Applications of Hydraulics&Pneumatics : Session 9

8/3/2019 Applications of Hydraulics&Pneumatics : Session 9

1/14

1

Electro -

HydraulicsPneumatics

&

By: Alireza Safikhani

9

2

Electro Hydraulic Press

The hydraulic press is controlledThe hydraulic press is controlledvia the electrical control panel.via the electrical control panel.

Electrical signals are used toElectrical signals are used to

activate the valves in theactivate the valves in the

hydraulic installation.hydraulic installation.

The electro hydraulic press is usedThe electro hydraulic press is used

to form rectangular troughs.to form rectangular troughs.

3

Electro Hydraulics4

Comparison


2/14

5 Electro Hydraulics Hydraulic systems are used w herever high pow erHydraulic systems are used w herever high pow er

concentration, good heat dissipation or extremelyconcentration, good heat dissipation or extremely

high forces are required.high forces are required.

ElectroElectro--hydraulichydraulic systems are made up of hydraulicsystems are made up of hydraulic

and electrical components:and electrical components:

The movements and forces are generated byThe movements and forces are generated by

hydraulic means (e.g. by cylinders).hydraulic m eans (e.g. by cylinders).

Signal input and signal processing, on the otherSignal input and signal processing, on the other

hand, are effected by electrical and electronichand, are effected by electrical and electronic

components (e.g. electromechanical sw itchingcomponent s (e.g. electromechanical sw itchingelements or storedelements or stored--program controls).program controls).

6 Sections of an Electro hydraulic System

7 Sections of an Electro hydraulic System Signal control sectionSignal control section

Inpu t and processing of electrical signals.Inpu t and processing of electrical signals.

Solenoid valves form the interface between theSolenoid valves form the interface between the

electrical signal control section and the hydraulicelectrical signal control section and the hydraulic

power section.power section.

Hydraulic power sectionHydraulic power section

Controls the flow of hydraulic fluid by means ofControls the flow of hydraulic fluid by means of

solenoid valves. Actuators convert hydraulic energysolenoid valves. Actuators convert hydraulic energy

into motions.into motions.

8 Electro Hydraulics


3/14

9

Electrical power supply unit

Connection to m ains supply.

Supplies signal control section w ith specified ormaximum voltage and current values includes.

Voltage transformation

Rectification

Stabilization

Fuse protection

In mobile hydraulic systems, rechargeable battery

systems or generators are used as a power supply forthe signal control section.

10

Analogue, digital and binary

11

Electrical power supply unit12

Components Of EH Circuits

StandardsStandards

ANSIANSI

DIN (40 900)DIN (40 900)

ISOISO


4/14

13

Switching Contacts and Types of Actuation

The follow ing sw itch contact designs are used as inputThe follow ing sw itch contact designs are used as input

and processing elements:and processing elements:

NormallyNormally --open contactopen contact NormallyNormally --closed contactclosed contact

Changeover contactChangeover contact

Types of actuation for switching elements are:Types of actuation for swit ching elements are:

ManualManual

Mechanical

RelayRelay Magnet fieldMagnet field

Ident ifying letters in electrical circuit diagr ams: S (S1, S2, .Iden tifying letter s in electrical circuit diagrams: S (S1, S2, ...)..)

14

Switching Elements

15 Momentary and sustained contact switches A mom entary contact switch has aA mom entary contact switch has a rest positionrest positionand anand an

actuated positionactuated position..

A sustained contact switch has tw o detents. It thus has tw o restA sustained contact switch has tw o detents. It thus has tw o restpositions.positions.

Momentary and sustained switches can close or open currentMomentary and sustained switches can close or open currentpaths or switch from one current path to another.paths or switch from one current path to another.

16 N/O, N/C and changeover contacts N/ O: Contact normally open in rest position.N/ O: Contact normally open in rest position.

N/ C: Example, MomentaryN/ C: Example, Momentary--contact switchcontact switch

Changeover contact: N/O and N / C contacts in a single housing;Changeover contact: N/O and N / C contacts in a single housing;

one contact is open while the other is closed.one contact is open while the other is closed.


5/14

17

Limit Switches

Determining the position of a positioning sl ide.Determ ining the position of a positioning slide.

Electrical contacts are actuated when a defined intermediate orElectrical contacts are actuated when a defined intermediate or

end position is reachedend position is reached. Limit switches can be connected up as N/ O, N/ C or changeoverLimit switches can be connected up as N/ O, N/ C or changeover

contacts.contacts.

18

Rotary & Latch Switches

19

Proximity switches

InductiveInductive

Signal is generated by the presence of any material w ith goodSignal is generated by the presence of any material w ith good

conductivity in an osci l lating magnetic field.conductivity in an osci l lating magnetic field.

CapacitiveCapacitive Signal is also generated by al l insulators with high dielectricSignal is also generated by al l insulators with high dielectric

constants in an electrical field.constants in an electrical field.

OpticalOptical

Signal is generated when l ight barriers are interrupted orSignal is generated when l ight barriers are interrupted or

when l ight is reflected back to an optical sensor.when l ight is reflected back to an optical sensor.

ReedReed switchesswitches

Signal is generated by magnets w hose fields close the builtSignal is generated by magnets w hose fields close the built -- inin

contacts in the switch.contacts in the switch.

20

Proximity switches


6/14


7/14

25

Pressure switches26 Solenoid (electromagnet)

A coil carrying an electrical current develops a un iformA coil carrying an electrical current develops a un iform

magnetic field in its ax ial direction due to themagnetic field in its axial direction due to the

overlapping of field lines.overlapping of field lines. By appropriate alignment of elementary magnets, anBy appropriate alignment of elementary magnets, an

iron core can be made into a switchab leiron core can be made into a sw itchable

electromagnet.electromagnet.

27

Relay

the construction of a relay can be very differen t, but the functthe construction of a relay can be very different, but the functionionis nevertheless the same in principle:is nevertheless the same in principle:

When a voltage is applied to the relay coil through contactsWhen a voltage is applied to the relay coil through contactsA1 and A2, an electric current flow s through the w indings. AA1 and A2, an electric current flow s through the w indings. A

magnetic field is built up and pulls the armature against themagnetic field is built up and pulls the armature against thecore of the coil.core of the coil.

Switch contact 1 is connected with switch contact 4.Switch contact 1 is connected with switch contact 4.

After removing the v oltage, the armature is brought back intoAfter removing the voltage, the armature is brought back intoits initial position by a spring.its initial position by a spring.

Switching contact 1 is connected w ith switching contact 2.Switching contact 1 is connected with switching contact 2.

A relay can have m ultiple switching contacts which can beA relay can have m ultiple switching contacts which can beactuated simultaneously.actuated simultaneously.

There are the fol lowing ty pes, for exam ple:There are the fol lowing types, for example:

Polarized relayPolarized relay Current impulse relayCurrent impulse relay

Time relayTime relay

Thermal relayThermal relay

28

Relay

Iden tifying letter s in electrical circuit diagrams: Y (Y1, Y2, .Ident ifying letters in electrical circuit diagr ams: Y (Y1, Y2, ...)..)

Identifying letters for RELAYS in electrical circuit diagrams:Identifying letters for RELAYS in electrical circuit diagrams: K (K 1, K2, ...)K (K 1, K2, ...)


8/14

29

Representation in Circuits30

Electrical Output Devices

Supply acoustic signals:Supply acoustic signals:

For example, horns, sirensFor example, horns, sirens

Ident ifying letters in electrical circuit diagram s: H (H1, H2,Ident ifying letters in electrical circuit diagram s: H (H1, H2, ...)...)

Supply optical signals:Supply optical signals:

For example, lamps,For example, lamps, LEDsLEDs

Ident ifying letters in electrical circuit diagram s: H (H1, H2,Ident ifying letters in electrical circuit diagram s: H (H1, H2, ...)...)

Do work:Do work:

For example, electric motorsFor example, electric motors Identifying letters in electrical circuit diagrams: M (M1, M2 ,Identifying letters in electrical circuit diagrams: M (M1, M2 , ...)...)

31

Electrical Output Devices32

Electrical Circuit Symbols, General


9/14

33

Switching elements34

Electromechanical switching elements

35

Block symbols for proximity sensors36

Direct activation indirect activation

Direct activationDirect activation

Connection of a solenoid valve via a switch

Indirect activationIndirect activation

Connection of a solenoid valve via a relay Advantage of indirect activationAdvantage of indirect activation

Separation of control and pow er circuits

The current passing through sw itch S1 (Fig. B) is low er, andthe service life of the sw itch is significantly greater.


10/14

37

Signal inversion

The output signal is inversely proportional to the input signal.

38

Animation

39

Latching

Latching only with indirect activation.Latching only with indirect activation.

Actuation of switch S1: Relay K1 reverses holding the currentActuation of switch S1: Relay K1 reverses holding the current

path of K1 closed.path of K1 closed.

The actuation of switch S2 interrupts the latched current path.The actuation of sw itch S2 interrupts the latched current path.

40

Circuit diagram

In the P neumatic/ Hydraulic circuit diagram, the signal flow isIn the P neumatic/ Hydraulic circuit diagram, the signal flow is

represented from bottom to top.represented from bottom to top.

In the electrical circuit diagram, the signal flow is representIn the electrical circuit diagram , the signal flow is represent ed fromed from

top to bottom.top to bottom.

Lines of potential with constant voltage are draw n horizontal ly.Lines of potential with constant voltage are draw n horizontal ly.

Current paths are draw n vertical ly and numbered consecutively.Current paths are draw n vertical ly and numbered consecutively.

Circuit symbols are show n in the direction of current flow.Circuit symbols are show n in the direction of current flow.

Switching elements are generally shown under zeroSwitching elements are generally shown under zero --voltagevoltage

conditions.conditions.


11/14

41

Example42

Example Animation

43

The AND Logic Function44 The OR Logic Function


12/14

45

Direct Actuation of a Single-Acting Cylinder46 Indirect Actuation of a Double-Acting Cylinder

47

Cylinder Actuation48

ANSI


13/14

49

ANSI 150

ANSI 2

51

ANSI 352

ANSI 4


14/14

53

ANSI of Slide 4654

ANSI 6

Applications of Hydraulics&Pneumatics : Session 9

Documents

Transcript of Applications of Hydraulics&Pneumatics : Session 9