# Belt Drive and its Types

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Today we will discuss about belt drive and its types. We all know that belt drives are used to transmit power form one shaft to another, which have not common axis. In the fact belt drive is used to transmit power. One alternate of belt drive is gear drive but gear drive is not economical when large distance between driving and driven shaft. Belt drive is very popular in power transmission due to its lower cost and high performance. They are used in many industries. The main principle of belt drive is friction. The power transmission between shaft is depend on friction between belt and pulley.

The amount of power transmitted depends upon the following factors :-
1. Velocity of belt
2. Tension under belt placed on pulleys
3. Arc of contact between thee belt and the smaller pulley

Factor consider while selecting belt drive:-
1. Speed of the driving and driven shaft
2. Speed reduction ratio
3. Power to be transmitted
4. Center distance between shafts
5. Shaft layout

## Types of belt drives:-

### According to power transmitted

#### 1. Light drives:

These are used to transmit small power at belt speed up to about 10m/s. It is usually used in agricultural machines and small machine tools.

#### 2. Medium drives:

These are used to transmit medium power at belt speeds from10m/s to 22m/s. It is used in machine tools.

#### 3. Large drive:

These are used to transmit large power at belt speeds above 22 m/s. These are used in compressor, generator and heavy machinery.

### According to the arrangement of belt:

#### 1. Open belt drive:

These belt drive used with shaft s arranged parallel and rotating in same direction. In this drive the driver pulley pulls the belt from one side and delivery it to the other side. Thus the power is transmitted form driver pulley to driven pulley. The tension in the lower side of the belt is more than the upper side. So the lower side is known as tight side and upper side is known as slack side.

#### 2. Crossed belt drive:

This belt drive is used when shafts are parallel to each other but rotating in opposite direction. In this case the driver pulls the belt form one side and delivers it the other side. In this drive tension is more on that side where driver pulls the belt, so this side is known as tight side and other is known as slack side.

#### 3. Quarter turn belt drive:

This belt drive is also known as right angle belt drive. This drive is used when shafts arranged at right angles and rotating in one definite direction. To prevent the leaving the belt in this drive the width of face of pulley is 1.4 times greater that the width of belt.

#### 4. Compound belt drive:

A compound belt drive is used when power is transmitted on more than one shaft. In this arrangement power is transmitted form one shaft to another through a number of pulleys.