1. Actuators
Presented by:-
Er. Sanyam S. Saini
ME (I&CE) (Regular)
2012-14

2. Outlines
 Introduction to Actuators.
 Classification of Actuators
 Pneumatic Actuators & Classifications-
(i). Introduction; (iv). Working ;
(ii). working Principle; (v). Advantages & Disadvantages;
(iii). Construction; (vi). Applications
 Hydraulic actuators & Classifications- -
(i). Introduction; (iv). Working ;
(ii). working Principle; (v). Advantages & Disadvantages;
(iii). Construction; (vi). Applications
 Electrical Actuators & Classifications- -
(i). Introduction; (iv). Working ;
(ii). working Principle; (v). Advantages & Disadvantages;
(iii). Construction; (vi). Applications
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3. Introduction to Actuators.
 An actuator is something that actuates or moves something.
 An actuator is a device that coverts an input energy into
motion or mechanical energy.
 The input energy of actuators can be “manual” (e.g., levers
and jacks), hydraulic or pneumatic (e.g., pistons and valves),
thermal (e.g., bimetallic switches or levers), and electric (e.g.,
motors and resonators).
 Actuators are final element in a control system.
 The actuator was discovered by Logan in 1969.
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4. Introduction to Actuators
 An actuator is that creates motion in a straight line, as
contrasted with circular motion of a conventional electric
motor.
 Linear actuators are used in machine tools and industrial
machinery, in computer peripherals such as disk drives and
printers, in valves and dampers, and in many other places
where linear motion is required.
 Hydraulic or pneumatic cylinders inherently produce linear
motion; many other mechanisms are used to provide a linear
motion from a rotating motor
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5. Classification of Actuators
 Pneumatic
 Hydraulic
 Electrical/Electronic
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6. Pneumatic Actuators
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7. Pneumatic Actuators
 A set of devices into with one or more pneumoengines, which
are determined to start mechanisms or some other objects by
means of pressed working gas is called pneumatic actuator, or
pneumoactuator.
 The devices intended for transformation of potential and kinetic
energy of the stream of compressed gas in mechanical energy
of the output link that can be, for example, a rod of the piston, a
shaft of the turbine or the case of the jet device is called
pneumatic engines of the automated actuator.
 They are devices providing power and motion to automated
systems, machines and processes.
 A pneumatic cylinder is a simple, low cost, easy to install device
that is ideal for producing powerful linear movement.
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8. Basic Construction
1
1 cushion seal 2
2 magnet 14 3
4
3 cushion sleeve 5
4 barrel 6
5 guide bush
6 rod and wiper seal
7 front end cover
8 front port
9 reed switch
10 piston rod 13
11 wear ring 12
12 piston seal 11
13 rear end cover 10
14 cushion screw 9
8
7
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9. Types of Pneumatic Actuator
 Pneumatic actuators are made in a wide variety of sizes, styles and
types including the following
 Single acting with and without spring return
 Double acting
 Rod less
 Rotary
 Clamping
 Bellows
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10. Single acting spring return
 Single acting cylinders have a power stroke in one direction only
 Normally in
 Normally out
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11. Double acting
 Double acting cylinders use compressed air to power both the
outstroke and instroke.
 Superior speed control is possible
 Non cushioned cylinders are suitable for full stroke working at
slow speed.
 Higher speeds with external cushions.
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12. Advantages of Pneumatic
Actuators.
 Simplicity of realization relatively to small back and forth
motions;
 Sophisticated transfer mechanisms are not required;
 Low cost;
 High speed of moving;
 Ease at reversion movements;
 Tolerance to overloads, up to a full stop;
 High reliability of work;
 Explosion and fire safety;
 Ecological purity;
 Ability to accumulation and transportation.
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13. Disadvantages of Pneumatic
Actuators.
 Compressibility of the air ;
 Impossibility to receive uniform and constant speed of the
working bodies movement ;
 Difficulties in performance at slow speed;
 Limited conditions - use of compressed air is beneficial up to
the definite values of pressure;
 Compressed air requires good preparation
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14. Hydraulic Actuator
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15. Introduction
 A hydraulic drive system is a drive or transmission system that
uses pressurized hydraulic fluid to drive hydraulic machinery.
 The term "hydraulic actuator" refers to a device controlled by a
hydraulic pump.
 A familiar example of a manually operated hydraulic actuator is a
hydraulic car jack. Typically though, Principle Used in Hydraulic
Actuator System
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16. Working Principle of Hydraulic
Actuator
Pascal’s Law
 Pressure applied to a confined fluid at any point is transmitted undiminished
and equally throughout the fluid in all directions and acts upon every part of
the confining vessel at right angles to its interior surfaces.
Amplification of Force
 Since pressure P applied on an area A gives rise to a force F, given as,
F=P A
Thus, if a force is applied over a small area to cause a pressure P in a
confined fluid, the force generated on a larger area can be made many times
larger than the applied force that crated the pressure.
 This principle is used in various hydraulic devices to such hydraulic press to
generate very high forces.
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17. Construction of Hydraulic Actuator
 A hydraulic drive system consists of three parts:
1.Generator (e.g. a hydraulic pump), driven by an electric motor,
2. Combustion engine or a windmill; valves, filters, piping etc.
(to guide and control the system)
3. Motor (e.g. a hydraulic motor or hydraulic cylinder) to drive the
machinery.
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18. Hydraulic Actuator
 Parts of a typical cylinder
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19. Working of Hydraulic
Actuators
 Hydraulic actuators or hydraulic cylinders typically involve a
hollow cylinder having a piston inserted in it. An unbalanced
pressure applied to the piston provides force that can move an
external object. Since liquids are nearly incompressible, a
hydraulic cylinder can provide controlled precise linear
displacement of the piston. The displacement is only along the
axis of the piston.
 The piston forms sealed, variable-volume chambers in the
cylinder
 System fluid forced into the chambers drives the piston and
rod assembly
 Linear movement is produced
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20. Classifications of Hydraulic
Actuator
 Cylinders are typically classified by operating principle or by
construction type
– Single-acting or double-acting
– Tie rod, mill, threaded end, or one piece
 Single-acting cylinders exert force either on extension or
retraction.
 They require an outside force to complete the second motion
 Double-acting cylinders generate force during both
extension and retraction
– Directional control valve alternately directs fluid to opposite
sides of the piston
– Force output varies between extension and retraction
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21. Hydraulic Actuator
 Single- and Double-Acting Cylinders
Single-acting Double-acting
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22. Hydraulic Actuator
 Tie-Rod Cylinder
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23. Hydraulic Actuator
 Mill cylinders
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24. Hydraulic Actuator
 Threaded-end cylinder
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25. Advantages of Hydraulic
Actuators
 Infinitely variable control of gear-ratio in a wide range and an
opportunity to create the big reduction ratio;
 Small specific weight, i.e. the weight of a hydro actuator is in
ratio to transmitted capacity (2-3 kg / kWt);
 Opportunity of simple and reliable protection of the engine from
overloads;
 Small sluggishness of the rotating parts, providing fast change
of operating modes (startup, dispersal, a reverser, a stop);
 Simplicity of transformation of rotary movement into
reciprocating one;
 Opportunity of positioning a hydraulic engine on removal
(distance) from an energy source and freedom in making
configuration.
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26. Disadvantages of Hydraulic
Actuators
 Efficiency of a volumetric hydraulic actuator is a little bit
lower, than efficiency of mechanical and electric transfers,
and during regulation it is reduced;
 Conditions of operation of a hydraulic actuator (temperature)
influence its characteristics;
 Efficiency of a hydraulic actuator is a little reduced in the
process of exhaustion of its resource owing to the increase in
backlashes and the increase of outflow of liquid (falling of
volumetric efficiency);
 Sensitivity to pollution of working liquid and necessity of high
culture service.
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27. Applications of Hydraulic
Actuators
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28. Electrical Actuators
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29. Introduction
 An electrical motor is an Transducer & an Actuator because it
converts electrical current into a large magnetic field which then
turns a shaft. (Mechanical energy)
 All electric motors use electromagnetic induction to generate a
force on a rotational element called the rotor.
 The torque required to rotate the rotor is created due to the
interaction of magnetic fields generated by the rotor, and the
part surrounding it, which is fixed, and called the stator.
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30. Classification of Electrical
Actuators
 Solenoid
 Electrical Motors
 Stepping Motors
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31. Solenoid
 Simple form of electromagnet that
consists of a wire bobbin of isolated
copper, or of another appropiate
conductor, who is coiled in spiral
around the surface of a cylindrical
body, generally with transverse
circular section.
 When the electrical current is sent
across these wound, they act as
electromagnet.
 The created magnetic field is the
motive force used to open the valve.
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32. Electric Motors
 Electromechanical device that converts electrical energy to
mechanical energy
 The physical principle of all electric motors is that when an
electric current is passed through a conductor (usually a coil of
wire) placed within a magnetic field, a force is exerted on the wire
causing it to move.
 Mechanical energy used to e.g.
 Rotate pump impeller, fan, blower
 Drive compressors
 Lift materials
 Motors in industry: 70% of electrical load
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33. Electric Motors
Electric Motors
Alternating Current Direct Current (DC)
(AC) Motors Motors
Synchronous Induction
Separately Self Excited
Excited
Single-Phase Three-Phase Series Compound Shunt
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34. Applications
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35. Thank You
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