Power Transmission Flashcards
Calculate the accurate belt length for the following: The large diameter pulley is 11.25” and the small diameter pulley is 6.125” shaft centers are 17.5” apart.
62.28
D+d/2 × Pi + (2×c)
The clearance of meshing gears of any diametral pitch is known as what?
Back Lash
A Babbitt bearing percentage refers to its area of contact. This is found by what method?
Bluing
A bearing with a ‘K’ denotes a tapered bearing. This is held in place by what method?
A tapered adapter sleeve
An 8” pulley turns at 120 RPM and drives a second pulley at 150 RPM. What is the driven pulley diameter?
6.4” (high over low)
The letters A, B, C on a sprocket refers to what?
Hub Class
What is crowning on a pulley used for?
Self alignment
The standard taper on an Imperial key is what?
1:96
A type of bearing mounted face-to-face and back-to-back is called what?
Angular contact
A bearing with a code of SFK 6212 has a bore of ?
60mm (last 2#s + 48)
A belt is wrapped around a 6.25” pulley and has 220ﾟ of contact. How much of the belt is contacting the pulley? (Use 3.14159 for pi)
11.999” (High over low)
A #60 chain has a pitch of what?
3/4”
In a number 65 chain, the 5 refers to what?
That the chain is roller-less
A drive system has 2 pulleys. The drive pulley is rotating at 120 RPM, and the driven at 150 rpm. The driven pulley is 6.4” in diameter. What is the diameter of the drive pulley?
8” (high over low)
Roller thrust anti friction bearings carry what type of load?
Axial
What do you use to check the clearance of a spherical roller bearing?
Feeler gauge
What type of coupling connects 2 shafts at slight angles?
U-joint
What temperature (in Fahrenheit) is a bearing to be heated to in an oil bath, prior to installation?
248 - 250 degrees F°
What temperature ( in Fahrenheit ) is Babbitt poured at?
650 - 700 degrees F°
(370°C)
What is the best method of belt joining?
Vulcanizing
What is creep in a belt caused by?
Elasticity
What is creep in a bearing?
The very slow rotation of the outer race
What principle do timing gears use?
Gear tooth
A gear tooth with a large pressure angle is said to be what?
Stronger
What are gib joints bearing suited for?
Limited side loading
High speed bearings and roller chain use what type of lubrication?
Mist
How much oil is required to lubricate a ball bearing?
Enough to cover halfway up the bottom rolling element
What is the breaker ply of a belt?
Layer under the carcass to absorb shock
What do you use to carry fines on a conveyor?
Camber slide
In a multi-bearing system, how many bearings are fixed?
Only one of them
To change the direction of travel on a conveyor, you would use a what?
Bend pulley
The approximate efficiency of a drive chain is what?
98%
What is the pitch of a # 80 chain?
1”
What is the overall length of a V belt specified in?
Pitch diameter
Where should the lubricant entry on a bearing be located?
On the low pressure point
What is the housing of a friction bearing called?
Pillow block
A Conrad bearing is what type of bearing?
ball bearing
A clearance fit means what?
Parts fit together easily
Oil grooves in a Babbitt bearing are located where?
In the unloaded section
What is a shielded bearing?
Is metal covers the rolling elements, sealing in the lubricant
What is a rigid coupling used for?
Joining 2 lengths of a shaft
A 60:1 gearbox is driven by a 1750 rpm motor. What is the output speed?
29.166 (÷by 60)
What is a Cooper bearing?
An anti friction bearing with the components in halves
When is a variable speed drive adjusted?
When the drive is running
How are gearboxes lubricated?
Splash method
Under what conditions are silent chains used?
High speed loads
The part of a belt that transmits power and carries the load is called what?
Carcass
A pulley used to increase arc of contact on the drive pulley is called what?
Snub pulley
How are turns attained in conveyor systems?
Tapered rollers
Friction bearings are what in relation to the shaft?
Softer than the shaft
What type of bearing uses the shaft as the inner race?
Needle
What type of bearing is suitable for high speeds?
Ball
The taper ratio of a tapered bearing is what?
1:12
A tapered bearing has what letter at the end of its code?
K
A bearing in a gearbox, subject to splash lubrication is called what?
Open
What is the bore of an SKF 6106 bearing?
30mm
When an anti friction bearing is fitted on a shaft in a fixed position, how is it held in place?
Stabilizer rings
The best way to remove a bearing from a shaft is to use a set of pullers with the strain applied to wear?
The inner race
Anti friction failure usually occurs due to what?
Contamination
When mounting a pair of angular contact bearings, the best technique is what?
“O” arrangement (face to face)
A short piece of material used to take up the space of the shaft when pouring Babbitt is called what?
Mandrel
Why must you remove water in a bearing assembly prior to pouring Babbitt?
It will cause blow back
What prevents a Babbitt bearing from rotating?
Dovetail grooves
In a Babbitt bearing, the corners of the bottom half must be what?
Relieved
When precision shells are installed, they will extend past the face of the bearing housing. This is called what?
Crush
A bearing is selected based on what?
Equipment requirements
Herring bone gears have what?
A formed point at the gear center
The distance a worm moves forward when making one complete revolution is called what?
Lead
The pitch circle of a gear may also be called what?
Pitch diameter
The gear ratio of a single reduction worm gear is determined by the number of teeth on the gear and what other factor?
Number of threads on the worm
The portion of tooth above the center line is called what?
Addendum
Hypoid gears have significant sliding action between meshing teeth. This is counteracted by what?
Using EP lubricant
A drive gear with 40 teeth turns at 200 RPM. The driving gear has 25 teeth. How many RPM is the driven gear turning at?
320 RPM (High over low)
A drive gear with 25 teeth turns at 500 RPM. The driving gear has 75 teeth. How fast is the driven gear turning?
166.66 RPM (high over low)
The term offset or half link alters a chain by what?
One pitch
What type of shaft alignment is to be checked 1st?
Angular
A jaw and slider has how many parts?
3
When using a chain type coupling, the chain is covered by what?
Shroud
The insert between coupling halves is called what?
Spider
Dry fluid couplings are preloaded with shot called what?
Flow charge
The standard size of a V belt is given in letters. The letters refer to what?
The sectional area of the belt
When multiple belts are connected to form one belt, this is called what?
Power bands
The pitch line of a timing belt is located on what part of the belt?
Neutral line
Where is belt tension checked?
On the tight side
The term given to the amount of power a belt can transmit is related to what?
Area of contact
A belt drive has a 10.125” and 6.625” pulleys. The center line distance is 12.375”. What is the accurate belt length?
51.29”
What is the best type of belt material?
Polymers
What is a notched V belt used for?
High speed drives with short centers
What is the function of a serpentine belt?
Drive on both sides of the belt
Rim speed is the ft/min measured on the outside of the pulley. With a 6.25” pulley running at 2450 RPM what is the rim speed?
4000 ft/min
The ratio of crowning of a roller relative to the face width is what?
1:96
How do you check for wear on the main bearings in a diesel truck?
Plastic gauge
If a single inlet fan has too much axle movement, what action is to be taken?
Lock the bearing furthest from the fan
A motor turns at 1000 RPM. This requires 1.5 horsepower. What is the horsepower at 1500 rpm?
2.25 HP
What type of engine has the highest compression ratio?
Diesel
A drive chain is riding at the top of the teeth on a sprocket. This is caused by what?
Worn-out sprocket teeth
How do you know if a bearing is tight enough on a sleeve?
Slight drag on the bearing
What type of impeller is best for slurries?
Closed Impeller
What part of a steam turbine wears out 1st?
High pressure areas due to wet steam
What type of worm gear gets rid of reverse?
Quadruple
What type of impeller uses hydraulic balancing?
Semi closed
How are pistons lubricated?
Oil holes
In a bearing, what happens if you use soft grease?
Higher temperature
What would cause a belt to turn over in a sheave?
Missalignment
What causes a V belt to obtain shiny sides immediately following installation?
Wrong Sheave
What causes drifting on a conveyor?
Misaligned idlers
What is the best set screw arrangement for maximum holding power?
12 and 9
What causes an amp drop on the motor of a vacuum system?
Blocked Inlet
What is the term given for a motor that runs at a speed where vibration occurs?
Critical speed
What is the function of a jacking pump in a steam turbine?
Allow oil to circulate prior to rotation
If you have a shaft with the diameter of 3.125” and is tapered down to 1.250” over a length of 7.525” what is the taper per foot?
2.99”
A belt drive has pulleys of 9.6875” and 6.255”. The center distance is 28.375”. What is accurate belt length?
81.88”
An anti-friction bearing is to be heated in an oil bath at 250ﾟ. The inside diameter of the bearing is 3.5”. What is the bore size after the heating? ( Room temperature is 70ﾟ)
3.501134”
What prevents a bearing from seating on a shaft against the shoulder?
Burrs on the shoulder
What best describes how hypoid gears operate?
Operate at non-parallel, non-intersecting axes
What would cause a chain to ride on top of a sprocket?
Chain stretched
How does a labyrinth seal work?
Non contact seal that permits liquid to be forced through centrifugal force to the outside of its grooves
Tapered roller bearings permit what types of loads?
Permit axial and radial loads
How is a belt adjusted that is running out to one side?
square up head and tail pulleys
How are hydraulic jacks stored?
Fully retracted in the vertical position
What is the primary purpose of a Woodruff key?
Avoid having a machine too much metal away from stressed areas of shaft
How many teeth on a driven spur gear will create a 2:1ratio when the drive gear has 90 teeth, and the idler has 10 teeth?
45 tooth
What type of maintenance is an oil change?
Preventative
What percent of a chain is left slack on a chain drive set up?
4%
What causes a heat exchanger to leak internally?
Gasket ripped
Bearing wear on start-up is caused by what?
Lack of oil wedge
