This document discusses governors used to regulate engine speed. It provides classifications of governors and describes their key characteristics, including stability, sensitiveness, controlling force, and isochronism. Specific governor types are also outlined, such as the Porter governor, Hartnell governor, and centrifugal shaft governor. The working principles of centrifugal and inertia governors are explained, and their differences are compared.

1. BULE HORA UNIVERSITY
COLLEGE OF ENGINEERING AND TECHNOLOGY
DEPARTMENT OF MECHANICAL ENGINEERING
COURSE TITTLE: MECHANISMS OF MACHINERY
COURSE CODE : MEng3071
GROUP ASSIGNMENT
NAME ID
1.ARESAWM WALTAW .................................................................................................................................................................................................. RU1826/12
2.DESALEGN DAGIM..........................................................................................................................................................................................................RU0361/12
3 . MEKIDES ASCHALE...................................................................................................................................................Ru0581/12
4 MAHILET MENGESHA..........................................................................................RU1439/12
5.ALELIGN SHIMELIS..........................................RU2381/12
SUBMITTED TO TESFAYE SUBMISSION DATE 26/5/2014E.C

2. content page
• introduction;..........................................................................3
• classifications of governors;.......................... ......................4
• governor characteristics;........................................................5
stability..............................................................................5
sensitiveness....................................................................5
controlling force.................................................................6
isochronism.........................................................................7
hunting...............................................................................7
• porter governor;.........................................................................8
• hartnel governor;.......................................................................9
• centrifugal shaft governor;.........................................................10
centrifugal governor working......................................................11
• inertia governors;.........................................................................12
difference between centrifugal anf inertia governor.......................14

3. Introduction
• the function of a is to regulate the speed of an engine, when there are variation
in in the load.e.g. when the load on an engine increases, its speed decreases, therefore
it becomes necessary to increase the supply of working fluid.on the other hand
• when the load on the engine decreases,its speed increases and thus less working fluid is
required.
• the governor automatically controls the supply of working fluid to the engine with the
varying load condition and keeps the mean spead within certain limits.

4. classification of governors
• the governors are mainly divided in to two types
these are further in to following types according to design.

5. governor characteristics
• the main characteristics of a governing system is there fore the
reletionship between the generated load of the controlled machine
and speed,which is the prime governor input .
• different governors can be compared on the basis of following
characteristics
• stability a governor is said to be stable when there is one radius of
rotation of the balls for each speed which is within the speed range
of the governor.
• sensitiveness it is define as the extent of sleave movement for a
change in speed of the governor.
• as agovernor is used to limit the change of speed of the engine
between a minimum to full load conditions the sensitiveness is also
defined as the ratio of the range of speed to the mean equilibrium
speed.
sensitiveness =N2-N1/N=2(N2-N1)/(N2+N1)
where N2-N1 = speed range from no load to full load.

6. cont...
• controlling force is when governor running each ball of the governor
subjected an inward pull.
• consider a governor running at a steady speed, then the inward force
acting on the rotating governor ball is known as controlling force.
• controlling force of governor is equal and opposite to the centrifugal
reaction.

7. cont...
• isochronism a governor is said to be isochronous if equilibrum speed is
constant for all the radii of rotation in the working range.
• therefore, fore an isochronous governor the speed range is zero and this types
of governor shall maintain constant speed.
• hunting an excessivelyfast too and fro motion of the sleeve between the
stopper due to resonance condition is knoun as hunting of governor.
• higher the sensitiveness of the governor,the problem of hunting becomes more
acute.
stability =1/sensitivity

8. PORTER GOVERNOR
- is adead weight loaded type governor works on the action of gravity.
-it is a modification of watt governor,with centeral load attached to the sleeves.
 in porter governor two balls are located at the top and load is attached to the sleeves.
 the lower link is connected to central sleeve and two stoppers are proided to control the movements of
sleeves.
 a mechanism is attached to the sleeves to operates the throttle value.
 the balls tend two moves up and down on the spidle due to the speed of revolution of the spindle.as load
at the engine decreases speed of the engine as well as spindle also tends to increases.

9. hartnell governor
consists two bell cranks situated the different points of
the frame.
 a frame is attached to the spindle each lever carries a ball to the horizontal
roller at the end of vertical arm.
 the helical ring is provided to maintain the equal level force on the rollers
and arrangement of the screw is there to adjust a force of the spring.
 is a spring controlled
centrifugal governor,

10. centrifugal shaft governor
 it consists of two ball of equal the centrifugal governors are based on the
balancing of centrifugal force on the rotating balls by an equal and opposite
radial force ,known as the controlling force.
 it consist of two balls of equal mass ,which are attached to the arms as
shown in figure these ball are known as gevernor balls or fly balls.
 the balls revolve with as piddle which is driven by the engine through bevel
gears.
types centrifugal governors
• pendulum type governor
watt governor
• loaded type governor
dead weight governor
porter governors
poll governors
spring loaded governors
hartnell governors
hartung governors
wilson-hartnell governors and pickering governors

11. centrifugal governor working
• the main working principle behind these types of governor is the balancing of the
centrifugal force.
• these balls will be revolving around the spindle which is driven by the engine.
• A ball crank lever is connected to the sleeve and the other end of it also will be
connected to throttle valve located in the fuel supply passege .

12. inertia governors
is the balls in inertia governor are arranged in such a
way that the inertia forces caused by angular acceleration or
retardation of the governor shaft tend to change their position.
 is more sensitive than centrifugal governor but in this governor,it is
very difficult to completly balance the revolving part.
 inertia governor are less frequently used than centrifugal governors.
 the function of a governor is to regulate the mean speed of an engine.
 a speed control device utilizing suspended masses that respond to
speed changes by reason of their inertia.

13. con’t...
• when the disc of the inertia governor rotates and when the speed of disc is
increased or when the rotation of disc is accelerated, the balls moves in the
opposite direction to the rotation of the disc.
• the movement of this ball in opposite direction is controlled by the spring available
in the governor.
• advantages
-highly sensitive to increase or decrease in load.
-quick response to change in load
• disadvantages
-difficult to completly balance the revolving parts.

14. difference between centrifugal and inertia governor