Belts, Chain, Gears test teacher Flashcards
what length of belt is required if the centre to centre distance is 51” and the small pulley is 10” and big pulley is 30 “ formula –( (D+d)/2 ) x pi + 2xc pi=3.1416 c=centre to centre distance
19’ 6”
17’ 8”
20’ 4”
13’ 9”
13’ 9”
a variable speed drive changes belt position from the top of the driver sheave to the bottom. this results in a
speed increase
speed decrease
no speed change
reverse of direction
speed decrease
.a v-belt code marked 5V 250 on the outside means
5/8” wide by 25” long
5/8” wide by 250” long
3/8” wide by 25 “ long
3/8” wide by 250” long
Option 5
5/8” wide by 25” long
the term used to describe the tension needed on a belt to transmit power without slippage is
effective tension
installed tension
equal tension
free tension
effective tension
v-belt drives achieve a tighter belt grip than flat belts due to the
area of contact
wedging action
efficiency of friction
arc of contact
weddgng action
positive drive belts (similar to chain drives) and must be used with
low loads and speeds
pulleys of the same pitch
small pulleys
all the above
pulls of the same pitch
polly v-belts are constructed by adding a cover backing to the top of 2 or more conventional belts
true
False
false
the standard crowm built into the a flat pulley is
1/8”/ft
1/16”/ft
1/3 of the belt width
1/96
both the first and 4th answers are correct
both the first and 4th answers are correct
the width of a pulley for a flat belt of a 7” width would be
8”
9”
10”
7”
9”
chirping is caused by
dust
over-tightened belts
idler pulleys
cocky students
dust
a sheave that has both A and B section grooves on it is known as a ______________
variable sheave
adjustable sheave
combination sheave
none of the above
combination sheave
belt storage for synthetic belts should be in a
cool and dry place
cool and humid place
damp and dark place
it does not matter
cool and humid place
variable speed sheaves are adjusted
slowly while stopped
while running
at rest
stopped and locked out
while running
linked v-belts are
used in an emergancy
used on sheaves that are mounted inside bearings
available in the smae power rating as standard belts by some manufacturers
all the above
all the above
if an idler is needed to increase the arc of contact on the drive pulley, you need to put the idler
inside near the driver
inside near the driven
outside near the driver
outside near the driven
outside near the driver
if the v-belt inside diameter is cracked, the most likely cause/s is
misalignment
the pulley diameter is to small
burning caused by excessive slip
both the 2nd and 3rd answers are correct
both the 2nd and 3rd answers are correct
the pitch line of a v-belt is at the
insulation area
tensile member
cushion layer
cover
tensile member
if an idler is added to the inside of a v-belt to tension it, the idler would
decrease the arc of contact
be a grooved or flat pulley
be put on the slack side at a point that produces equal arcs of contact on the sheaves
all the above
all the above
what could happen if you use never seize on the tapered surfaces of a tapered bushing and a cast sheave being mounted on a shaft
seize on the shaft
cause less friction on the shaft
break the pulley
nothing, this is what you are suppost to do
break the pully
why should you not depend on feel when checking the tension of the belt
everyone has a different feel for tension
tensile members of different strengths require different tensions
different belt manufactureres have differne standards
all the above
all the above
the amount of power that a v-belt can transmit depends on the arc of contact, tension applied and the coefficient of friction between the belt and pulley
true
false
true
slip is when creep of the belt increases to extend all the way around the pulley because of an increase in load
true
false
true
cogged raw edged belts
are designated by an x at the end
have good flexibility
have a high coefficient of friction
all the above
all th above
banded belts help stop belt turn-over
true
false
true
open-ended v-belts have a carrying capacity of__________ of that of an endless v-belt
1/4
1/3
3/4
there is no marked difference
1/3
if a new v-belt runs down in the groove, it is time to
change the hub
change the sheave
both the first and 2nd answers are correct
none of the above
change the sheave
if a v-belt has a cut bottom and side-wall, this indicates that the
belt was pried onto the sheave during installation
belt was oil-soaked
belt had a back-side idler
sheave was to large
belt was pried onto the sheave during installation
if a v-belt is found to have swollen in size, this is an indication of
belt exposed to water
belt exposed to oil
belt running in hot conditions
All the above
belt exposed to oil
when using a straight edge to check for sheave alignment, you should make sure the maximum misalignment does not exceed
1/16” per 6” of belt span
1/16” per foot of belt span
1/4” per 6” of belt span
1/4” per foot of belt span
1/16” per foot of belt span
if you find a banded belt having cuts thru the backing and the running in the bottom of the seave grooves, you should
add more backing
loosen off the tension
replace the sheaves and belt
check for proper belt material
replace the sheaves and belt
you are checking for _________ when you have a dial indicator reading off of one of the sheave groove faces
sheave rim runout
sheave damage
sheave runout
proper alignment of the sheave to the other sheave
sheave run out
when using a deflection gauge to check for proper telt tension, you need to set the force applied o-ring to 0 and the other o-ring to the proper deflection distance for that belt
true
false
true
quarter turn belts
a maximum speed ratio of 2.5 to 1
centre distance of 5.5 times the sum of the large sheave diameter plus its face width
its centre line of the horizontal shaft abov the centre line of the vertical shaft
all the above
all the above
before checking the belt for proper tension, you should always rotate the belt and sheaves a few turns
true
false
true
synchronous belts are timing belts
true
False
true
synchronous belts need _______ degrees of arc contact on the sprocket and _____ teeth engaged
120, 6
60, 8
60, 6
100, 8
60,6
if a belt is snaking from one sheave to the other while running indicates
sheave runout
sheave misalignment
shaft runout
all the above
all the above
standard belts are designed to run at a maximum of ____degrees Celsius
50
60
80
100
60
synchronous belts are about 98% efficient and need less tension then the standard v-belts
true
false
true
if you are using plastic sheaves, you are in a/an
highly abrasive environment
light duty installation
a high temperature environment
all the above
light duty installation
chain sprockets are describe by letters A,B,C,D. these refer to the hub_________
bore
class
size
diameter
class
the minimum amount a roller chain can be shortened is
1 link
1 pitch
1/2 pitch
2 links
1 pitch
a modified leaf chain that forms a tooth pattern when assembled is a
wrench chain
silent chain
vise chain
oil field chain
silent chain
a type D sprocket is of a___________ design
steel plate
split hub
hub 1 side
hub both sides
split hub
a chain designated #120-2 has a pitch of
3/4”
1 1/4”
1”
1 1/2”
1,1/2
the recommended lubrication system for drives of moderate speed and load is
manual
bath
pump with a stream flow
drip
bath