Introduction of Circuit breakers sides. CB are automated electrical switches designed to offer protection to electrical circuits from potential overload or short circuiting of the circuits. Circuit breaker devices have the ability of being reset either manually or automatically for normal operation to resume. The devices are designed in various sizes and shapes depending on the type of electrical circuit they are used in. Small circuit breakers are used to protect small equipment like household appliances and big devices are used to offer protection for high voltage circuits. Types of circuit breakers Miniature circuit breakers MCB is the standard acronym for miniature circuit breakers. These are electric switches used in low voltage electric currents to protect electrical cables and lines against thermal overload and short circuiting brought about by electromagnetic. The trip characteristics in such devices cannot be adjusted and they normally function through thermal or thermal- magnetic based operations. Miniature circuit breakers protect the equipment they are used in from excessive temperature and destruction brought about by potential short- circuiting. Molded case circuit breakers (MCCB) Molded case circuit breakers are types of protective electric switches having an electric current rating of up-to 2500A. The devices just like miniature circuit breakers use thermal or thermal- magnetic operation. The trip current found in these electric protective switches is highly adjustable to meet the needs of the appropriate electric circuit. These devices are common in combination starters, panelboards, switchboards and control panels. Motor protective circuit breakers These are special types of protective electric switches used specifically for motor based applications. They provide both overload and short circuit protection for individual motor loads they are used in. Motor protective circuit breakers can be used together with contactors to provide complete motor protection that is highly reliable. By doing so it is possible to curb and eliminate any form of malfunction likely to arise. Motor protective circuit breakers acre made of a combination protection unit consisting of switches, overload relays or short circuit protective device functions. Vacuum circuit breakers Vacuum circuit breakers are electrical devices that offer protection to electrical circuits and equipment or machinery by use of two electrical contacts that are enclosed in a vacuum. Vacuum circuit breaker devices are specially characterized by having minimal arching properties. The devices are used mainly in medium voltage applications. One of the electrical contacts is permanently fixed in a specific position while the other is left to roam freely. When the circuit breaker detects potential danger, the freely moving contact is made to pull away from the fixed one hence breaking the electric circuit preventing short circuiting or machinery damage.

1. THE BEST VIRTUAL EXPO FOR INDUSTRIAL AUTOMATION
PRODUCTS
Introduction to :
Circuit breakers

2. Circuit breakers
A circuit breaker is an automatically
operated electrical switch designed to protect an electrical
circuit from damage caused by overload or short circuit. Its
basic function is to detect a fault condition and interrupt
current flow. Unlike a fuse, which operates once and then
must be replaced, a circuit breaker can be reset (either
manually or automatically) to resume normal operation.
Miniature circuit breakers Molded case circuits brakers
Motor protective circuit breakers Vacuum
Thermal circuit-breakers High voltage
Medium voltage Air
Outdoor Residual current

3. M i n i a t u r e c i r c u i t b r e a k e r s
Miniature circuit breakers are types of low-
voltage circuit breakers that are designed to
protect an electric circuit in cases of overloads
that are more than 100A or in cases of short
circuiting of electric current.
These types of electric circuit breakers use either
thermal or thermal- magnetic based operations.

4. M o l d e d c a s e c i r c u i t
b r e a k e r s
Molded case circuit breakers are types of
protective electrical switches with a rating
electrical current of up to 2,500A. Molded
case circuit breakers normally use thermal or
thermal magnetic operation elements to open
or close electrical circuits protecting
machinery from potential damage.
These types of electrical circuit breakers are
used to a larger extent in control panels,
switchboards, motor control centers and
individual enclosures.

5. M o t o r p r o t e c t i ve c i r c u i t
b r e a k e r s
Motor protective circuit breakers are electrical
switches whose main purpose is to protect
circuits found in electric motor related
machinery. These types of protective electrical
switches are normally a combination protection
unit that may have functions like that of a switch,
over load relay or those of short circuit
protective devices.
To achieve complete protection and eliminate any
form of malfunction, motor protective circuit
breakers are used with a contractor hence
achieving complete motor protection.

6. Va c u u m c i r c u i t b r e a k e r s
Vacuum circuit breakers are electrical safety
devices that has two electrical contacts enclosed
in a vacuum.
One of the contacts is fixed to a specific position
while the other is free to move from one point to
another hence in case the vacuum circuit breaker
senses potential danger, the movable contact
pulls away from the fixed contact creating a
vacuum hence breaking the circuit.

7. Thermal circuit-breaker
This are electrical safety devices that have the ability
to break a given circuit through switching it off
automatically if the temperature rises above the
normal one that it is supposed to work within.
Thermal circuit breakers are also known
as commercial circuit breakers or circuit protectors in
various electrical or manufacturing industries.

8. High voltage circuit breakers
High voltage circuit breakers are mechanical
switching safety electrical devices that mainly
connect and break current circuits and are used
to carry the nominal current in closed positions
from one point to another.
These types of circuit breakers are mainly used
in power transmission applications and are
relatively expensive as compared to other types
of circuit breakers.

9. Medium-voltage circuit breakers
Medium-voltage circuit breakers are safety devices
that mainly use current sensing protective relays to
decide on the most appropriate action opening
electrical circuits to prevent damage of machinery or
electrical equipment Medium- voltage circuit
breakers are normally rated between 1 and 72kV.
These are the second in terms of handling current
following high voltage circuit breakers. These types
of circuit breakers may be either assembled into
switch gear line ups to be used in indoors
applications or installed outdoors in various
substations as individual components.

10. Air circuit breakers
Air circuit breakers are electrical safety devices that
usually operate in air at a given atmospheric
pressure. Air circuit breakers are rated up to a
maximum of 10,000A in the electrical field. Air
circuit breakers can be categorized into either plain
air circuit breakers or air blast circuit breakers.
Air blast circuit breakers are used for the system
voltage of of 245 KV and 420 KV where faster
breaker operation is required to prevent current
flow when hazardous situations arise.

11. Outdoor circuit breakers
Outdoor circuit breakers are types of electrical
safety devices that are mainly used to protect
electrical circuits from high voltage or voltage
fluctuations in outdoor applications. They can be
identified as either live tank or dead tank outdoor
circuit breakers according to their physical
structural design. The main difference between
the circuit breakers is that the switching device
surrounded at potential ground in dead tank
circuit breakers is at ground potential while that
of a live tank is at a potential above ground.

12. Residual current circuit
breakers
Residual current circuit breakers are also known
as residual current devices. These are electrical
wiring safety devices that disconnects circuits in
cases involving electrical current imbalance between
the energized line conductors and the neutral
conductors This ensures protection against earth-
leakage that may exist on electric circuits protecting
people and electric against direct or indirect contact.

13. VALVES
Contact details :
VISUM Ltd.
Letna 40
040 01 Kosice
Slovakia - E.U.
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