Features, Working principles, and differences of Miniature Circuit Breaker(MCB), Moulded Case Circuit Breaker(MCCB) and Residual Current Circuit Breaker (RCCB) are explained in basic terms.
A switchgear or electrical switchgear is a generic term which includes all the switching devices associated with mainly power system protection. It also includes all devices associated with control, metering and regulating of electrical power system. Assembly of such devices in a logical manner forms a switchgear. This is the very basic definition of switchgear.
⋗To get more with details
https://www.youtube.com/channel/UC2SvKI7eepP241VLoui1D5A
Every power supply depends upon a reliable infeed of electricity. Air circuit breakers reliably protect electrical installations against damage or fire as a result of short circuits, ground faults, or overload faults.
CIRCUIT BREAKER
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, by interrupting continuity, to immediately discontinue electrical flow. Unlike a fuse, which operates once and then has to be replaced, a circuit breaker can be reset (either manually or automatically) to resume normal operation. Circuit breakers are made in varying sizes, from small devices that protect an individual household appliance up to large switchgear designed to protect high voltage circuits feeding an entire city.
The apparatus used for switching, controlling & protecting the electrical circuits & equipments are known as switchgear.
The switchgear equipments is essentially used with switching & interrupting currents either under normal or abnormal operating condition.
It consists of devices such as switches, fuses, circuit breakers, relays etc.
Basically every electric circuit needs a switching device & a protecting device.
The standard electromechanical RCCBs are designed to work with normal waveform power and cannot be guaranteed to work if any standard waveforms are generated by loads. The most common is the rectified half-wave waveform, sometimes referred to as pulsed direct current, generated by speed control devices, semiconductors, computers, and even dimmers.
A switchgear or electrical switchgear is a generic term which includes all the switching devices associated with mainly power system protection. It also includes all devices associated with control, metering and regulating of electrical power system. Assembly of such devices in a logical manner forms a switchgear. This is the very basic definition of switchgear.
⋗To get more with details
https://www.youtube.com/channel/UC2SvKI7eepP241VLoui1D5A
Every power supply depends upon a reliable infeed of electricity. Air circuit breakers reliably protect electrical installations against damage or fire as a result of short circuits, ground faults, or overload faults.
CIRCUIT BREAKER
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, by interrupting continuity, to immediately discontinue electrical flow. Unlike a fuse, which operates once and then has to be replaced, a circuit breaker can be reset (either manually or automatically) to resume normal operation. Circuit breakers are made in varying sizes, from small devices that protect an individual household appliance up to large switchgear designed to protect high voltage circuits feeding an entire city.
The apparatus used for switching, controlling & protecting the electrical circuits & equipments are known as switchgear.
The switchgear equipments is essentially used with switching & interrupting currents either under normal or abnormal operating condition.
It consists of devices such as switches, fuses, circuit breakers, relays etc.
Basically every electric circuit needs a switching device & a protecting device.
The standard electromechanical RCCBs are designed to work with normal waveform power and cannot be guaranteed to work if any standard waveforms are generated by loads. The most common is the rectified half-wave waveform, sometimes referred to as pulsed direct current, generated by speed control devices, semiconductors, computers, and even dimmers.
MCB stands for Miniature Circuit Breaker. It automatically switches OFF electrical circuit during any abnormal condition in the electrical network such as overload & short circuitconditions.MCCB stands for Molded Case Circuit Breaker. It is another type of electrical protection device which is used when load current exceeds the limit of a miniature circuit breaker. The MCCB provides protection against overload, short circuit faults and is also used for switching the circuits.
Text Preprocessing is the first step before converting text data into vectors for NLP-based models. This step can also get complicated as text data is not always friendly.
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CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
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When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
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Author: Robbie Edward Sayers
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(C) 2024 Robbie E. Sayers
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
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A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
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3. • It is electrically designed switching device that can perform
automatic operation.
• It used as protection device that interrupts high current flow
and can be used as isolators.
• Reasons: Protection from overcurrent due to overload or short
circuit.
• Automatic action is executed when a fault is detected and
causes to trip its switch.
• There are different types of circuit breakers designed for
different risks of exposure.
8. MINIATURE CIRCUIT BREAKER (MCB)
• Purpose: It provides protection to the circuits from overcurrent.
• Maximum rating goes up to 63 A.
• It is composed of 3 parts:
1. Thermal Trip Unit
2. Magnetic Trip Unit
3. Manual ON/OFF – Manual switch for maintenance purpose.
9. SELECTION OF MCB
• MCB must have rating of 25% more than the load current that follows through the
circuit that it will protect.
• E.g. 22A will flow through the circuit. Therefore:
22 + 0.25 × 22 = 27.5 A
• Standard rating of MCB: 32 A. So, 32 A MCB will be used for the circuit.
• Power switch which controls MCB will have higher rating than MCB. So power switch
rating = 40 A.
10. THERMAL TRIP UNIT
• Purpose: overload protection.
• E.g. nominal current is 15 A and rating of MCB is 20A.
• If load current is 25A, bimetallic strip will bend as it
exceeds rated current.
• As the strip bends, the switch opens.
• Higher the load current, faster bimetallic strip will
bend and therefore faster the switch will trip and
protect.
• Tripping time according to specifications of 32 A MCB:
64 A – 4 minutes and 96 A – 1 minute.
11. MAGNETIC TRIP UNIT
• Purpose: For short circuit protection.
• If short circuit occurs either at 1 (wire gets shorted) or
2 (load itself gets shorted), heavy current will flow.
• Works on basis of electromagnetic effects. Current
transformer(C.T.) is used to magnetize the coil.
• The magnetic coil in MCCB will cause the switch to
attract towards it and therefore, switch trips.
• Operates at very short time usually few milliseconds.
• Tripping time according to specifications of 32 A MCB:
96 A – less than 4 milliseconds.
12. TYPES OF MCBS (BASED ON MAGNETIC TRIPPING
CURRENT)
Type B Type C Type KType D Type Z
13. TYPES OF MCBS (BASED ON MAGNETIC TRIPPING
CURRENT)
• Let rated or full load current be: 10 A.
• Type B: Trips between 3 and 5 times of full load current i.e. 30 – 50 A. Used for
domestic purposes.
• Type C: Trips between 5 and 10 times of full load current i.e. 50 – 100 A. Used for
industrial purposes.
• Type D: Trips between 10 and 20 times of full load current i.e. 100 – 200 A. Used for
battery charger.
• Type K: Trips between 10 and 15 times of full load current i.e. 100 – 150 A. To protect
from high in rush current for windings of motor and transformers.
• Type Z: Trips between 2 and 3 times of full load current i.e. 20 – 30 A. Used for
control circuits.
14. ADVANTAGES OF MCB OVER FUSE
• MCB automatically switches off the electrical circuit both during overload
and faulty conditions.
• MCB is more sensitive to overcurrent than fuse.
• In case of fault, MCB quickly restoration in its initial state is possible just
by manual switching.
• After switch trips or opens, same MCB can be used again. But fuse will
require replacement.
• It is much safer to handle MCB than fuse electrically.
15. MOULDED CIRCUIT BREAKER
• Its purpose, parts and basic working principles (refer slides number 10 and 11) are
same as that of MCB except that it protects the circuits from much higher
overcurrent.
• Another difference is that current trip level can be varied.
• Current trip level for either thermal unit, magnetic unit or both at once can be
varied.
• Rating up to 1000A. Usually 100A MCCBs are used.
• Used for commercial and industrial purposes only as it is very costly for domestic
purpose.
16. OTHER WORKING PRINCIPLES OF MCCB
• Under Voltage (UV) trip: There are some
components that will not work if voltage is too
low. Therefore, UV is sensed by MCCB and
then switch is tripped.
• Shunt trip: Shunt coil is present in MCCB.
When T switch is pressed, this coil receives
power and MCCB will cause the switch to trip.
Used for emergency or to control MCCB
remotely.
17. Interrupting Capacity: It is the ability to
withstand very heavy current due to short
circuit (𝐼𝑆𝐶) within fraction of time. If 5kA
equals to 𝐼𝑆𝐶, interrupting capacity should
be way higher than that otherwise the
contact will catch fire! Very heavy current
is due to very low impedance in the circuit.
18. ADDITIONAL FUNCTIONS OF
MCCB
• Under/Over frequency trip.
• Over Voltage trip.
• Current unbalance trip: Due to load unbalance.
• Reverse power trip: If power factor is too low, MCCB
trips.
• Power factor trip.
• Reverse phase sequence trip.
19. SELECTION OF MCCB
• Rated Voltage – 400 V.
• Continuous rated current – 100A.
• Breaking current capacity – 20kA, 50kA, 100kA.
• Poles(2(single phase), 3(3 phase 3 wire RYB), 4(3 phase 4 wire RYB N)).
• UV trip
• Shunt trip
• Auxiliary contact: Another switch connected to main contact. When main contact trips,
auxiliary contact is pressed for control indication. Used mainly as alarm. Check slide no. 5 -
small red circled switch.
20. TYPES OF MCCB
Line Protection Distribution Board Protection Solid State trip Motor Protection
21. • Line Protection – General purpose circuit protection. Used for
providing protection to small machines and power distribution in
buildings.
• Distribution Board Protection – It is installed on distribution
boards to protect lightings both indoors and outdoors. It has
compact size. Interrupting capacity – 2.5kA – 5.5 kA.
• Solid State Trip – Controlled by microprocessor. Setting is
accurate with high precision device. It is suitable to use when
there are various protection devices also needs to be protected.
• Motor Protection – Suitable it be used for motor starter, delta
and star connections, and inverter. Handles in rush current up
to 600% of full load current and enable starting time up to 3
seconds.
22. RESIDUAL CURRENT CIRCUIT BREAKER
(RCCB)
• Purpose: Instead of protecting electrical devices, it protects human bodies
from getting electrocuted.
• Rating of load current – up to 63 A.
• Residual current ratings – 30mA, 100mA, 300mA.
• Trip testing can be performed by pressing blue button as shown in slide 6.
23. BASIC WORKING
PRINCIPLE
• Assume RCCB placed across live and
neutral wire.
• If the current in live wire (L-L) and neutral
wire(N-N) are not equal, RCCB placed
across live and neutral wire will trip as
shown in figure below.
• The difference between current in live wire
and neutral wire is known as residual
current.
• In the next section, we will look how it
protects human bodies and what causes the
building up of residual currents.
25. • Initially current of 10 A flows through live
wire
• Current of 10.1 A flows through live wire
when he/she touches live wire.
• Therefore residual current of 0.1 A will flow
through him/her to the earth and returning
will be only 10 A through neutral wire.
• This residual current is detected by RCCB
and automatically switch will trip.
• Hence saving the person from getting
electrocuted.
26. DETAIL WORKING PRINCIPLE OF RCCB
Current transformer is used to magnetize the coil present inside
RCCB.
When there is no residual current, there will be no flux in the
iron core of CT. Hence, no current will be induced in secondary
coil.
So when load is placed across resistor between live and ground,
there will be current drawn by it (𝐼 𝑅).
Therefore there will be residual current that will generate flux in
CT coil.
Then, secondary coil will be induced. This will cause
electromagnetic coil (EM coil) to magnetize and eventually
causes the switches to trip.
27. TYPES OF RCCB
2 – pole: used for single phase
supply that involves only live and
neutral wires.
4 – pole: used for three phase
supply that involves red, yellow,
blue and neutral wires.
29. MCB MCCB RCCB
Current Rating Up to 63 A. Up to 1000A. (100A
is commonly used)
Load current: 63 A.
Residual current: 30mA,
100mA and 300mA.
Cost Less Very High High
Size Small Big Small
Manual ON/OFF Yes Yes Yes
Trip level Fixed Variable Fixed
Earth fault protection No No Yes
Overload protection Yes Yes No
30. MCB MCCB RCCB
Electrical Shock Protection No No Yes
Number of poles 1, 2, 3 and 4 2, 3 and 4 2 poles – single phase
4 – poles – three phase
Interrupting Capacity Up to 10kA Up to 10 – 100kA -
Under voltage trip - Yes -
Shunt trip - Yes -
Auxiliary alarm - Yes -
Uses Homes
Commercial
Industrial
Commercial
Industrial
Homes
Commercial
Industrial
31. REFERENCES
Electrical Engineering Centre. 2018. Types of Molded Case Circuit
Breaker MCCB - Electrical Engineering Centre. [ONLINE] Available
at: https://www.electricneutron.com/circuit-breaker/types-of-molded-
case-circuit-breaker-mccb/. [Accessed 02 February 2018].
Electrical engineering Community. 2018. Residual Current Circuit
Breaker (RCCB). [ONLINE] Available at: http://engineering.electrical-
equipment.org/electrical-distribution/residual-current-circuit-breaker-
rccb.html. [Accessed 02 February 2018].
YouTube. 2018. (English) Electrical, Electronics by G K Agrawal -
YouTube. [ONLINE] Available
at: https://www.youtube.com/playlist?list=PLMemYhKF_WNXSNZG9-
FauJdN4RDidutfd. [Accessed 02 February 2018].
