StandardsStandards• IS 13947

• IEC 60947

• Below or Equal to

1000V for AC

&

1200V for DC

LOW VOLTAGE

SWITCHGEARSWITCHGEAR SWITCHINGSWITCHING PROTECTION

CONTACTOR

RELAYSTARTER

HRC FUSE

ACBMCCBMPCB

SWITCH / SD

SFU/FSU/SDF

Y

Y

NY

YNYY

Y

N

YY

NY

YY

Y

Y

CONTACTOR As per IS 13947 CONTACTOR As per IS 13947 PART 4PART 4

A mechanical switching device having only one position of rest operated otherwise than by hand, capable of making, carrying and breaking currents under normal circuit condition including operating overload condition.

CONTACTORCONTACTOR A SIMPLE ELECTROMAGNETIC SWITCHA SIMPLE ELECTROMAGNETIC SWITCH

FORFOR

FREQUENT OPERATIONFREQUENT OPERATION

WITHWITH

NO - VOLT PROTECTIONNO - VOLT PROTECTION

Core competencyCore competency

High Operational Life

CONTACTOR CONTACTOR MAIN APPLICATION AREAS

SWITCHING OF MOTORS SWITCHING OF LIGHTING LOADS SWITCHING OF HEATING LOADS SWITCHING OF CAPACITORS SWITCHING OF DC LOADS

SYMBOLS FOR CONTACTOR SYMBOLS FOR CONTACTOR MAIN CIRCUITMAIN CIRCUIT

2/T14/T26/T3

1/L13/L25/L3

SYMBOLS FOR CONTACTOR SYMBOLS FOR CONTACTOR AUXILIARY CIRCUITAUXILIARY CIRCUIT

A1 A2

13

21 22

14

LIMITS OF OPERATIONLIMITS OF OPERATION

Pick Up – 85% to 110% of UcDrop Off – 75% to 20% of Uc ( for

a.c.) 75% to 10% of Uc (for

d.c.)

Where Range is specified75% & 85% shall apply to Lower Value

110%, 20% & 10% shall apply to Higher Value

WHY CONTACTOR ?WHY CONTACTOR ?

HIGH OPERATIONAL LIFE HIGH FREQUENCY OF OPERATION CAN BE OPERATED FROM REMOTE CAN BE USED FOR AUTOMATIC

SWITCHING OPERATIONS CAN OFFER NO VOLT

PROTECTION

SELECTION OF SELECTION OF CONTACTORCONTACTOR

PARAMETERSPARAMETERS RATED OPERATIONAL VOLTAGE, Ue

RATED OPERATIONAL CURRENT, Ie FREE AIR OR ENCLOSED THERMAL

CURRENT, Ith & Ithe UTILIZATION CATEGORY ELECTRICAL & MECHANICAL LIFE

PARAMETERSPARAMETERS

RATED CONDITIONAL S/C CURRENT FREQUENCY OF OPERATION COIL VOLTAGES NUMBER OF AUXILIARY CONTACTS DIMENSIONS TERMINAL SIZE EASE OF MAINTENENCE AVAILABILITY OF SPARES

SELECTION OF SELECTION OF CONTACTORCONTACTOR

AC 1AC 1

AC 2AC 2

NON-INDUCTIVE / SLIGHTLY INDUCTIVE LOADS,RESISTANCE FURNACES

SLIP RING MOTORS: STARTING , SWITCHING OFF

AC 3AC 3 SQUIRREL CAGE MOTORS : STARTING,SWITCHING OFF DURING RUNNING

AC 4AC 4 SQUIRREL CAGE MOTORS : STARTING,PLUGGING & INCHING

UTILISATION CATEGORIESUTILISATION CATEGORIES

SELECTION OF SELECTION OF CONTACTORCONTACTOR

SELECTION PARAMETERSSELECTION PARAMETERS

UTILISATION CATEGORIESUTILISATION CATEGORIES

AC 5aAC 5a SWITCHING OF ELECTRIC DISCHARGE LAMP CONTROLS

AC 5bAC 5b SWITCHING OF INCANDESCENT LAMPS

SWITCHING OF TRANSFORMERS

SWITCHING OF CAPACITOR BANKS

AC 6aAC 6a

AC 6bAC 6b

( MAKING & BREAKING CONDITIONS ACCORDING TO UTILISATION CATEGORY )

Utilization Cat.

Make Break

I / Ie U / Ue COS Ic / Ie Ur / Ue COS

AC 1 1 1 0.95 1 1 0.95

AC 2 2.5 1 0.65 2.5 1 0.65

AC 3 6 1 0.35 1 0.17 0.35

AC 4 6 1 O.35 6 1 O.35

VERIFICATION OF NUMBER OF ON LOAD OPERATINAL PERFORMANCE

SELECTION PARAMETERS SELECTION PARAMETERS

A TYPICAL ELECTRICAL LIFE CURVE A TYPICAL ELECTRICAL LIFE CURVE FORFOR UTILISATION CATEGORY AC4UTILISATION CATEGORY AC4

OPERATING CURRENT IN AMPERES

NO

. OF

OP

ER

AT

ING

CY

CL

ES

ELECTRICAL DURABILITYELECTRICAL DURABILITY

SELECTION PARAMETERS SELECTION PARAMETERS ELECTRICAL LIFE IN MIXED ELECTRICAL LIFE IN MIXED

DUTY APPLICATIONDUTY APPLICATION

WHERE, N = ELECTRICAL LIFE IN MIXED DUTY

A = ELECTRICAL LIFE IN AC 3 DUTY

B = ELECTRICAL LIFE IN AC4 DUTY

C = PERCENTAGE OF AC 4 OPERATION OF TOTAL OPERATION

N = A

1 +C

100

A

B 1

RELAYRELAY

• A device designed to produce sudden predetermined changes in one or more electrical output circuit when certain condition are fulfilled in electrical input circuit controlling the device.

BIMETAL OVERLOAD RELAYBIMETAL OVERLOAD RELAY

ADVANTAGES :

1. THERMAL MEMORY

2. ACCURATE PROTECTION

3. ADJUSTIBILITY

4. AMBIENT COMPENSATION

5. COMPACT CONSTRUCTION

6. LONG LIFE

7. ECONOMICAL

BIMETAL

UPPER SLIDE

LEVER

STOPPER

LOWER SLIDE

BIMETALLIC OVERLOAD RELAYBIMETALLIC OVERLOAD RELAYWITH DOUBLE SLIDE MECHANISMWITH DOUBLE SLIDE MECHANISM

Multiple of Set Current

Trip Classes for All Relay

(Tripping Time)

1.05 ≥ 2 hours

1.2 ≤ 2 hours

  10A 10 20 30

1.5 < 2min. < 4min < 8min < 12min

7.2 2-10sec 4-10sec 6-20sec 9-30sec

As per IS : 13947 Part 4As per IS : 13947 Part 4

SELECTION OF BIMETAL OVERLOAD RELAYSSELECTION OF BIMETAL OVERLOAD RELAYS

1 . FIND OUT THE NAME PLATE CURRENT OF MOTOR

OR

CALCULATE THE FULL LOAD CURRENT

I FULL LOAD =

KW * 1000

3 * LINE VOLTAGE * COS

2 . SELECT SUITABLE RELAY RANGE

( ENSURE THAT FULL LOAD CURRENT OF THE MOTOR IS TOWARDS THE MAX. RANGE OF RELAY)

3. ENSURE THAT RELAY TRIP CURVE IS BELOW THE MOTOR WITH STAND CURVE ( IF AVAILABLE )

SETTING OF BIMETAL OVERLOAD RELAYSSETTING OF BIMETAL OVERLOAD RELAYS

1 . FIND OUT THE NAME PLATE CURRENT OF MOTOR

2 . MEASURE THE ACTUAL CURRENT DRAWN BY THE MOTOR.

3. SET THE RELAY AS PER THE ACTUAL CURRENT DRAWN BY THE MOTOR.

( IF THE ACTUAL CURRENT DRAWN IS MORE THAN THE NAME PLATE CURRENT, INVESTIGATE THE CAUSE FOR OVERLOADING )

4. IN CASE OF STAR - DELTA STARTER, CHECK UP WHETHER RELAY IS IN LINE OR PHASE CIRCUIT.

SELECTION AND SETTING OF BIMETAL OVERLOAD RELAYS SELECTION AND SETTING OF BIMETAL OVERLOAD RELAYS

( FOR MOTORS WITH LONG STARTING TIME )

IF THE STARTING TIME OF THE MOTOR IS MORE THAN THE

RELAY TRIP TIME AT STEADY STATE STARTING CURRENT,

NOTE : IN CASE OF MOTOR STARTING TIME BEING MORE THAN THE TRIPPING TIME OF THE RELAY EVEN FOR RELAY WITH DELAYEDTRIPPING CHARECTERISTICS AT STARTING CURRENT , BY PASS THE RELAY DURING STARTING.

1. SELECT A RELAY WITH DELAYED TRIPPING CHARACTERISTICS & ENSURE THAT RELAY TRIP TIME AT STEADY STATE STARTING CURRENT IS MORE THAN THE STARTING TIME OF THE MOTOR.

2. SET THE RELAY AS PER THE ACTUAL CURRENT DRAWN BY THE MOTOR

WHAT IS A MOTOR WHAT IS A MOTOR STARTER ?STARTER ?

IT IS A COMBINATION UNIT OF

CONTACTOR (S) AND A RELAY

USED FOR SWITCHING AND

OVERLOAD PROTECTION OF

THE MOTOR.

FULLY AUTOMATIC STAR DELTA STARTER

HRC FUSEHRC FUSEMAIN APPLICATION AREASMAIN APPLICATION AREAS

AS A S.C.P.D. IN MOTOR STARTER FEEDERSPROTECTION OF LIGHTING & HEATING CIRCUITS

PROTECTION OF TRANSFORMERSPROTECTION OF CABLESBACK-UP TO CBs WHERE FAULT LEVEL EXCEEDS BREAKING CAPACITY OF THE CB

PROTECTION OF SMALL LOADS ON CIRCUITS HAVING HIGH FAULT LEVELS

CONTACT

POP UP INDICATOR

HIGH RESISTANCE WIRE

BODY

FUSE ELEMENT

QUARTZ SAND

CUT SECTION OF HRC FUSECUT SECTION OF HRC FUSE

WHY HRC FUSE ?WHY HRC FUSE ?• EXTREMELY HIGH BREAKING CAPACITY OF UP TO 100KA• VERY FAST OPERATION IN THE EVENT OF HEAVY S/C (CAN INTERRUPT EVEN IN < 5 mSEC)

• CURRENT LIMITING DEVICE - LIMITS S/C CURRENT TO A VALUE LESS THAN PROSPECTIVE PEAK - VERY LOW LET THRU’ ENERGY• NO MAINTENANCE REQUIRED• VERY SMALL/COMPACT SIZE• RELATIVELY LOW COST

SELECTION PARAMETERSSELECTION PARAMETERS

AS PER IS 13703/PART 2 FOR gG FUSE LINK AS PER IS 13703/PART 2 FOR gG FUSE LINK

SIZE In MAXIMUM PERMISSIBLE (A) POWER DISSIPATION (W)

00 100/160 7.5/12 0 160 16 1 250 23 2 400 34 3 630 48 4 1000 90

RATED POWER DISSIPATIONRATED POWER DISSIPATION

SELECTION PARAMETERSSELECTION PARAMETERS

TYPE 1 CO TYPE 1 CO - - ORDINATIONORDINATIONREQUIRES THAT, UNDER SHORT-CIRCUIT CONDITIONS, THE CONTACTOR OR STARTER SHALL CAUSE NO DANGER TO PERSONS OR INSTALATION AND MAY NOT BE SUITABLE FOR FURTHER SERVICE WITHOUT REPAIR AND REPLACEMENT OF PARTS

TYPE 2 CO - ORDINATIONTYPE 2 CO - ORDINATION REQUIRES THAT, UNDER SHORT SHORT-CIRCUIT CONDITIONS, THE CONTACTOR OR STARTER SHALL CAUSE NO DANGER TO PERSONS OR INSTALLATIION AND SHALL BE SUITABLE FOR FURTHER USE. THE RISK OF CONTACT WELDING IS RECOGNIZED, IN WHICH CASE THE MANUFACTURER SHALL INDICATE THE MEASURES TO BE TAKEN AS REGARDS THE MAINTENANCE OF THE EQUIPMENT

CO-ORDINATION WITH STARTERCO-ORDINATION WITH STARTER

SELECTION OF HRC FUSESELECTION OF HRC FUSET

IME

(S

EC

)T

IME

(S

EC

)

CURRENT (n CURRENT (n I IrMrM)) 1 2 3 4 5 6 7 8 9 10

RELAY FUSE CONTACTOR CH. CH. BR. CAPACITY

MOTOR CURRENT

CROSS-OVERPOINT

TYPE 2 COORDINATIONTYPE 2 COORDINATION

SELECTION OF HRC FUSESELECTION OF HRC FUSEPARAMETERSPARAMETERS

RATED VOLTAGERATED VOLTAGE RATED CURRENTRATED CURRENT RATED BREAKING CAPACITYRATED BREAKING CAPACITY TYPE TYPE SIZESIZE TIME-CURRENT CHARACTERISTICSTIME-CURRENT CHARACTERISTICS COORDINATION WITH STARTERCOORDINATION WITH STARTER RATED POWER DISSIPATION DISCRIMINATION WITH OTHER SCPDsDISCRIMINATION WITH OTHER SCPDs

SWITCHES, DISCONNECTORS, SWITCHES, DISCONNECTORS,

SWITCH DISCONNECTOR & SWITCH DISCONNECTOR & FUSE COMBINATION UNITFUSE COMBINATION UNIT

AS PER IS 13947 (PART 3)AS PER IS 13947 (PART 3)

SWITCHSWITCH

A MECHANICAL SWITCHING DEVICE CAPABLE OF MAKING , CARRYING AND BREAKING CURRENTS UNDER NORMAL CONDITIONS WHICH MAY INCLUDE SPECIFIED OPERATING OVERLOAD CONDITIONS.

SHALL BE ABLE TO CARRY FOR A SPECIFIED TIME CURRENTS UNDER SPECIFIED ABNORMAL CONDITIONS SUCH AS THOSE OF SHORT CIRCUIT.

WHY S/W-DISCONNECTOR ?WHY S/W-DISCONNECTOR ?

FOR ISOLATING THE MOTOR FEEDER FOR FOR ISOLATING THE MOTOR FEEDER FOR ANY MAINTENANCE WORKANY MAINTENANCE WORK

CAN BE USED AS BACK-UP SWITCHING CAN BE USED AS BACK-UP SWITCHING DEVICE IN CASE OF EMERGENCIES (LIKE DEVICE IN CASE OF EMERGENCIES (LIKE CONTACTOR WELDING)CONTACTOR WELDING)

POSITIVE OPENING OF MAIN CONTACTSPOSITIVE OPENING OF MAIN CONTACTS ADDITIONAL FACILITIES LIKE DOOR ADDITIONAL FACILITIES LIKE DOOR

INTERLOCK & PADLOCKING INTERLOCK & PADLOCKING

EQUIPMENT DEFINITION FUNCTIONFUNCTION

MAKE - CARRY - BRAEAK ISOLATION & CARRY MAKE-CARRY- BREAKMAKE - CARRY - BRAEAK ISOLATION & CARRY MAKE-CARRY- BREAK CURRENT & ISOLATIONCURRENT & ISOLATION

SWITCH DISCONNECTOR SWITCH - DISCONNECTOR

SWITCH - DISCONNECTOR - SWITCH FUSE FUSE DISCONNECTOR - FUSE

FUSE - SWITCH FUSE - DISCONNECTOR FUSE - SWITCH -

DISCONNECTOR

UTILIZATION CATEGORYUTILIZATION CATEGORY

AC20 AC20 A A AC 20 AC 20 BB CONNECTING & DIS- CONNECTING CONNECTING & DIS- CONNECTING UNDER NOLOAD CONDITIONSUNDER NOLOAD CONDITIONS

AC 21 AC 21 A A AC 21 AC 21 B B SWITCHING OF RESITIVE LOADS SWITCHING OF RESITIVE LOADS INCLUDING MODERATE OVERLOADSINCLUDING MODERATE OVERLOADS

AC 22 AC 22 A A AC 22 AC 22 B B SWITCHING OF MIXED RESISTIVE SWITCHING OF MIXED RESISTIVE & INDUCTIVE LOADS , INCLUDING& INDUCTIVE LOADS , INCLUDING MODERATE OVERLOADSMODERATE OVERLOADS

AC 23 AC 23 AA AC 23 AC 23 BB SWITCHING OF MOTOR OR HIGHLY SWITCHING OF MOTOR OR HIGHLY INDUCTIVE LOADSINDUCTIVE LOADS

FREQUENT INFREQUENT TYPICALFREQUENT INFREQUENT TYPICAL

OPERATION OPERATION APPLICATIONOPERATION OPERATION APPLICATION

Motor Protection Circuit Breakers(MPCBs)

ADVANTAGES :

• FUSELESS PROTECTION SYSTEMS WITH LOW DOWN TIME

• INTEGRATED COMPREHENSIVE PROTECTION

• LOWER LET THROUGH ENERGY

• COMPACT

• AVAILABILITY OF VARIOUS ACCESSORIES

• HIGH ELECTRICAL LIFE

• HIGH BREAKING CAPACITY

• EASE OF CO-ORDINATION

Accessories with MPCB

• AUX. CONTACTS * INDICATE ---- ON / OFF POSITION ---- TRIP same as OFF

• TRIP INDICATING AUX. CONTACTS *S/C signaling contacts *O/L signaling contacts

• SHUNT RELEASE ----- REMOTE TRIPPING • UNDER VOLTAGE RELEASE• DOOR COUPLING HANDLE

Type 2 co-ordination

MOTORCURRENT

T IME

CURRENT14In5-6In

MPCB

CROSS OVERPOINT ( IN BUILT )

Application : Stand alone devicedetermination of cross over point

MPCB SCHEME 1

I>

M

MPCB

MOTOR

SCHEME IS RECOMMENDED WHEN SWITCHING OF MOTOR IS INFREQUENT

MPCB PROVIDES :

* PROTECTION AGAINST SHORT CIRCUIT

* PROTECTION AGAINST OVER LOAD + S/P

* SWITCHING OF MOTOR

MPCB SCHEME 2

I>

M

MPCB

MOTOR

SCHEME IS RECOMMENDED WHEN SWITCHING OF MOTOR IS FREQUENT

MPCB PROVIDES :

* PROTECTION AGAINST SHORT CIRCUIT

* PROTECTION AGAINST OVER LOAD + S/P

CONTACTOR IS USED FOR

*SWITCHING OF MOTOR UNDER NORMAL CONDITION

CONTACTOR

MPCB SCHEME 3

I>

M

MPCB

MOTOR

MPCB PROVIDES :

* PROTECTION AGAINST SHORT CIRCUIT

O/L RELAY PROVIDES :

* PROTECTION AGAINST OVER LOAD + S/P

CONTACTOR IS USED FOR

* SWITCHING OF MOTOR UNDER NORMAL CONDITION

* SWITCH OFF MOTOR ON TRIP COMMAND

FROM RELAY OUTPUT

CONTACTOR

O/L RELAY