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Millwright 2nd Year > Belts > Flashcards

Flashcards in Belts Deck (38):
0

What is the V belt minimum arc of contact

120°

1

what part of the V-belt carries the load

Tensile members

2

How does a V-belt transmit power

Friction between the sides of the belt and the sides of the sheave groove

3

The belt terminology "stretch" means what

Increase in length of the belt over the period of time that it is in service

4

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

5

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

6

It depends on the nature of the surfaces in contact

Coefficient of friction

7

Arc of contact is the number of "what" that about wraps around the Pulley

Degrees

8

What does tension on the belt determine

The force between the belt and the pulley

9

Classical series belts are recognized by what designation on the label

A, B, C, D and sometimes E

10

What are the four variations of the standard classical series belts

Cogged raw edge
banded
double V
and fractional horsepower

11

cogged raw edge are designated as....

AX, BX and CX

12

Double V belts are designated how....

AA, BB and CC

13

Fractional horsepower belts are designated how and are used for what kind of duty

2L,3L,4L,5L
Light duty

14

High-capacity belts are designated how

3V, 5V and 8V

15

On a high-capacity belt how is the designation measured in inches

3/8 inch
Ex 3V= 3/8"
Ex 8V= 1"

16

Poly V belts are also called V rib belts what are their designations

J, K, L and M

17

On poly V belts what is the designation H used for

Small sheaves and miniature drives

18

What kind of belt is used when the sheave is designed to open and close with speed changes

Variable speed belts

19

Variable speed belt what is the width measured in inches

Sixteenths of an inch

20

On an open-ended belt what is it's main advantage

They can be cut to any length and then be molded together

21

What is a main limitation of an open-ended belt

You can only carry one third of the load

22

Link Belts are only used for what

Emergencies

23

Round belts have a great advantage and are suitable for what kind of drives
Name two

Quarter turn and serpentine Drive's

24

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

25

What is the maximum misalignment you must not exceed "in inches" per foot of distance

A 16th of an inch per foot of distance

26

What Kind of tool should you used for belt tensioning

Belt deflection gauge

27

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

28

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

29

Synchronous belts cannot tolerate any what

Slippage

30

Synchronous belts are used for what kind of operations

Smooth
high-speed
very small radius drives
And short center to center distances

31

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

32

Round and trapezoidal teeth are for what kind of belt

Synchronous belts

33

What is the length and width of this synchronous belt
255L025

25.5" long
.25" wide

34

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

35

A Sprocket has what running across the rim

Grooves

36

What is the number of grooves and width of the sprocket code

24L050

24 grooves
1/2" wide

37

3 type of hubs

Web
Block
Arm