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SIX MONTHS INDUSTRIAL TRAINING AT HAVELLSINDIA LTD.

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COMPANY PROFILEHavells India Limited is one of the largest electrical and

power distribution equipment Company in the country,manufacturing products as under:

Industrial and domestic switchgear Power cables Energy meters Fans Luminaries

Bath fitting Modular switches. It is countrys largest manufacturer of miniature circuit

breaker and is among the top ten internationalmanufacturers.

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GENERAL LAYOUT OF HAVELLS INDIA

LIMITED BADDI (H.P)

The plant has the following three manufacturing divisions:

Domestic unit

Export Oriented Unit (EOU)

Industrial Products/ Crabtree ( Switches, fuse,

changeover, etc)

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STUDY OF MCBMiniature Circuit Breaker - electromagnetic device

used to feed electricity to houses, industries, railways,etc.

Provides protection against short circuit and overloadconditions.

Switching Mechanism

Contact MechanismArc Extinguishing device

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WORKING PRIN

CIPLE OF SOLENOID TOPROVIDE PROTECTION FROM SHORT

CIRCUITFaradays law - when current is passed through asolenoid (coil shaped thing) f lux is produced aroundthe coil, due to this the medium inside the coilbecomes magnetized & there is a force of attractionbetween the 2 parts (Anchor assembly & coil rivet)

only if it is a magnetic material.By this the plunger trips the mechanism.

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WORKING PRINCIPLE OF BIMETAL FOR

PROTECTION FROM OVERLOAD

Cantilevers principle - The different elements havedifferent thermal expansions. When 2 differentelements were bonded together physically withdifferent thermal expansions & exposed to hightemperatures it turns into curvature.

When we fix one end of the bimetalthen all the deflection happens at the free end, this iscalled cantilever principle.

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MAIN COMPONENTS USED

Bimetal

Pointer

Bimetal carrier

Anchor spring

Plastic latch

Anchor assemblyAluminium bush

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uCONTINUEDCoil rivet

Coil washer

Arc runnerOuter yoke

Latching fork & u latch

Operating fork

D.T. Spring & s.T. Spring

Knob & knob link

M.S. Pin

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INTERNAL VIEWOF MCB

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VARIOUS STAGES TO MANUFACTURE AMCB

Spot welding

Mechanism assemblyCalibration and testing

Verification

Packaging

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TESTING AND VERIFICATION

In this unit MCBs are tested whether they are tripping withinthe required time limit or not. This process comprises offour cycles:

At T1 Current passesAt T2- Screw sets

At T3- Angle sets (Angle is determined between bimetaland carrier)

At T4- Tripping occursThere are various types of indicators:

Red- If theres no fault

Yellow- If fault occurs

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STUDY OF RCCB (RESIDUALCURRENT

CIRCUIT BREAKER)Residual current circuit breaker - also called ELCB (earth leakage

circuit breaker) or RCD (residual circuit device)Function

Breaks the circuit automatically when it senses fraction of anampere leakage current flowing to earth in excess topredetermined amount.

RCCB provides high degree of effective protection againstelectric shock or death due to direct or indirect contact to livepart by human being.

Prevents fire hazards by sensing less than 1 amp leakage currentflowing to earth. Stops the unused leakage current flow as low as 30 mA and saves

electric charges.

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PRINCIPLE INVOLVED IN RCCB TRIPPING

Current balance principle- Kirchoffs Current Law

In a healthy circuit the current in phase is equal to

current in neutral and vector sum of the current iszero.

During earth leakage the vector sum of current is notzero. This imbalance induces a current on the

secondary winding of the current transformer, whichin turn trips the RCCB mechanism.

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STUDY OF RCBO

Residual Current Circuit Breaker with overloadand short circuit conditions - single composite

device which provides protection against over currentsand earth leakage faults in the same width and profileas that of a standard MCB.

RANGE

6A, 10A, 16A, 20A, 25A, 32A & 40ASENSITIVITY

30mA, 100mA, 300mA

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WORK TO BE DONE

Manufacturing of ACCL(Automatic Changeover

Current Limiter)

Work to be done in Export unit

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THANK YOU