design of hartnell governor

1. Design of hartnell governor
A
PROJECT REPORT
Submitted by
VISHAL KUMAR (14200713054)
DEBOJYOTI BISWAS(14200714064)
Is partial fulfilment for the award of the degree
Of
BACHELOR OF TECHNOLOGY
In
MECHANICAL ENGINEERING

2. BONAFIDE CERTIFICATE
This is to certify that a project report on “ Design of Hartnell Governor ” is the
bonafide work of “ Vishal Kumar, Debojyoti Biswas ” who carried out the project
work under my supervision.
During this period of project in MSIT, Kolkata, their conduct was found
good & satisfactory. They took keen interest in the project & was found to be most
sincere, hardworking & having potential to be a good executive. This document is
a bonafide testimony of the training undergone by him in this course.
We wish them success in their future.
GOUTAM LAHA ARIJIT CHOUDHURY
HEAD OF DEPARTMENT ASSITANT PROFESSOR
MSIT, KOLKATA MSIT, KOLKATA

3. CONTENTS
TOPICS Page No

4. ACKNOWLEDGEMENT
In the successfulaccomplishment of our project , we have had the supportof many
people . we would like thank the almighty at first and then we would like to share
our deepestgratitude towards our respected teacher , MR. Arijitchoudhury
because of his constant guidance and association with us during the courseof this
project which has been most pleasurable experience . Without his help and counsel
, Always generously and unstintingly given, the completion of this work would
have been immeasurably more difficult.
We would also like to take this opportunity to show our gratefulness towards our
parents and friends who supported us throughout our project and always lend their
helping hands.
Thank you everyone.

5. INTRODUCTION
A governor, or speed limiter, is a device used to measure and
regulate the speed of a machine, such as an engine. A classic example is
the centrifugal governor, also known as the Watt or fly-ball governor on a
reciprocating steam engine, which uses the effectof centrifugal force on

6. rotating weights driven by the machine output shaft to regulate its speed by
altering the input flow of steam.The function of governor is to regulate the
speed of an engine when there are variation in the load.
TYPES OF GOVERNOR:
The governors may broadly be classified as
1) Centrifugal governors .
2) Inertia governors.
The centrifugal governors may further be classified as follows:

7. DIFFERENCE BETWEEN GOVERNOR AND FLYWHEEL:
Sr. No. Flywheel Governor
1.
Maintains constant speed
but the means is different
from that of Governor.
Stores excess of
rotational energy from
Maintains constant speed but
the means is different from that
of Flywheel.
Controls mean speed of the
engine under full/half/varying

8. the power stroke and
supply back during non-
power strokes of the
cycle
load conditions by regulating
the supply of working fluid to
the engine
2.
In this, there are energy
variations but runs the
crankshaft at constant
speed in each stroke of
the cycle
When load on the engine
increases, speed decreases. It
increases the flow of fuel to
keep the constant mean speed
3.
Flywheel controls the
speed for one cycle only
Governor maintains constant
mean speed over a period of
time.
4.
Flywheel is not required
in all the prime movers
(engines)
Governor is required in all the
prime movers (engines)
5.
It is a heavy machine
part
It is a relatively light machine
part
6.
Has large moment of
inertia
Relatively small moment of
inertia
7. Rotating part Non- Rotating part
8. Running charges are less Running charges are high
9.
Angular speed increases
while storing energy and
decreases during supply
back of energy
Runs at mean speed under all
loads on the engine
10.
Crankshaft runs at
constant speed
Load increases speed decreases
and vice -varsa. But it controls
the MEAN speed by controlling
the flow of fuel in the engine
11.
There are no valves
attached with the
Valves are there and there
opening is controlled by the

9. flywheel centrifugal force on the balls
attached
12.
Flywheel does not need any
extra mechanism to supply
back energy
Governor needs a piston
/plunger mechanism
13.
It absorbs energy from the
high momentum generated
in power stroke and engine
running smoothin non
power strokes
It controls the air supply to
the carburetor and fuel
supply to the engine
14.
It is connected to the crank
shaft and runs it at a
constant speed
It is not connected to the
crankshaft
15.
It is an energy storing
device and prevents the
fluctuations of energy
during each cycle of
operation of the engine.
It is not an energy storing
device.
16.
It is a wheel and only its
size may differ from one
machine to another
There is a large variety of
governors used in different
prime movers
17.
Flywheel is a fairly rigid
structure and undergoes no
changes while in operation
A governor undergoes
changes while in operation
18. Short term energy storage
A long term speed controller
as per load on the prime
mover
19.
Used in reciprocating steam
and IC engines
Used in riveting machines to
store energy from the motor
and release the energy during
the riveting operation Used
in SI and CI engines

10. 20.
It cannot change the speed
of the crankshaft It is used to limit the speed.
21.
Flywheel supply back
energy as when required
Power is supplied to the
governor from the engine
shaft
22.
Energy stored in a flywheel
is directly proportional to
the square of its rotational
speed There is no such relation
APPLICATION OF GOVERNOR:
A governor helps to maintane the required constant speed
of any device with the help of centrifugal force , in automobiles itcontrols
the speed and keeps the speed within the pre desired speed byoperating
the throttle valve. Its application also involves in speed controlof
TURBINE shaft in Hydroelectric power plants since the varying water
pressure may increase or decrease the speed,the governor operates the

11. water nozzle. Governors were also used in speed controlof
mechanical MUSIC BOX.
A) Mechanicalmusic box:
B) Automobile:

12. c) Powerplant:
ADVANTAGES OF GOVERNOR:

13.  They are inexpensive.
 They are satisfactory when it is not necessaryto maintain exactly the
same speed, regardless ofload.
 They are extremely simple with few parts.
DISADVANTAGES OF GOVERNOR:
 They have large deadbands,since the speed-measuring device must
also furnish the force to move the engine fuel control.
 Their power is relatively small unless they are excessivelylarge.
 They have an unavoidable speed droop,and therefore cannot truly
provide constant speed when this is needed.
DEFINATIONS:
• Speed drop
A progressive drop in speed as load is picked up by the prime mover
from no load to full load without manually changing the speed setting
of the governor. It may be expressedin percentage and is equal to no
load rpm minus full load rpm divided by full load rpm times 100.
• Sensitivity
The smallest speed change that will induce the governor to alter the
fuel flow. A sensitive governor will give a large movement of the
control sleeve for only a small change in the radius in which the
flyweights are revolving.
• Stability
The ability of the governor to correcta speed disturbance with a
minimum of false motions. As the governor becomesmore sensitive it
becomes less stable.
Compensation:

14. A mechanical and/or hydraulic action that prevents over correctionof
the fuel supply is called compensation.Compensationin a governor
produces transient speed droop i.e. a momentary speed droop during
a speed correction.
• Dead band:
A narrow band of speed variation through which the governor makes
no correctionof fuel supply.
• Hunting:
When the load on an engine changes the governor tends to over-
control or under-control. This causes a fluctuation in rpm, which is
called hunting. For example, if load is removed from an engine, the
speed increases some amount above normal and the governor
comes into operation and reduces fuel supply. Due to friction and
time lag, the governor causes the fuel reduction to be in excess of
that required and the fall in speed is too much. This causes the
governor to increase fuel and the engine rpm goes slightly above
normal. This swing in speed above and below the mean operating
rpm for that load continues until equilibrium is reached and hunting
ceases.The more sensitive a governor is, the greater will be the
tendency to hunt.
• Isochronous:
Constant speed i.e. the same average speed regardlessof load.
HARTNELL GOVERNOR

15. INTRODUCTION OF HARTNELL GOVERNOR:
It is a Spring loaded Governor. It has two bell crank levers carrying fly
ball at one end and roller attached to other end, the function of spring
is provide the counter force which acts against centrifugal force.The
spring and shaft is enclosed inside a casing .The sleeve is pressed
against the spring when the centrifugal force on the balls increases.
Due to spring return nature this governor can be mounded in
horizontal , inverted, (inclined) position.
WORKING PRINCIPLE OF HARTNELL GOVERNOR:

16. A Wilson-hartnell governor is also a spring loaded type governor. In this
governor, the balls, which are mounted on vertical arms of bell crank lever
are connected by two radial springs as shown in above figure. These
springs control the centrifugal force of the balls. In this governor, the initial
tensions in the radial springs are not adjustable, so an adjustable auxiliary
spring is used which is connected to sleeve through a lever. When the
speed of engine increases,balls try to fly out and sleeve moves upward
causing tensions in radial springs.The auxiliary springs tries to bring the
sleeve down.
DESIGN OF HARTNELL GOVERNOR:
This is a governor with a spring so we will examine this to see how the
spring affects the controlling force.The balls of mass 'm' are carried on a
bell crank with arms of length A and B as shown. The sleeve is held down
against the crank by a spring that can be adjusted. As the balls fly outwards
under centrifugal force the sleeve is raised and compressesthe spring. As
the sleeve moves the radius of the balls from the axis of rotation 'R' will
change and so the weight of the ball comes into play either adding to the
spring force or reducing the spring force depending which way they move.

17. GEOMETRY:
When the crank is at the mid point it is horizontal and vertical. xO is the position
of the sleeve and RO is the radius of the balls. Rotating the crank θ the sleeve
moves to position x and the balls to radius R.

20. REFERENCE:
 Theory of machines by R.S Khurmi
 InternationalJournal for Research in Business, Managementand
Accounting ISSN : 2455-6114
 InternationalJournal of Scientific and Research Publications, Volume 2,
Issue 6, June 2012
 Wikipedia
 Quora
 ask.com