Belts Flashcards Preview

Millwright 2nd Year > Belts > Flashcards

Flashcards in Belts Deck (38)
Loading flashcards...
0
Q

what part of the V-belt carries the load

A

Tensile members

1
Q

What is the V belt minimum arc of contact

A

120°

2
Q

How does a V-belt transmit power

A

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

3
Q

The belt terminology “stretch” means what

A

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

4
Q

The belt terminology “creep” means what

A

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
Q

What kind of problems would “slip” give you

A

Power loss between the driver and driven
belt and sheave groove wear
extra heat which degrades the belt material

6
Q

It depends on the nature of the surfaces in contact

A

Coefficient of friction

7
Q

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

A

Degrees

8
Q

What does tension on the belt determine

A

The force between the belt and the pulley

9
Q

Classical series belts are recognized by what designation on the label

A

A, B, C, D and sometimes E

10
Q

What are the four variations of the standard classical series belts

A

Cogged raw edge
banded
double V
and fractional horsepower

11
Q

cogged raw edge are designated as….

A

AX, BX and CX

12
Q

Double V belts are designated how….

A

AA, BB and CC

13
Q

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

A

2L,3L,4L,5L

Light duty

14
Q

High-capacity belts are designated how

A

3V, 5V and 8V

15
Q

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

A

3/8 inch
Ex 3V= 3/8”
Ex 8V= 1”

16
Q

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

A

J, K, L and M

17
Q

On poly V belts what is the designation H used for

A

Small sheaves and miniature drives

18
Q

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

A

Variable speed belts

19
Q

Variable speed belt what is the width measured in inches

A

Sixteenths of an inch

20
Q

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

A

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

21
Q

What is a main limitation of an open-ended belt

A

You can only carry one third of the load

22
Q

Link Belts are only used for what

A

Emergencies

23
Q

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

A

Quarter turn and serpentine Drive’s

24
Q

If you have a belt that was cut at the bottom and sidewall what would be the cause of this kind of damage

A

Pryed over the sheave and damaged during installation

25
Q

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

A

A 16th of an inch per foot of distance

26
Q

What Kind of tool should you used for belt tensioning

A

Belt deflection gauge

27
Q

What are three things that idler pulleys do on belt driven systems

A

They increase belt tension
increase the arc of contact
and prevent belt whip

28
Q

What is the difference between inside and outside idler pulley

A

An inside idler pulley decreases the arc of contact

Outside idler pulley provides tensioning for the belt

29
Q

Synchronous belts cannot tolerate any what

A

Slippage

30
Q

Synchronous belts are used for what kind of operations

A

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

31
Q

What is the minimum arc of contact and how many teeth should be on the sprocket of a synchronous belt

A

60° and a minimum of six teeth

32
Q

Round and trapezoidal teeth are for what kind of belt

A

Synchronous belts

33
Q

What is the length and width of this synchronous belt

255L025

A

25.5” long

.25” wide

34
Q

What is the difference between a pulley and a sheave

A

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
Q

A Sprocket has what running across the rim

A

Grooves

36
Q

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

24L050

A

24 grooves

1/2” wide

37
Q

3 type of hubs

A

Web
Block
Arm