This document provides information about power transmission systems. It defines power transmission as the movement of energy from the place of generation to where it performs work. The main types of power transmission systems discussed are belt drives, rope drives, and chain drives. Belt drives can be flat belts, V-belts, or circular belts. Rope drives use either fiber or wire ropes. Chain drives use an endless chain running over gears. Different types of gears are also defined, including spur gears, helical gears, bevel gears, and internal/external gears.

1. Course Code : ME-2033
Course Title : Elements of theory of machine & machine design
Topic: POWER TRANSMISSION
Submitted To:
Ms. Zulfa Ferdous
Senior Lecturer, SEU
Submitted By:
Name: Naeeim Hasan
Id No: 2016000400025
Batch: 31st
Section: A

2. Contents..
 Definition of Power Transmission
 Types of Power Transmission
 Definition of Belt Drive
 Types of Belt Drive
 Definition of Flat Belt
 Types of Flat Belt
 Definition of V Belt
 Definition of Circular Belt
 Definition of Rope Drive
 Types of Rope Drive
 Definition of Chain Drive
 Definition of Gear
 Types Of Gear

3. Power Transmission
Definition of Power Transmission:
Power transmission is the movement of energy from its place of
generation to a location where it is applied to performing useful work.
Power is defined formally as units of energy per unit time. In SI units:
Watt =
𝑗𝑜𝑢𝑙𝑒
𝑠𝑒𝑐𝑜𝑛𝑑
=
𝑛𝑒𝑤𝑡𝑜𝑛 × 𝑚𝑒𝑡𝑒𝑟
𝑠𝑒𝑐𝑜𝑛𝑑

4. Types of Power Transmission
Types of Power Transmission:
 Belt Drive
 Rope Drive
 Chain Drive
Belt Drive:
A belt is a loop of flexible material used to link two or more rotating shafts mechanically, most often
parallel. Belts may be used as a source of motion, to transmit power efficiently, or to track relative
movement. Belts are looped over pulleys and may have a twist between the pulleys, and the shafts need
not be parallel.

5. Types of Belt Drive
Types of Belt Drive:
1. Flat Belt
2. V Belt
3. Circular Belt / Rope
Flat Belt:
The flat belt is mostly used in the factories and workshops, where a moderate amount of power is to be
transmitted, from one pulley to another when the two pulleys are not more than 8 metres apart.
V Belt:
The V-belt is mostly used in the factories and workshops, where a moderate amount of power is to be
transmitted, from one pulley to another, when the two pulleys are very near to each other.

6. Types of Flat belt Drives
Circular Belt / Rope:
The circular belt or rope is mostly used in the
factories and workshops, where a great
amount of power is to be transmitted, from
one pulley to another, when the two pulleys
are more than 8 meters apart.
Types of Flat belt Drives:
1. Open Belt Drives
2. Crossed or Twist Belt Drives
3. Quarter Turn Belt Drives
4. Belt Drives with Idle Pulleys
5. Compound Belt Drive

7. Types of Flat belt Drives continue..
Open Belt Drives:
In an open belt drive, shafts are arranged in
parallel and rotate in the same direction. The
driver pulls the belt from the lower side and
delivers it upper side of the pulley so that
lower side is always tight and slack is on the
top side.
Crossed or Twist Belt Drives:
Cross belt, also known as the twisted belt, is twisted
as shown fig. In a cross belt drive, the shafts are
arranged in parallel, and twisted arrangement makes
pulleys rotating in the opposite direction. The speed is
limited to 15m/s to avoid excessive wear. Both sides
of the belt get contact with pulleys, so this
arrangement not advisable for V-Belt and Timing Belt.

8. Types of Flat belt Drives continue..
Quarter Turn Belt Drives:
Also known as the right angle belt drive. In
this type, shafts are arranged at right angles.
Belt Drives with Idle Pulleys:
Also known as the jockey pulley drive. Idler pulleys
are pressed against the belt and guide them. They
change direction and increase the angle of contact. It
can provide a high-velocity ratio. Idler pulleys can also
reduce the vibration in the belt.

9. Rope Drives
Compound Belt Drive:
Compound belts are similar to open belt
drive. They used to power transfer through
one or more intermediate pulleys.
Rope Drives:
Ropes were used as belts for the transmission of power before
belts became common. Because of the low coefficient of
friction between the rope and the pulleys, multiple loops were
usually used, either as a single rope passing several times
around the pulleys, or multiple ropes on the same pulleys. The
advantage of multiple ropes is that if one fails, the others will
continue to transmit power.

10. Types of Rope Drives
Rope drive are two types:
1. Fiber Ropes 2. Wire Ropes
Fiber ropes:
These ropes can use at a distance up to 60m. Fiber ropes are commonly made of hemp, manila, or cotton. The ropes
made from hemp and manila are not flexible and have inferior mechanical properties compared to the cotton.
Wire ropes:
They used for power transmission over a large distance (they can transmit power over 150m). These are usually
employed in an elevator and cranes. The wire ropes are made from twisting steel wires (other alloys used for special
application).

11. Chain Drive
Chain Drive :
An endless chain running over toothed wheels mounted on the driver and driven shafts. The smaller
wheel is called pinion and the other is called wheel. The chain consists of plates; pins and bushes made
of high-grade steel. There are hoisting chains and pulling chains apart from the power transmitting
chains. Roller chains and silent/inverted chains are the different types of power transmitting chains.

12. Gear
Definition of Gear:
A gear is a toothed cylindrical or roller shape component of a machine which meshes with
another toothed cylindrical to transmit power form one shaft to another. It is mainly used to
change in torque and speed of driving shaft and driven shaft.
Classification of Gear:
1. According to the position of axes of the shafts.
 Parallel
Spur Gear: The most common and easy to produce parallel shaft
cylindrical gears. Of a pair of gears, the larger one is called a gear and
the smaller one a pinion.

13. Classification of Gear
Helical Gear: Quiet and able to transmit larger torque than spur gears. Cylindrical
gears with spiral shaped tooth trace.
 Intersecting
Bevel Gear: Cone shaped gears used in intersecting shaft applications. There are also
bevel gears with spiral shaped tooth trace called spiral bevel gears.
 Non-parallel:
Screw Gear: Used in offset shaft application. Shape wise, they are the
same as helical gears.

14. Classification of Gear cont…
2. According to the Peripheral Velocity:
Low velocity gears: If the velocity is less than 3 m/s
Medium velocity gears: If the velocity is between 3-15 m/s
High velocity gears: If the velocity is above 15 m/s
3. According to the type of Gearing:
Internal gear: Gear teeth are cut on the inside surface of hollow cylindrical forms
and used in planetary gear systems. The gear teeth are cut using gear shaper machines.
External Gear: External gear is mesh externally with each other. The motion of two
Wheel is always opposite direction.

15. Classification of Gear cont…
 Rack and Pinion: Rack and pinion gears are used to convert rotation (From the pinion) into linear
motion (of the rack).A perfect example of this is the steering system on many cars

16. Thanks To All