Mechanical puller
106
Which of the following should not be used to clean an antifriction bearing when inspecting it?
Steam
107
Which type of bearing seal keeps out water, dirt, and contaminants most effectively?
Contact seal
108
Which type of antifriction bearing can tolerate the most internal misalignment?
Spherical roller bearing
109
The correct tolerance range for shafts from 2 to 4 inches in diameter is nominal to?
-.001 inches
110
When you lubricate bearings with grease, the actual lubricant is ___, which is held in suspension.
Mineral oil
111
As a rule, the interval between lubrication renewals is cut in half for every 27 degrees Fahrenheit increase in temperature above?
160°F
112
. A special type of pillow block sometimes used on belt conveyors is called a?
Takeup
113
When using the grub screw method to hold a bearing in a pillow block, use?
No collar
114
To find the takeout amount needed to calculate final clearance when installing a bearing, refer to the?
Manufacturers chart
115
Which type of lubricant increases the effectiveness of a labyrinth seal?
Grease
116
Bearing temperature is typically ___ to ___ degrees Fahrenheit higher than the temperature of the housing.
15° to 25°
117
The threads of an acme screw are?
Squared off & thick
118
Ball bearing screws are designed to?
Move loads vertically and horizontally
119
The screw in a ball bearing screw is supported by?
Standard ball bearings
120
. In a contact seal, what forms the actual seal?
A thin film of oil
121
Before you install a lip seal, chamfer the end of the shaft and the leading edge of the housing bore at an angle of ___ to ___ degrees.
15 to 30
122
The rolling contact of a ball bearing screw is ___ % efficient.
90%
123
Which of the following carries the load moved by a ball bearing screw?
Ways
124
When preparing a ball bearing screw for installation, use a ___ to expand the inner ring of the bearings.
Hot oil bath
125
Which seal is most effective when large quantities of contaminants are present close to the machinery?
V-ring
126
Which seal material works well for machines operating at extremely low temperatures?
Silicone
127
1 The two units of measuring liquid pressure are?
P.S.I ; Foot of head
128
The available NPSH of a system should be _____ the required NPSH of the pump.
Equal to or greater than
129
The formation of vapor pocket or bubbles within a liquid id called?
Cavitation
130
The horsepower required to actually drive a fluid-handling pump is called the?
Brake hp
131
One electrical horsepower equal ____ watts.
746
132
The area that surrounds and houses the packing in a pump is called the?
Stuffing box
133
When installing four or more packing rings, you should stagger the joints ____ degrees apart?
90
134
The most common mechanical seal configuration is the ____seal?
Single internal
135
9 In some mechanical seals, the rotating element is secured to the shaft by a?
Boot
136
The major cause of burned seals is?
Improper lubrication
137
After grouting a baseplate, you should allow the grouting mixture to set for at least?
48 hours
138
When removing springs from pump feet, you should measure movement with a?
Dial indicator
139
Unwanted movement of a pump shaft along its axis is called?
End play
140
Cavitation is caused by
Pressure loss
141
Loss of clearance between wearing rings is called?
Ring seizure
142
On a pump that has both bearings on the same side of the impeller, the bearing nearest the impeller is called the ______ bearing?
Inboard
143
The most common sign of cavitation in a pump impeller is?
Putting on the back side of the vanes
144
In general, runout on a pump shaft should not exceed ____ inches.
.003
145
Too much clearance between the stationary rings and the impeller or rotating rings of a centrifugal pump will cause?
Fluid leakage
146
When installing a new gasket, you may wish to apply ____ to the lower half of the casing.
Shellac
147
The most commonly used type of all rotary pumps is the ______ pump.
External gear
148
In a vane-type rotary pump, what keeps the sliding vanes in contact with the pump housing?
Centrifugal force
149
The riser used to vent a system at the discharge side of the pump should be about _______ times as long as the diameter of the pipe?
5
150
Internal bearings on rotary pumps are most often lubricated by?
The fluid being pumped
151
If a rotary pump is not delivering fluid at its discharge side, the first thing you should do is?
Stop the pump
152
1. Which method is used to measure a pipe with a fitting at one end?
End to center
153
Which of the following displayed symbols describes a flanged tee?
|
=
---||----|-----||--
154
Which type of flange is used to seal the end of a pipe?
Blind
155
Given a 45 degree offset shown with a 41 inch travel a center to face elbow dimension of 2 inch and a ¾ inch length, what is the end to end pipe length?
38.5 inches
156
Straight internal pipe threads in pipe couplings are represented by the code letters?
Npsc
157
. In complete pipe specifications, code letters are preceded by two numbers which indicate the?
Nominal pipe size and number of threads per inch
158
The distance from a given point on one pipe thread to the same point on the next thread, measured parallel to the pipe centerline, is called the?
Pitch
159
You need to replace a threaded pipe between 45 degree elbows in a straight offset. The set is 5 ft, and the travel is 7.07 ft. The center-to-face dimension of each 45 elbow is 2 in., and the pipes thread length is 3/4 in. The total end-to-end length of the replacement pipe is?
82.34 inches
160
Ratchet threaders can be used on pipe up to about ____ inch in diameter.
6
161
Socket-welding fittings are used for joining pipe of what diameters?
4 inches or less
162
Backing rings should always be made of?
Material compatible with the pipe material
163
Squareness is a term indicating that a pipe forms a _____ angle with another.
90 degree
164
The major assembly consideration when fabricating flanged connections for a rolling offset is?
Aligning the holes
165
The usual gap between pieces of pipe to be butt welded is approximately?
3/16 inch
166
A major advantage of thermoplastic pipe is that?
It is highly resistant to corrosion
167
Which of the following is a fiberglass-reinforced thermosetting pipe material?
RTRP
168
The solvent cement used to install fittings on thermoplastic pipe requires _____ hours to cure completely
1/2 to 4 hours
169
When installing threaded fittings on plastic pipe, you should tighten the joint by hand or with a?
Strap wrench
170
To ensure a good bond when installing bell fittings on thermosetting pipe, the ends of the pipes should be?
Lightly sanded
171
What kind of hanger is used if a rigid hanger would swing more than 4 degrees?
Roller
172
A steam trap is a pipefitting accessory that removes?
Condensate
173
Steam traps should he installed at the ______ point in the system.
Lowest
174
Which of the following fixtures is used to remove very small particles from a piping system?
Filter
175
What kind of expansion joints can be used where temperature changes cause axial pipe movements?
Slip and bellow joints
176
Water is usually carried in ______ tubing; If it is under high pressure, _____ tubing is usually used.
Copper; stainless steel
177
A flareless compression fitting is one that?
Bites into tubing
178
Annealing is sometimes necessary to make tubing?
Easier to bend
179
When you use a cutter to cut tubing, the cutter should _____ and the tubing should ___?
Rotate; not rotate
180
To get the most accurate measurement of required tubing length, you must measure along the path of the tubes?
Centerline
181
The tensile strength of tubing is based on the ______ and the ______?
Tubing material; wall thickness
182
How does increasing the operating temperature affect the strength of tubing?
Decreases it
183
What type of fitting is commonly used on tubing that carries a flammable liquid or gas?
Flared
184
What is the first step in installing a flared fitting?
Slide the nut over the tube
185
What is the most common cause of leaks in a tubing system?
Poor fitting connection
186
What is the most frequently used hydraulic fluid?
Oil
187
What device is commonly used to keep hydraulic systems from building up excess pressure?
Relief valve
188
What type of fittings should be used with copper tubing in hydraulic systems?
Brass
189
If the pump in a hydraulic system is noisy, the most likely cause is a?
Insufficient fluid supply
190
Contaminated fluid in a hydraulic system often causes?
Fluctuating pressure
191
A typical multipurpose industrial hose can carry saturated steam at pressures of up to?
150psi
192
A shaft that serves to support a fitting during assembly is called a?
Mandrel
193
The most common method of attaching reusable fittings to hose is?
Threading
194
Calculate the required hose length if a 40 degree bend is to be made in a hose and the radius of the bend is 8 in.
5.58 inches
195
Hydrostatic tests of a hose system should be conducted at ___ percent of the recommended working pressure of the hose?
150
196
The most important dimension of a gasket from a total performance standpoint, is its?
Thickness
197
The electrical signal generated by a profilometer is converted into a reading displayed in?
RMS
198
Waviness in flange surfaces is usually expressed in _____ of an inch.
Thousandths
199
Waviness in flange surfaces is usually expressed in _____ of an inch.
Thousandths
200
Coatings serve to reinforce a joint seal and keep the gasket from?
Creeping
201
TFE-based gasket strips can accommodate operating temperatures of up to?
250°F
202
Which of the following valve materials is the best choice for service conditions that include high pressures, high temperatures, and corrosive fluid?
Stainless steel
203
. If a valve must be removed frequently for service or repair, the valve-to-pipe connection should be?
Threaded
204
The first step in stopping leakage around the stuffing box of a gate valve is to?
Tighten the gland bolt nuts
205
If the stem of a globe valve does not move freely, one likely cause is a?
Damage spot on the thread
206
What is usually the first indication of a valve problem?
Leakage
207
The first part of a diaphragm valve to wear out it usually?
The diaphragm
208
What causes a pop safety valve to open?
Pressure rising above a preset value
209
For most pop safety valve, pressure and temperature are usually limited to?
250-450psi
210
Chatter in pop safety valves is caused by a _____ volume of flow at a ____ pressure.
Low;high
211
What part of a safety relief valve contains the pressure that opens the valve?
A huddling chamber
212
A mechanism used to open or close a valve is called a?
Actuator
213
The maximum air pressure for pneumatic diaphragm actuators is approximately?
125psig
214
Which of the following devices is used to measure fluid pressure?
Bourdon tube gauge
215
Which of the following indicates flow rate by producing an electrical signal?
Turbine flow meter
216
Accumulators are used for?
Storing pressure
217
Applications that call for fully open or fully closed positions are best handled by a ____ valve.
Gate
218
The valve best suited for regulating flow is the ______ valve.
Angle
219
Which of the following valve materials is most best for use in high-pressure, high temperature conditions?
Steel
220
The marking "WOG" on the body of a valve stands for?
Cold water, oil, and gas
221
. Flanged joints require the use of ______ to create an effective seal?
Gaskets
222
One of the most common signs of insulation failure in steam lines is?
Leakage
223
Condensate in a steam tracing system should be drained to the?
Collection header
224
One of the disadvantages of electric tracers is that they?
Require constant monitoring
225
. The simplest way to protect an exposed water line from freezing is to?
Drain the line
226
Which of the following is an example of passive corrosion protection?
Installing a pipe liner
227
The machine operator frequently can give the troubleshooter?
Valuable information
228
Mechanical, hydraulic, and pneumatic systems all are worked on by the?
Mechanical troubleshooter
229
The purpose of good maintenance is to?
Keep machines and equipment working
230
A maintenance specialist reports to craft supervisors in all plant departments in a plant organized under?
Central organization
231
In a large plant, the building maintenance group is most likely to be made up of?
Electricians, Mechanics, Plumbers, Carpenters, and Painters
232
All communications is essentially a cycle of ____ steps.
Four
233
When you give a person a chance to express himself, you may?
Find him easier to work with
234
Writing down an order?
Helps prevent misunderstandings
235
Before you make a repair, you should?
Find out what your responsibilities are
236
If you have a problem or complaint about your job, you should?
Report it directly to the supervisor
237
If possible, you should schedule repair work for a time when?
The machine is not in use
238
Before you can diagnose problems, you must ?
Be able to recognize Normal operations
239
An ohmmeter measures?
Resistance
240
Air supplies should be checked?
When the machine is running
241
Your first duty in an emergency is to?
Protect workers from injuries
242
When should the troubleshooter check the machine drawings in the service manual?
Before working on the machine
243
Parts lists do NOT
Include a great deal of written technical information
244
High values of resistance can be measured with a?
Megohmeter
245
A bourdon tube is used to measure?
Pressure
246
Which of the following instruments measures the difference between two temperatures?
Thermocouple
247
The tools in your toolbox do NOT need to be?
New
248
When should you remove your lock from the machine controls?
After you have replaced the machine guards and covers
249
To recheck a system after making a repair, you should?
Run the system under both automatic and manual controls
250
Drive chains that run at speed of over 500 feet per minute require?
Constant lubrication
251
Which of the following conditions indicated conveyor overload?
Uneven spaces between the top plates of the conveyor chain
252
The diagram that shows both the external shape and the internal working parts of a system or a component is a?
Cutaway diagram
253
A piping system is shown in three dimensions in a?
Isometric diagram
254
A wiring diagram shows the?
Physical relationships of devices in an electrical system
255
Which of the following is used to trace the wiring in the ceilings and walls of a building?
Lighting diagram
256
Step-by-step instructions for testing equipment are included in a?
Troubleshooting chart
257
Modern precision-built bearings?
Help support power transmission shafts
258
Side-to-side movement of a shaft in a sleeve bearing should be no more than?
Two thousandths of an inch
259
NOT all centrifugal compressors have?
More than one air supply
260
Centrifugal, wet, and bag are types of?
Mechanical dust collectors
261
Synthetic coatings greatly improve the strength and resistance of a?
Floor
262
Electrical switchgear consists of?
Equipment that controls, protects, and regulates machinery
263
A panelboard is a small assembly that contains?
Either fuses or circuit breakers
264
Which type of diagram shows the parts of a circuit as they actually appear to the eye?
Pictorial
265
The basic unit for measuring electric current is the?
Ampere
266
Potential difference is measured with a?
Voltmeter
267
In a normal work-order procedure, which of the following jobs is done by the scheduler?
Issues the work order
268
Determining what parts and supplies are needed to make an emergency repair is the job of the?
Emergency crew
269
The best approach for identifying the cause of a breakdown in automatic machinery is?
The systematic one
270
The decision to run a machine part to the point of breakdown must be made?
Very carefully
271
Wear to machine parts caused by contact with chemically active materials is an example of?
Corrosion
272
The inspection and repair of plant equipment at regular intervals is called?
Planned maintenance
273
The work order form is used for?
Issuing instructions and obtaining feedback
274
Which of the following machine parts require daily lubrication?
Shafts and bearings
275
All of the following will cause a drive belt to deteriorate EXCEPT?
Too much ventilation
276
The sag in a drive chain should be about 1/4 in. for every ______ in. of distance.
12
277
The rotating weight of the unit is transferred through the trust bearing, though the upper bridge, and trough the _______ to the foundation.
Stator frame
278
On an umbrella unit, the thrust bearing is located?
Below the rotor
279
The three types of thrust bearings are?
Adjustable shoe, self equalizing and spring loaded
280
The adjustable shoe thrust bearing uses a ______ under each of the shoes for adjusting the height and loading of the shoes.
Jack screw
281
To install the thrust block, it is heated to a predetermined temperature and lowered over the shaft, again with the unit on jacks. The block is set on the _____. The rigging removed, and the radial keys and the keeper installed.
Thrust shoe
282
With the thrust block still hot and installed on the shaft, the jacks are released to?
Allow the full weight of the unit to set the block in place against the keys
283
Using the thrust bearing high pressure lubrication system, allows for both ____ and ____ movement required during the alignment process.
Rotational; lateral
284
As alignment deviates, loading on the guide bearings will increase a will ____ levels.
Vibration
285
Any increase in vibration from misalignment will decrease the ___ factor of operation in severe circumstances.
Safety
286
The concentricity of the stationary components can be checked by?
Hanging a single tight wire to check plumb reference
287
The tolerance for plumb center of shaft runout is ____ multiplied by the length of the shaft from the highest plumb reading to the lowest plumb reading in inches.
0.000025
288
The tolerance for shaft straightness should not be more than ____ inch from a straight line connecting the top and bottom reading point.
.003
289
The parallel misalignment between two shafts that occurs at the coupling between the generator and turbine shaft is called?
Offset
290
Shaft dogleg is?
Angular misalignment of the turbine and generator shafts
291
Plumb wires should be hung _______ apart.
90°
292
The first preliminary check during the alignment process, it to loosen the mounting bolts on each leg of the upper bridge to check for?
Soft foot
293
One of the most important things to check before taking alignment readings is to make sure the?
Shaft is free
294
The procedure that is particularly useful during major overhauls is to temporarily install the upper and lower bridges and the head cover to check the concentricity of the stationary components with a single plumb wire and a?
Electric micrometer
295
When the unit is centered the concentricity can be checked by taking _____ readings at the turbine guide bearings, seal rings, generator air gap, etc.
Clearance
296
Correcting dogleg between the generator and turbine shafts requires installing a shim pack between the?
Coupling faces
297
The second method used for aligning Hydrounits with adjustable shoe thrust bearings is using the adjustable feature of the shoes only to achieve equal?
Loading
298
On self equalizing thrust bearings, one step in the procedure is to center the shaft in the ________ housing and move the ______ of the shaft to make plumb.
Turbine bearing; top
299
The final step in the alignment process is the installation and adjustment of the?
Guide bearings
300
To make the generator guide bearings concentric to the turbine guide bearing, the _____ is used as a reference.
Shaft
301
When installing the turbine bearing, several ____ are used to prevent lateral movement.
Dowels
302
Although vertical hydrounit machines may be extremely large?
Close tolerances must be maintained
303
The vertical hydrounit machine that has the thrust bearing and upper guide bearing located above the rotor is called?
Suspended type
304
On large low-speed vertical hydrounit machines, the rotor poles are secured to the rim by?
Driven tapered keys
305
On an adjustable blade pump or propeller (kaplan) type turbine, a hollow shaft is required on the electrical machine to?
Allow oil pipes to be carried through the shaft from the oil head at the top of the unit to The turbine servomotor
306
On guide bearings, lubrication arrangements eliminate the need for an oil circulating system. The designated oil level is usually about ____ the length of the bearing above its lower end.
1/3
307
Brakes are usually operated by compressed air at ____ psi. When used as jacks, the brakes are operated by an oil pressure of ______psi.
75-100; 1000-3500
308
High pressure bearing lubrication is frequently used to reduce?
Break away Torque
309
The high pressure bearing lubrication pump assembly uses a _____ to prevent starting the machine (hydrounit) until the pressure is approximately 1000 psi.
Pressure switch
310
Prior to erection of the unit, the turbine or pump runner and shaft are centered and supported in a position at a specified distance usually ________inch below the correct operating position.
1/4 to 3/4
311
During the alignment process, fins should be provided on the plumb bob to allow it to hang in a pail of heavy oil to dampen any swings and protect the plumb line from?
All strong air currents
312
Electric welding on any part of the machine is a serious hazard to bearings. A bearing surface can be damaged?
Rapidly if welding current passes through it
313
In regards to hydrounits, if possible all electric welding should be done?
Before bearings are assembled
314
The thrust bearing tub cooling coil should be water-tightness tested to a water pressure of _______% of normal working pressure.
150
315
Precautions should be taken during assembly of the thrust bearings to avoid?
A.T.A.
316
Segmental bearings made up of independently adjustable segments must be set to?
Proper elevation and clearance
317
To eliminate the possibility of shaft current, bearings and other parts should be?
Insulated
318
Check the insulation with a _____ volt insulation meter, if the resistance is less thank ____ohms inspect the insulation and make necessary corrections
500; 20,000
319
Before drawing the couplings together, their mating surfaces must be in alignment, parallel, clean and free from burrs. The coupling must be drawn up?
Evenly to prevent distortion
320
Coupling bolt tension can be determined by an accurate measurement of the bolt?
Elongation
321
To prevent plumb wires from swaying and twisting, the finned weights should be immersed in pails of?
Oil
322
Check commutator _____ with a dial indicator rather than by visual observation.
Runout
323
Various instruments and relays and their associated equipment, wiring, piping and conduit should be carefully installed, making sure that it does?
No short Circuit the
| bearing insulation
324
The rotating parts of the machine must be in ____ balance and may require the addition of weights to the rotor.
Dynamic
325
Before connecting the generator to the power system check?
Phase sequence 
326
If an operational check of the shaft runout is required, make it after the generator?
Is operating under full load
327
In planning a major overhaul of a hydroelectric unit, one of the best sources of information is?
Maintenance records
328
Determining the condition of the equipment should be done by performing a thorough inspection of the unit?
6-12 months before planned overhaul
329
A list of _____ for all of the machines components should be made from the drawing information.
Weights
330
If substantial welding is needed, the a __________ for the required repairs should be written and distributed to all the personnel that will be involved in the welding.
Welding procedure
331
Units with replaceable seal rings should have a ______ onsite.
Spare set
332
Shaft runout readings, bearing temperatures, pressures and permanent magnet generator (PMG) voltages are all part oF?
Pre shutdown readings
333
Preteardown readings include?
Shaft alignment readings, guide bearing clearance, seal ring clearance, and generator air Gap
334
To make sure parts are installed in exactly the same position from which they are removed, they should be ________ prior to removal
Match marked
335
The rigging to lift the thrust block should include a ______ so that the block can be kept level to prevent binding when it is lifted off the shaft.
Turnbuckles
336
After removing thrust and guide bearings, minor scratches and even some deep gouges can be adequately repaired by ____ the high spots from the babbitt surface.
Scraping
337
In most cases the repair of ___ damage can be accomplished much more effectively with the runner removed from the turbine pit as the runner can be positioned for easier access.
Cavitation
338
Where an overlay of a dissimilar materials is being used such as stainless steel over mild steel ,enough material should be removed to allow at least ___ weld passes to be made.
Three
339
The interior bore of the packing box can be built up with ___ ___ as long as the box is structurally sound.
Epoxy coating
340
Bearing cooling coils should be thoroughly inspected and _______tested.
Hydrostatically
341
To fin the units center, the upper bridge and headcover should be installed after all the _______ parts have been removed. A _____ wire should be hung through the unit and reference measurements taken from the stator, the turbine bearing housing, the packing box bore, and to trammel points in the draft tube
Rotating; single
342
Dowels have a very ___ fit to prevent the components from shifting once the part is positioned.
Tight
343
When doweled components are moved during the alignment process following the overhaul of a unit _______, is necessary
Redoweling
344
A more accurate method of measuring the preload of a coupling bolt is to measure the amount the bolt ___ as the nut is tightened.
Stretches
345
When aligning a unit, it is important to make the bearing centers all ____, the shaft must be perfectly plumb. This can be accomplished by installing the turbine bearing and shimming the shaft to center in the _____ bearing(s)
Concentric; Turbine
346
When setting clearances on upper and lower guide segment show bearings, install a feeler gauge to check clearance by?
Inserting the feeler gauge so that it extends all the way through the bearing
347
When working on wicket gate adjustment the amount the servomotor travels after the gates contact each other is referred to as the?
Squeeze
348
There should be ___ leakage upon the initial startup after the installation of new turbine shaft packing. The packing gland should be ___ evenly and in small steps until the leakage is reduced sufficiently.
Generous; tightened
349
A very thorough inspection of the ___ ____ and the ___ ____ should be made to check for any bolts, nuts, tools, etc.
Generator housing; spiral case
350
to prevent the damage tat could occur from circulating currents passing through them the following are insulated from the frame and should be checked with an ohmmeter prior to startup.
Upper guide bearing, Thrust bearing, PMG
351
Operational readings should be taken once the unit has been determined to operate with no problems, they include?
Bearing heat run, Shaft runout readings, Load rejection tests
