Mcb 3g2f73

Miniature Circuit Breakers (MCB) Multi 9

Definition Main functions

 Protect cables against overloads and short circuits  Let the current flow without overheating on cables  Open and close a circuit under rated current  Protect against insulation faults (see earth leakage protection module)

 Symbol

Miniature circuit = switch + trip unit breaker (MCB) 4

Customer Training - Freddy Suhartono - April 2000 - English

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Definition A Multi 9 circuit breaker has:

 A mechanical system to open and close the circuit  A bimetal strip to act against overloads  A magnetic trip to act against short circuits

Miniature circuit = switch + trip unit breaker (MCB) 4

Customer Training - Freddy Suhartono - April 2000 - English

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Definition Main performances

 It has standardized modular dimensions   125   50 kA   440 V CA

It fits in your pocket... 4

Customer Training - Freddy Suhartono - April 2000 - English

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Definition  The modular design meets 2 criteria:  mounting on a 35 mm symmetrical rail  dimensions - modules in widths of 17.5 mm + 0.5 - 0 - external part = 45 mm - depth between 55 and 70 mm

 Multi 9 standard  Multi 9 switchgear comes in 9 mm pitch 4

44 maxi 21.3

81 45 maxi

width

symmetrical rail

depth

Customer Training - Freddy Suhartono - April 2000 - English

external part

10 maxi

35

60

5

The technology Active parts NC100 / NC125 terminal

terminal

bimetral strip

fixed

strip braid

moving strip braid

moving magnetic trip load side terminal

magnetic trip strip braid bimetal strip load side terminal

4

Customer Training - Freddy Suhartono - April 2000 - English

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Overload protection  A bimetal strip is used:  to protect the cable against overloads  symbol:  principle of the bimetal: in a Multi 9 circuit breaker 4 NC45

NC100 / NC125

bimetal tripping bar tripping bar

bimetal screw calibration strip braid

Customer Training - Freddy Suhartono - April 2000 - English

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Overload protection  Thermal tripping curve

 the "thermal" part of the tripping curve must be in accordance with the standard

t (s) tripping

no tripping

destruction of bimetal accuracy

Legend: In = rated current Ind = no tripping current Id = tripping current 4

Customer Training - Freddy Suhartono - April 2000 - English

In

Ind Id

I/In

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Overload protection  Temperature derating  our circuit breakers do not have temperature compensation  if the calibration temperature is different from the ambient temperature: derating is required

Simultaneous multi-pole tripping 4

Customer Training - Freddy Suhartono - April 2000 - English

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Short-circuit protection Short-circuit current is given as RMS or peak (Isc or Îsc) RMS = Root Mean Square in symmetrical DC (with PF = I) Short-circuit protection must limit thermal stress in the cable in order to prevent cable damage (which may reach vaporization of the copper in some cases)

Comments slide 29 Customer Training - Freddy Suhartono - April 2000 - English

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Short-circuit protection The arc in Multi 9 circuit breakers NC45

NC100 / NC125

arcing horn

"By-" technique for the protection of sensitive parts of the circuit breaker DC breaking is difficult

Customer Training - Freddy Suhartono - April 2000 - English

arcing horn

"By-" technique for the protection of sensitive parts of the circuit breaker (magnetic trip)

2 breaking techniques used by Multi 9 4

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Short-circuit protection Magnetic tripping curve t (s)

destruction of the solenoid

tripping

no tripping

Legend: Ind = no tripping current Id = tripping current

Ind Id

I/In

Our curves are instantaneous tripping curves 4

Customer Training - Freddy Suhartono - April 2000 - English

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The magnetic tripping levels with high inrush current: like LV/LV transformers  C Curve  5 and 10 In control and protection of circuits with high short-circuit current in industrial and domestic distributions  D and K curves tripping betwen  tripping: 10 to 14 In; more particulary adopted for installations with high inrush currents like LV/LV transformers

 B curve  3 and 5 In protection low short-circuit current generators G

Customer Training - Freddy Suhartono - April 2000 - English

 Z curve  2.4 to 3.6 In protection against electronic circuits

 MA curve  12 In; protection only against short-circuit and high inrush currents such as motors, coil 4

M

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Marking  Front marking:

 Side marking:

Circuit breaker marking is governed by strict rules in accordance with the standards and decisions made by the manufacturer 4

Customer Training - Freddy Suhartono - April 2000 - English

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Choosing a circuit breaker In conclusion  A Multi 9 circuit breaker is determined by:  rating  breaking capacity  number of poles  voltage  tripping curve  standard  frequency  type of load 4

Customer Training - Freddy Suhartono - April 2000 - English

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Auxiliaries: C60  SD: alarm switch  MX + OF: shunt trip  MN: undervoltage release

 4 types of auxiliaries for our

Multi 9 circuit breakers  OF: indication switch

SD

MX+OF

MN

C60

51/3

52/3

54/3

53/3

44/3

OF

54 mm maxi

The information is transmitted via a mechanical link C60/NC100 and NC125 auxiliaries are not compatible 4

Customer Training - Freddy Suhartono - April 2000 - English

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Auxiliaries: NC100 - NC125  4 types of auxiliaries for our

 SD: alarm switch  MX + OF: shunt trip  MN: undervoltage release

MN or MX+OF or Vigi

27/3

35/3

NC100H

SD

34/3

33/3

OF

36/3

Multi 9 circuit breakers  OF: indication switch

The information is transmitted via a mechanical link C60/NC100 and NC125 auxiliaries are not compatible 4

Customer Training - Freddy Suhartono - April 2000 - English

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End presentation

Customer Training - Freddy Suhartono - April 2000 - English

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