Day 24: MCCB - Moulded Case Circuit Breaker

For today.. i have a task which needs me to understand the operation of the MCCB. Hurmm... What is MCCB?

MCCB stands for Moulded Case Circuit Breaker. It is commonly used in designing the Switchgear, UPS, MCC and etc.. In my understanding, the MCCB is a device which we used to protect our electrical equipment from being burn due to overload current or lightning. It works by  isolating the circuit either because we want the power off or to isolate because there is a fault. It use trip units which monitor the current flowing through the breaker and trip when it gets too high.

Hence, It is one of the obligatory device to be installed in the design for the vital protections.

                                   Example of the Breaker                Maintenance of the breaker

Previously during the FAT, i reckon that almost 70% of the manufactured design was installed with the breaker. There are many types of breaker actually..

i)   VCB    - Vacuum Circuit Breaker

ii)  Oil CB  - Oil Circuit Breaker

iii) Air CB  - Air Circuit Breaker...etc

Operation

The circuit breaker must detect a fault condition; in low-voltage circuit breakers this is usually done within the breaker enclosure. Circuit breakers for large currents or high voltages are usually arranged with pilot devices to sense a fault current and to operate the trip opening mechanism. The trip solenoid that releases the latch is usually energized by a separate battery, although some high-voltage circuit breakers are self-contained with current transformers, protection relays, and an internal control power source.

Once a fault is detected, contacts within the circuit breaker must open to interrupt the circuit; some mechanically-stored energy (using something such as springs or compressed air) contained within the breaker is used to separate the contacts, although some of the energy required may be obtained from the fault current itself. Small circuit breakers may be manually operated; larger units have solenoids to trip the mechanism, and electric motors to restore energy to the springs.

The circuit breaker contacts must carry the load current without excessive heating, and must also withstand the heat of the arc produced when interrupting the circuit. Contacts are made of copper or copper alloys, silver alloys, and other materials. Service life of the contacts is limited by the erosion due to interrupting the arc. Miniature and molded case circuit breakers are usually discarded when the contacts are worn, but power circuit breakers and high-voltage circuit breakers have replaceable contacts.

When a current is interrupted, an arc is generated. This arc must be contained, cooled, and extinguished in a controlled way, so that the gap between the contacts can again withstand the voltage in the circuit. Different circuit breakers use vacuum, air, insulating gas, or oil as the medium in which the arc forms. 

So..... How is it? get any idea bout circuit breaker? Actually we also could see MCCB in our home. The current terminal detector, which normally located high attached to our walls, was built by combining the circuit breakers. 

residential common usage

 ha...... so we always see it.. but now only i know what the device we called during this practical sessions... hahahahahahaah....

Day 23: FAT Report..

Today maybe differs from my previous days in TFDD PGB...WHY?? coz i still feel fresh and revive from previous FAT sessions which helps me a lot in understanding the engineering phase especially in the technical work.

Those engineers, technicians and sales persons involved in yesterday's FAT session, leads me to the new phase@era of my mindset ...widen my knowledges and also boost my morality in gaining knowledge as much as i can during this 3 months period. What i could see, the professionalism credibility shown by all of the respective persons such as, in house engineers, sales person, manufacturer  are extremely enormous. They actually polished my inner sides and take them as my models in improving my way of life.. How they conduct meeting with their high level of confidence and very clear explanation regarding this project also open my eyes and yet still fluctuates inside my brain.

Hurmmm... i'm 100%ly sure, it could be difference if they are in the gov sectors. It is what we should learn and improve in order to bring our gov management to the top satisfaction, efficient and be professionals in doing our work... That's WHAT I'M GOING TO BE!! i will ensure that i could achieve the same confidence level and professionalism in my way to be an engineer.

For today's work, i need to sketch or actually type a report due to yesterday's FAT. With all the pictures and and informations that i captured, it is an easy task for me... I do really hope, i could be involved in this kind of agenda or activities again... Plus, They treat you an expensive meals as well....!! hahaha... But, im too shy to show my passions towards FOODs..!!

Day 22: FAT at Swift Energy Shah Alam (part II)

Since FAT is a must procedure for each project design, it has to follow certain procedures for easier interpretation and also brief overviews by the manufacturer in order to comply the demanded specifications.

As i told previously, there 2 FATs have been conducted at the SWift Energy Sdn Bhd. The 2nd project is a Dual DC charger. This project is actually for the TANJUNG LANGSAT CITY GATE STATION as the end user. Swift energy have been awarded to build/construct the needed charger to be installed for the latter project.

How PETRONAS choose certain developer/manufacturer company in their project development...hurmm.. is something that i'm not well aware of.. But i believed, they open bidding session for those interested company & choose the best one.... i guessed...hehehhe

                                         The Dual Charger Rack   

                                                                                 

The Manufacturer personnel testing the equipment

The Pictures above demostrates how they do the FATs. Witnessess by the end user (PETRONAS), and customer (Misi Setia Oil) personnels, the test have been conducted manually until all the equipment (circuit + rack + design specification + function evaluation) being tested. Prior to this procedure, the manufacturer would have to provide and well-ready for all the questions being thrown by the customers@end user. It is to prove that the manufactured design comply with the specs.

Soon as the FAT take place, the committee members will have a thorough discussions. This will enclose all the unsatisfactorily facts, changes, and alterations outer from the customers and end user in order to meets their expectations. This process could be considered the final process since it determines whether the manufactured designs being accepted or not.  So, in other words, the manufacturer needs to re-manufactured or slightly change their designs as needed.. In other perspectives, if the manufacturer doesn't follow the specification given, they gonna bear all the losses and have to re-built the designs.... hurmmm what a waste....

Day 21: FAT at Swift Energy Shah Alam

Hallo... As i told last week.. today i have been invited by Mr. Adli in FAT checking. FAT is Factory Acceptance Tests. FAT is conducted to determine and document the equipment hardware and software operates according to its specification (as per demanded by the customer), covering functional, fault management, communications, support systems and interface requirements. The FAT demonstrates that the hardware and/or software work according to the specification. It is particularly important for highly integrated systems due to the complexity of the potential problems that could occur. For programmable systems, the FAT demonstrate that the application program satisfies the requirements of the software specification and works within specified hardware. 

Enough with the definition... now its time for me to share my experience there.....

I rushed from home, shooting to Shah Alam.. by 100% depending on the Map given by Mr. Adli, i drove to Shah Alam, seksyen 16.. Hurm... afraid of the consequences of lateness cause me to start my journey at 7 a.m.. Serious, driving to S.Alam by yourself could cause you to end up circling the roundabout thousand times. I end up, asking people by the roadsides for help. After those hassles, i arrived at the factory compound around 8:15 a.m. Darn!! im afraid that im late already since the meeting gonna starts at 8 a.m....

Once arrived, there are several questions like bubbles keep floating in my mind. AM I AT THE CORRECT PLACE??   NO one here yet... is it i'm too early... ?? i dont think so... it this the place? Why it looks like a stranded bulding?.. hurmm... i managed to get hold of a young guy whose wearing so called an uniform... According to him, he forgot to bring the company key and waiting for his colleague to open it up. Out of no where, i saw Syahirah driving thru the alley in her brand new Honda.. At last!! feel so relieved.....

Ms Syahirah is a junior engineer in the EMD department... So, I'm at the correct place and the FAT will be held at SWIFT POWER ENGINEERING SDN BHD.

The meeting starts soon after all respective person arrived at the Company. The FAT  involved the end user ( Petronas), customer (  Misi Setia and Tanjung langsat City Gate) and the developer and contractor (Swift Energy) representative. Conducted by Mr Adli, the meeting starts with the project overview in order to give brief explanation particular point that needs to be check in this FAT sessions. There are 2 projects will undergo this FAT session. The FAT, begins with the MISI SETIA OIL GAS 

In this project, Misi Setia Oil Gas Sdn Bhd, required a single charger (battery) UPS system for their current project. Since, Petronas Gas Berhad, is the gas supplier to this company, PGB also needs to monitor whether the designed UPS system specifications meets the PTS (Petronas Technical Standards) recommendations in order to maintain the equipments at both ends. 

  

Single DC Charger FAT checking

Under this DC charger FAT check, the inspection could be divide into 3 parts which are :

i) Visual Inspection

ii) Electrical Inspection

iii) Functional and Load Test

Visual Inspection

During the visual inspection session, the dimensions of the object (DC UPS) is being measured. This measurement should comply with the approved GA drawing.

The external layout/presentation such as the arrangement and allignment of the meters/LEDs/labels/ switches also will be compare with the approved GA drawing.

Electrical Inspection

For Electrical Inspection, every component arrangement was manually checked according to the given SLD (Single Line Diagram). Each connections should comply with the SLD as agreed by the involved party. Electrical checking is very critical and crucial because failure to do so could lead the consumer to buy unreliable equipments. This inspection involve the input voltage (Vac), Frequency, Boost Voltage (Vdc), Float Voltage (Vdc), LEd indication and etc.

Functional and Load Test

In addition, The electrical inspection is then proceed to the functional and load test. The results prior to this test will determine whether the equipment is well functioning or maybe need some changes in order to comply with the PTS and consumer demand.

HUrm...!! What do you think?? interesting Rite? we'll continue on the next post... 

Day 20th : Labour Day Replacement

Today...is holiday hehehehe...

On 30th April 2010, is a replacement public holiday due to Labour Day Celebration which is actually tomorrow..1st May 2010... Hurmm... since i am also an employee, i guess i should reward myself too..... hahahha... so, im thinking to go for Pesta Mencandat Sotong at Terengganu... hihihihihi... Anyway, nothing to write today.. see you on Monday.... This coming Monday (3rd May 2010) is gonna be an interesting day since i was invited to join Mr Adli in FAT.. hehehehe.. what is FAT?? wait till Monday... :) C ya...

Day 19: My 1st Technical Meeting

Today, i rushed out from house coz i want to drop by the Nasi Lemak stalls. I have been monitoring this stall since my 1st day working. HAHAHA.. it sounds like a terrible stalker...but.. i only peep on Nasi Lemak okkk...
So, once i parked my car, i shoot to buy NASI LEMAK KERANG... Darn!! it cost me RM2.90.. Normally, if i buy at the pantry, it will only cost me RM 2.50..

HAHAHA..maybe the deficit is low, but with that 40cents i could use for my train fares. I quickly hopped in the LRT after that.huhuuh... seats are fully occupied.. hurmmm, need to be earlier i guess.

Once Arrived, as per normal, plugged in my laptop, and went to the pantry for breakfast. huh!! nothing special about the nasi lemak.. just ordinary taste.. A little chit chat with the staffs, starts my day with a laughs and smiles. Hurmm... what a way to start my day....

Ok.. back to the topic, I was invited by Mr Tuan Azizi to join him in a RCA meeting. Mr Tuan Azizi post as a Senior Engineer in Electrical department. RCA stands for Root Cause Analysis. It is a meeting where all the engineering team will gather and discuss to overcome any problem occurs in their project. Normally, RCA is a post-project meeting to clarify their problems after a project have been settled. It usually involves the faulty, ignorance and carelessness of the project individuals who cause the project to be in losses or failure.

In this meeting, Mr Tuan Azizi used some methods to narrow down the bigger scope of failure in order to investigate and find the respective reason causes the VO (Variation Order). Variation order is specificiation of equipment which need to be installed or improved the designed project due to the consumers demand. VO is actually some sort of losses to the company since they need to reconstruct the already design project. This could lead the company to pump in more money just to improved it since the engineer lack to acknowledge the consumers demand. In this case, simple mistake or overlooked could cost them HUNDREDS MILLION RINGGIT.,..!!!

Method that have been used are :-
1) Fish Bone
2) 5 Why methods.

From this meeting, i could learn that as an engineer we have to be more responsible and high disciplines. This mentality could prevent the engineer to do silly mistakes which cause the company to be losses. Engineers, have to be prepared in any circumstances raised on the project. Yes we cant forecast the future, but could prepare the way to prevent any unwanted or undesirable situation especially involving the losses of the company and most important,if it involves human life.

Day 18: Function of UPS components (Con't)

Each Components in the UPS system have their own roles. The components allocate inside the system are :

1. Rectifier
2. Inverter
3. Battery
4. Bypass Transformer
5. Maintenance Bypass

There are several categories of static UPS system  available. Broadly speaking,UPS modules fall within one of three operational design architectures, namely off-line, line interactive and online.

However, irrespective of their individual design criteria features are common to all forms of static UPS systems - i.e.. they all contain batteries which stores energy when the mains supply is available and a means of converting the battery charge into an alternating current (ac) supply in times of mains failure. All systems must therefore include a battery charger and a power inverter circuit.

As described above, the battery provides a power source for the inverter when the mains supply fails, whereupon it discharges at a rate determined by the critical load connected to the UPS output. The inverter automatically shuts down when its DC supply falls below a certain voltage, therefore the duration for which the critical load can be supported in times of mains failure depends upon the battery capacity and percentage applied load.

What happens if the UPS fails?

A UPS Fault is generally seen as the inability of the inverter to provide the correct voltage or frequency at the UPS output terminals and the resulting actions that take place may vary between models. Usually, the UPS control logic will detect the failing output voltage /frequency as the load to the bypass line in a make-before-break-fashions. However, If the inverter is not synchronized to the bypass supply when the transfer is called from, it will be impossible to perform a break-free transfer operation, consequently there will be a brief supply break while the transfer takes place.

Hurm.... actually the UPS is like a mandatory usage of the organizations@firm in order to maintain their productions. Since it is well usage in industries especially O&G, UPS became frequently updated and improvised in order to meet the specifications needed by the consumers.....