Phase 1 Project Presentation of 3 pahase induction motor

7/28/2019 Phase 1 Project Presentation of 3 pahase induction motor

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Project Supervisor:

Madam Nida Kashif

Group Members:

Khurum Sharif

Ata-ur-Rehman Khalid

Nadeem Asghar

Controlling, Monitoring and Faults detection

of Industrial Motor using PLC


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Block Diagram


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Induction Motor

An induction motor or asynchronous motor isa type of alternating current motor where

power is supplied to the rotor by means of

electromagnetic induction.


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Types of Induction Motor

Two types of induction motor which arecommonly used

1. Single phase induction motor

2. Three phase induction motor


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Three Phase Induction Motor A 3-phase induction motor has a stator and a rotor.

The stator carries a 3-phase winding (called stator winding) while

the rotor carries a short-circuited winding (called rotor winding).

Only the stator winding is fed from 3-phase supply.

The rotor winding derives its voltage and power from theexternally energized stator winding through electromagnetic

induction and hence the name.

The induction motor may be considered to be a transformer with

a rotating secondary and it can, therefore, be described as a

transformer type AC machine in which electrical energy isconverted into mechanical energy.


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Equivalent Circuit of 3-Phase Induction Motor at

Any Slip

Fig. shows the equivalent circuit (though not the only one)

per phase for an induction motor.


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V1 = applied voltage per phase to the stator

R1= stator resistance

X1=stator leakage reactance per phase

E1= self induced e.m.f in the stator winding

E'2 =mutually induced e.m.f (E'2= s E2 = s K E1 where K

transformation ratio) is induced in the rotor winding.

The flow of stator current I1 causes voltage drops in R1and X1.V1 = -E1 + I1(R1 + j X1) ...phasor sum

R2= rotor resistance

X2= rotor leakage reactance per phase

The induced voltage/phase in the rotor is E'2 = s E2 = s K E1.

Since the rotor winding is short-circuited, the whole of e.m.f E'2

is used up in circulating the rotor current I'2.

E'2 = I'2 (R2 + j s X2 )

The rotor current I'2 is reflected as I"2 (= K I'2) in the stator. The

phasor sum of I"2 and I0 gives the stator current I1.


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Circuit breaker:

A circuit breakeris an automaticallyoperated designed to protect an electrical

circuit from damage caused by overload or short

circuit.

Its basic function is to detect a fault condition and

interrupt current flow.

Unlike a fuse, which operates once and then

must be replaced, a circuit breaker can be reset

(either manually or automatically) to resume

normal operation.


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There are different types of circuit breaker

including bimetallic, thermal magnetic andmagnetic circuit breakers.

A typical three phase circuit breaker is given

below


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Contactors:

Contactors typically have multiple contacts, andthose contacts are usually (but not always)

normally-open, so that power to the load is shut

off when the coil is de-energized

Most common industrial use for contactors is the

control of electric motors.


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Working of contactors:

Typical contactor working diagra is given below

The top three contacts switch the respective

phases of the incoming 3-phase AC power,

typically at least 480 Volts for motors 1

horsepower or greater.


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The lowest contact is an "auxiliary" contact which has

a current rating much lower than that of the large

motor power contacts, but is actuated by the same

armature as the power contacts . The auxiliary contact is often used in a relay logic

circuit, or for some other part of the motor control

scheme, typically switching 120 Volt AC power

instead of the motor voltage. One contactor may have several auxiliary contacts,

either normally-open or normally-closed, if required.


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Phase failure relay A phase failure relay monitors the incoming three

phase service lines.

If the lines become reversed or loss of one phase

causing single phasing, the relay's internal contacts

change status. In control panels the control voltage usually is

connected through the phase failure relay's auxiliary

contacts.

If any line anomalies occur the control voltage is cutoff and the panel becomes inoperable.

Once the line fault is corrected the fault relay senses

that everything is alright and then allows the control

voltage to power the control panel again.


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Thermal overload relay:

It operates whencurrent increases from

certain specific limits.

It normal close

contacts closes when

current increases from

certain limits


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There are different types of phase failure relay,

zahra RST-25 is such type of relay which can

sense phase failure, phase sequence and over ,under voltage.


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Current sensor:

The device consists of a precise, low-offset, linearHall circuit with a copper conduction path located

near the surface of the die.

Applied current flowing through this copper

conduction path generates a magnetic field which

the Hall IC converts into a proportional voltage.


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The output of the

device has a positive

slope when anincreasing current

flows through the

primary copper

conduction path (frompins 1 and 2, to pins 3

and 4), which is the

path used for current

sampling.


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Proximity sensor:

Inductive Proximity Sensors detect the presence of metal

objects which come within range of their oscillating field

and provide target detection to zero speed.

Internally, an oscillator creates a high frequencyelectromagnetic field (RF) which is radiated from the coil

and out from the sensor face . When a metal object enters

this field, eddy currents are induced into the object.


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As the metal moves closer to the sensor, these

eddy currents increase and result in an

absorption of energy from the coil which dampens

the oscillator amplitude until it finally stops.


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Potential Transformer

Transformer:

A transformer is a device that transfers electrical

energy from one circuit to another through

inductively coupled conductorsthe transformer's

coils.


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Programmable Logic Controllers

A programmable logic controller (PLC) is aspecialized computer used to control

machines and process.

It uses a programmable memory to storeinstructions and execute specific functions

that include On/Off control, timing, counting,

sequencing, arithmetic, and data handling.


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Relays:

Relays:

A relay is an electrically

operated switch.

Current flowing through thecoil of the relay creates a

magnetic field which

attracts a lever and

changes the switchcontacts.

The coil current can be on

or off so relays have two

switch positions and most


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PLC programming


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LADDER DIAGRAM:


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SCADA

The term SCADA usually refers to centralizedsystems which monitor and control entire sites, or

complexes of systems spread out over large

areas (anything from an industrial plant to a

nation). Most control actions are performed automatically

by PLCs.

Host control functions are usually restricted to

basic overriding orsupervisorylevel intervention.


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SCADA DEVELOPEMENT


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Phase 1 Project Presentation of 3 pahase induction motor

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