Well as better function. Also, you can adjust the current setting as well as the time setting in the modes of case breaker.
MOULD CASE CIRCUIT BREAKER is Indicated by a Small Curve Followed by the Two Lines
The input and output of the mored set case will be bottom and top size.
MCCB Consist of 9 Different Parts Such
Arc Chute
MOVING CONTACT
Operating mechanism
Base cover
Terminal Connector
Overload trip or bimetallic contact
Handle knob
Manual Trip Button
CT -Current Transformer Assembly
Let ’s see the defaled explanation of the construction of mccb. BeFore Refer the picture.
Arc Chute:
MOVING CONTACT:
Operating mechanis:
It deals with the control opening and closing process. The speyd of the operating mechanis does not depend on how faster is moved.
It will be associated with the relay operation mechanism.
Also, Breakers are designed with the test Mechanism Which Alows the Breaker to Trip Manually.
Base Cover:
Terminal Connector
no loose contact between the terminal.
If the rating of the mccb is more than 400Amps Means, the terminal connector will be equiped with an assembly,
They are using to connect McCB with the Higher Rating Cables SINCE The Cable Size Will Be Bigger for the Higher Current Ratings.
Bimetallic contal:
A temporary-sensitive component, The Composition of Steel and Copper Material is using As Bimetalic Contact. Bimetalic contact is assembled in server.
HENCE, The Full Line Current of the Breaker Always Will Be Passed Through the Bimetalic Contory.
It is using to try the breaker under an overload consition.
Handle knob:
It is using to close or open the control manually. Also, you cannot force to stop the breaker tripping by holding knob at the top size.
Handle Knob Indicates the Breaker Status, what it is in on position or off posity.
If the handle is in the update diary, it is class on position, if it is in the double position, the ame class office. If it is tripped, then the handling center
Manual Trip Button:
A Red Color Button that is associated with the operating mechaanism is Called a manual trip button. It is mainly used to try the breaker manually.
Current Transformer & Trip Unit Assembly:
A set ofurrent transformer is mount inside of the breaker as shown in the Above-Mentioned Figure,,,,,,
The output of the ct will be connected to the relay tripping unit. It is the brain of the mccb.
The McCB Working Principle is Simple. Let us take the three forms such such is an overload, short circuit, and econom fault.
Overload trip
A Flow of Current That Exceeds The Rated Current with Predefined Time Limit Such a Fault is Called Overload. Actually, it is not a fault, it is a conDition.
The breaker. Refer to the picture
Also, bimetalic contact will not allow the breaker to reset instantly. SINCE IT TAKES SOME TIME to Reach its Original State.
Over Load, The Setting Will Be 80% to 100% of the Full Load Current and the Dame Depending Upon Your Load Demand. But the time delay will be 10 to 15Secs.
Short Circuit / Instantaneous / Earth Fault TRIP:
The Typical Setting of a Short Circuit Will Be 2.5Times of the Overload Setting and the Time Delay Will Be 0.2 to 0.5 SECS.
The type setting of an instantaneous fault will be 4 Times of the overload setting and the time delay will be zero.
Earth Fault Leakage Trip:
Earth Leakage Protection is Quite Different from Other Protection. It a tailor-made one. It requires adDitional ct space.
Flow is higher than the allowable limit means, the mccb trip the circuit.
According to the tripping types, the McCB is divided into six categories.
Typed: Suitable for Heavy Starting Current Applications Such as Motors, Pumps, Lifsts, ETC. It has operating range of 10 Times with the time of 0.04 to 3 seaconds
Typek: Operates when thecurrent Goes to 10 Times ITS FULL LOAD CURRENT. Operating Time for Type K MCCB IS 0.04 to 5 Seconds. They Are the Best Suitable Feeder Protection.
Typez: Type Z McCBS Are Very Sensitive and They Can ALLOW 1.5 to 3 Times The Full Load Current.
The ManuFacture PRovides Some Technical Data that is used to understand the chacristics of the mccb. Let us see.
Inm – Rated Frame Current => The Maximum Allowable Current Through The McCB WHEREAS MCCB Operates Under the Stable Region.
In => Rated Current => Functional Tripping Range of the Breaker.
UI => Rated Insulation Voltage => The Maximum Allowable Voltage Ranges of the Breaker.
UE => Rated Voltage => Functional Voltage of the Breaker
UIMP => Rated Impulse withstand Voltage => Surge Voltage of the MCCB, The Standard Size for Impulse Testing is 1.2/50μs
ICS => Short Circuit Breaking Capacity => The Maximum Amount of Short Circuit Current where the breakr can break the city with physical damage.
Advantage
OCCUPY Less Space in the Electrical Panel
Cheapr than acBS
Adjustable Current Settings
MaIntenance-free
Fault Clearing Times are faster than the fuse units.
No need to keep the spares, hence the inventory will be reduced.
Suitable for indultric and Commercial Applications
Disadvantages
LISG FAULT NEEDS to Tailor It.
Needs add-on for getting feedback from the mccb.
Not suitable domStic Application.
Life span is less as compared with accept
Not suitable for high voltage applications.
Applications:
I have used it for many inDuction Motor ’s Starters Such as Star-Delta, DOL Starter, Soft Starter ETC, Soft Starter ETC, Soft Starter ETC, Soft Starter Etc, Soft Starter ETC, Soft Starter ETC, Soft Starter ETC, Soft Starter ETC, Soft Starter ETC, Soft Starter ETC,
Panel Incomer Applications,
Distribution Feeder
Can we use for the dc application?
Yes, we can use it, but it will not try on short circuit fault.
2. Best Suitable Type McCB for The Star-Delta Starter?
Type d, since the operationing range is high, they can tolerate the high starting current of the reason motor.
3. How to chooose the McCB?
While Purchasing mccb, you have to take care of rated full loadurrent, types of mccb, ICS.
4. Who is the best manuFacture of McCB?
Siemens is the best one. I have used in my many applications, they are user friendly.
5. How to reset the mccb:
While tripping the mccb, the handle knob will be in the middle position, in order to reset the breaker, the knob at the download. It will get reset.
If support of Electronic McCB You have any questions, leave a comment below …