miniature circuit breakers (mcb) multi 9
DESCRIPTION
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 - PowerPoint PPT PresentationTRANSCRIPT
Miniature Circuit Breakers (MCB)Multi 9
Customer Training - Freddy Suhartono - April 2000 - English 2
Protect cables againstoverloads 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 leakageprotection module)
DefinitionMain functions
Miniature circuit = switch + trip unit breaker (MCB)
Symbol
Customer Training - Freddy Suhartono - April 2000 - English 3
A mechanical system to open and close the circuit
A bimetal strip to act against overloads
A magnetic trip to act against short circuits
DefinitionA Multi 9 circuit breaker has:
Miniature circuit = switch + trip unit breaker (MCB)
Customer Training - Freddy Suhartono - April 2000 - English 4
It has standardized modular dimensions
125A
50 kA
440 V CA
DefinitionMain performances
It fits in your pocket...
Customer Training - Freddy Suhartono - April 2000 - English 5
Definition
Multi 9 standard Multi 9 switchgear comes in 9 mm pitch
width
symmetricalrail
externalpartdepth
6010 maxi
3545maxi
44 maxi
21.3
81
The modular design meets 2 criteria:
mounting on a 35 mmsymmetrical rail
dimensions- modules in widths of 17.5 mm + 0.5 - 0- external part = 45 mm- depth between 55 and 70 mm
Customer Training - Freddy Suhartono - April 2000 - English 6
The technologyActive parts
C60N NC100 / NC125
terminal
fixed contact
movingcontact
strip braid
magnetictrip
load side terminal
terminal
bimetral strip
strip braid
movingcontact
magnetic trip
load side terminal
strip braidbimetal strip
Customer Training - Freddy Suhartono - April 2000 - English 7
Overload protection
bimetal
tripping barbimetal
tripping bar
screwcalibration
stripbraid
NC45 NC100 / NC125
A bimetal strip is used: to protect the cable against overloadssymbol: principle of the bimetal: in a Multi 9 circuit
breaker
Customer Training - Freddy Suhartono - April 2000 - English 8
Thermal tripping curve
the "thermal" part of thetripping curve must be
inaccordance with the
standard
Overload protection
Legend:In = rated currentInd = no tripping currentId = tripping current
tripping
notripping
destructionof bimetal
accuracy
t (s)
I/InIn Ind Id
Customer Training - Freddy Suhartono - April 2000 - English 9
Overload protection
Simultaneous multi-pole tripping
Temperature derating our circuit breakers do not have temperature
compensation if the calibration temperature is different from
the ambient temperature: derating is required
Customer Training - Freddy Suhartono - April 2000 - English 10
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 11
Short-circuit protection
"By-pass" technique for the protection of sensitive partsof the circuit breaker DCbreaking is difficult
"By-pass" technique for the protection of sensitive parts of the circuit breaker (magnetic trip)
The arc in Multi 9 circuit breakers
2 breaking techniques used by Multi 9
arcinghorn arcing
horn
NC45 NC100 / NC125
Customer Training - Freddy Suhartono - April 2000 - English 12
Short-circuit protectionMagnetic tripping curve
Our curves are instantaneous tripping curves
Legend:Ind = no tripping currentId = tripping current
destructionof the solenoid
trippingnotripping
t (s)
I/InInd Id
Customer Training - Freddy Suhartono - April 2000 - English 13
B curve 3 and 5 In protection
low short-circuit current generators
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 currentin industrial and domestic distributions
D and K curves tripping betwen tripping: 10 to 14 In; more particulary
adopted for installations with highinrush currents like LV/LV transformers
Z curve 2.4 to 3.6 In protection against
electronic circuits
MA curve 12 In; protection only against
short-circuit and high inrush currentssuch as motors, coil
G
M
Customer Training - Freddy Suhartono - April 2000 - English 14
Side panel marking:
Marking
Front panel marking:
Circuit breaker marking is governed by strict rules in accordance with the standards and decisions made by the manufacturer
Customer Training - Freddy Suhartono - April 2000 - English 15
Choosing a circuit breakerIn conclusion
A Multi 9 circuit breaker is determined by:
rating
breaking capacity number of poles
voltage
tripping curve standard
frequency
type of load
Customer Training - Freddy Suhartono - April 2000 - English 16
Auxiliaries: C60
SD: alarm switch MX + OF: shunt trip MN: undervoltage release
The information is transmitted via a mechanical link C60/NC100 and NC125 auxiliaries are not compatible
54 mm maxi
4 types of auxiliaries for ourMulti 9 circuit breakers
OF: indication switch
MX+OFOF SD C60
44/3
MN
51/3
52/3
54/3
53/3
Customer Training - Freddy Suhartono - April 2000 - English 17
Auxiliaries: NC100 - NC125
The information is transmitted via a mechanical link C60/NC100 and NC125 auxiliaries are not compatible
NC100H MX+OFor Vigi
MN orOF SD
33/3
34/3
35/3
36/327
/3
SD: alarm switch MX + OF: shunt trip MN: undervoltage release
4 types of auxiliaries for ourMulti 9 circuit breakers
OF: indication switch
Customer Training - Freddy Suhartono - April 2000 - English 18
End presentation