A circuit breaker is an automatically operated electrical switch designed to protect an electrical
circuit from damage caused by excess current from an overload or short circuit or in no-load
condition.
In this video, I will go to show you Different types of Circuit Breakers.
Firstly we classify the circuit breakers according to the voltage levels they can operate on.
So there are three most used types of circuit breakers in this category.
1.
Low voltage circuit breaker.
2.
Medium voltage circuit breaker.
3.
High voltage circuit breaker.
Low Voltage Circuit Breaker:
Low-voltage breaker types are common in domestic, commercial, and industrial application, and
include: • MCB, Miniature circuit breaker, rated
current not more than 100 Amp.
Trip characteristics normally not adjustable.
Thermal or thermal-magnetic operation.
Breakers illustrated above are in this category.
• MCCB, Molded Case Circuit Breaker, rated current up to 2,500 Amp.
Thermal or thermal-magnetic operation.
Trip current may be adjustable in larger ratings.
• Low-voltage power circuit breakers can be mounted in multi-tiers in low-voltage switchboards
or switchgear cabinets.
Medium Voltage Circuit Breaker:
Medium-voltage circuit breakers rated between 1 and 72 KV may be assembled into metal-enclosed
switchgear line ups for indoor use or maybe individual components installed outdoors in
a substation.
Air-break circuit breakers replaced oil-filled units for indoor applications, but are now
themselves being replaced by vacuum circuit breakers up to about 40.5 KV.
High Voltage Circuit Breaker:
Electrical power transmission networks are protected and controlled by high-voltage breakers.
The definition of high voltage varies but in power transmission work is usually thought
to be 72.5 KV or higher.
High-voltage breakers are nearly always solenoid-operated, with current sensing protective relays operated
through current transformers.
In substations the protective relay scheme can be complex, protecting equipment and buses
from various types of overload or ground or an earth fault.
High-voltage breakers are broadly classified by the medium used to extinguish the arc:
There are four types in this category.
1.
Air circuit breaker.
2.
Oil circuit breaker.
3.
SF6 circuit breaker.
4.
Vacuum circuit breaker.
Air Circuit Breaker:
Air Circuit Breaker is an electrical device used to provide Overcurrent and short-circuit
protection for electric circuits over 800 Amps to 10K Amps.
These are usually used in low voltage applications below 450V.
Air break circuit breaker the arc is initiated and extinguish in substantially static air
in which the arc moves.
Oil Circuit Breaker:
Oil circuit breaker is such type of circuit breaker which used oil as a dielectric or
insulating medium for arc extinction.
In oil circuit breaker the contacts of the breaker are made to separate within an insulating
oil.
SF6 Circuit Breaker:
A circuit breaker in which SF6 under pressure gas is used to extinguish the arc is called
SF6 circuit breaker.
SF6 gas has excellent dielectric, arc quenching, chemical and other physical properties which
have proved its superiority over other arc quenching mediums such as oil or air.
Vacuum Circuit Breaker:
A vacuum circuit breaker is a kind of circuit breaker where the arc quenching takes place
in vacuum medium.
The operation of switching on and closing of current carrying contacts and interrelated
arc interruption takes place in a vacuum chamber in the breaker which is called vacuum interrupter.
Dear sir, Thanks for watching the video.
For more updates please subscribes to our channel Learning Engineering, and get a notification
to press the bell icon.