presentation on miniature circuit boards

a file and presentation on miniature circuits board

1. Vadodara institute of engineering,kotambi
NAME:NAFISKHANPATHAN(13ELEE181)
BARIYA VIPUL(13ELEE182)
PATEL AMIT(13ELEE180)
BRANCH:EE-2
PPT OF EEE

2. Miniature circuit breaker(mcb)

3. Miniature Circuit Breakers (MCB)
Multi 9

4. 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)
Definition
Main functions
Miniature circuit = switch + trip unit breaker (MCB) 4
Symbol

5. A mechanical system to open and close the
circuit
A bimetal strip to act against overloads
A magnetic trip to act against short circuits
Definition
A Multi 9 circuit breaker has:
Miniature circuit = switch + trip unit breaker (MCB) 4

6. It has standardized modular dimensions
125A
50 kA
440 V CA
Definition
Main performances
It fits in your pocket... 4

7. Definition
Multi 9 standard
Multi 9 switchgear comes in 9 mm pitch 4
width
symmetrical
rail
external
partdepth
6010 maxi
3545
maxi
44 maxi
21.3
81
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

8. The technology
Active parts
C60N NC100 / NC125
terminal
fixed contact
moving
contact
strip braid
magnetic
trip
load side
terminal
terminal
bimetral strip
strip braid
moving
contact
magnetic trip
load side
terminal
strip braid
bimetal strip
4

9. Overload protection
bimetal
tripping bar
bimetal
tripping bar
screw
calibration
strip
braid
NC45 NC100 / NC125
A bimetal strip is used:
to protect the cable against overloads
symbol:
principle of the bimetal: in a Multi 9 circuit
breaker4

10. Thermal tripping curve
the "thermal" part of the
tripping curve must be in
accordance with the
standard
Overload protection
Legend:
In = rated current
Ind = no tripping current
Id = tripping current 4
tripping
no
tripping
destruction
of bimetal
accuracy
t (s)
I/InInIndId

11. Overload protection
Simultaneous multi-pole tripping 4
Temperature derating
our circuit breakers do not have temperature
compensation
if the calibration temperature is different from
the ambient temperature: derating is required

12. 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

13. Short-circuit protection
"By-pass" technique for the
protection of sensitive parts
of the circuit breaker DC
breaking 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 4
arcing
horn arcing
horn
NC45 NC100 / NC125

14. Short-circuit protection
Magnetic tripping curve
Our curves are instantaneous tripping curves 4
Legend:
Ind = no tripping current
Id = tripping current
destruction
of the solenoid
tripping
no
tripping
t (s)
I/InIndId

15. 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 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
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
G
M

16. 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 4

17. 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

18. 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 4
54 mm maxi
4 types of auxiliaries for our
Multi 9 circuit breakers
OF: indication switch
MX+OF
OF SD C60
44/3
MN
51/352/354/3
53/3

19. Auxiliaries: NC100 -NC125
The information is transmitted via a
mechanical link C60/NC100 and NC125
auxiliaries are not compatible 4
NC100H MX+OF
or Vigi
MN orOF SD
33/3 34/3
35/3
36/3
27/3
SD: alarm switch
MX + OF: shunt trip
MN: undervoltage release
4 types of auxiliaries for our
Multi 9 circuit breakers
OF: indication switch

20. THANKYOU