Belts Flashcards
what part of the V-belt carries the load
Tensile members
What is the V belt minimum arc of contact
120°
How does a V-belt transmit power
Friction between the sides of the belt and the sides of the sheave groove
The belt terminology “stretch” means what
Increase in length of the belt over the period of time that it is in service
The belt terminology “creep” means what
Loss of driving speed due to the lengthening and shortening of the belt as it cycles from the slack side to the tight side
What kind of problems would “slip” give you
Power loss between the driver and driven
belt and sheave groove wear
extra heat which degrades the belt material
It depends on the nature of the surfaces in contact
Coefficient of friction
Arc of contact is the number of “what” that about wraps around the Pulley
Degrees
What does tension on the belt determine
The force between the belt and the pulley
Classical series belts are recognized by what designation on the label
A, B, C, D and sometimes E
What are the four variations of the standard classical series belts
Cogged raw edge
banded
double V
and fractional horsepower
cogged raw edge are designated as….
AX, BX and CX
Double V belts are designated how….
AA, BB and CC
Fractional horsepower belts are designated how and are used for what kind of duty
2L,3L,4L,5L
Light duty
High-capacity belts are designated how
3V, 5V and 8V
On a high-capacity belt how is the designation measured in inches
3/8 inch
Ex 3V= 3/8”
Ex 8V= 1”
Poly V belts are also called V rib belts what are their designations
J, K, L and M
On poly V belts what is the designation H used for
Small sheaves and miniature drives
What kind of belt is used when the sheave is designed to open and close with speed changes
Variable speed belts
Variable speed belt what is the width measured in inches
Sixteenths of an inch
On an open-ended belt what is it’s main advantage
They can be cut to any length and then be molded together
What is a main limitation of an open-ended belt
You can only carry one third of the load
Link Belts are only used for what
Emergencies
Round belts have a great advantage and are suitable for what kind of drives
Name two
Quarter turn and serpentine Drive’s
If you have a belt that was cut at the bottom and sidewall what would be the cause of this kind of damage
Pryed over the sheave and damaged during installation
What is the maximum misalignment you must not exceed “in inches” per foot of distance
A 16th of an inch per foot of distance
What Kind of tool should you used for belt tensioning
Belt deflection gauge
What are three things that idler pulleys do on belt driven systems
They increase belt tension
increase the arc of contact
and prevent belt whip
What is the difference between inside and outside idler pulley
An inside idler pulley decreases the arc of contact
Outside idler pulley provides tensioning for the belt
Synchronous belts cannot tolerate any what
Slippage
Synchronous belts are used for what kind of operations
Smooth
high-speed
very small radius drives
And short center to center distances
What is the minimum arc of contact and how many teeth should be on the sprocket of a synchronous belt
60° and a minimum of six teeth
Round and trapezoidal teeth are for what kind of belt
Synchronous belts
What is the length and width of this synchronous belt
255L025
25.5” long
.25” wide
What is the difference between a pulley and a sheave
A pulley will transmit its power from its rim to the belt
A sheave is a pulley with a groove that runs around the circumference of the rim
A Sprocket has what running across the rim
Grooves
What is the number of grooves and width of the sprocket code
24L050
24 grooves
1/2” wide
3 type of hubs
Web
Block
Arm
