Electricity is an "impersonal existence".

Impersonal' means one that does not belong to any side, nobody is his friend and nobody is his enemy. The universe has no friends and enemies, because the so-called enemies are inside it only and the friends are also inside; so, to whom does it belong?

It can cook your food, heat your stove and move the railway train, but it can also destroy life.

Di basta-basta nginingitian ang kuryente. Sabi nga nila, kahit gaano katagal nagawa ang isang building, in split seconds na may nangyaring electrical fault at hindi naagapan, pwede sumabog at mawalan ng ari-arian, and worse, pwedeng bumawi ng buhay.


Causes of Fire:
1. fixed wiring 34.7%
2. cords at mga plugs 17.2%
3. light fixtures 12.4%
4. switches, receptacles and outlets 11.4%
5. lamps and light bulbs 8.3%
6. fuses at maging ang mga circut brakers 5.6%
7. metro at meter boxes 2.2%
8. mga transformers 1.0%
9. unclassiified o di nakikilang mga distribution equipments 7.3%

Safety measures should always be at-the-top-of-the-list priority. After all, prevention is always better
than anything else!

Automatic transfer Switch, time delay???

EMERGENCY!

Dalawang supply sa ATS, isa galing sa utility company, isa galing sa generator para sa emergency power supply.

In case of any undervoltage, overvoltage, loss of phase, or total power failure, ang generator ay gagana after a PRESET TIME DELAY.

Then once na nastabilize ang generator voltage, that's the only time na ang UTILITY ACB ay mag-oopen o madidisconnect, at ang GENERATOR ACB ay magcloclose.


NORMAL...

When the utiility power returns, the utility ACB will IMMEDIATELY BE CLOSED.

However, in this case, hindi agad-agad magdidisconnect ang generator.

Magkakasabay pa din sila.. parehong aandar ang dalawang ACB and after a preset time delay (after magcool down ang generator), that's the only time that the GENERATOR ACB will be OPENED and disconnected again.

Measuring Instruments in the Panelboard

1. Frequency Meter

Ø Measures on how many times an event occur. This frequency meter is usually refrred to as counter. Frequency meter is connected in series with the generators. A problem also with the use of an frequency meter is the need for the meter to be inserted into the circuit and become part of it.

Warning: Mistakenly placing it in parallel with a circuit will blow the fuse, possibly damaging the meter and causing injury. In AC circuits, a current transformer converts the magnetic field around a conductor into a small AC current.

2. kVAR meter

As its name implies, kVAR meter measures or present the amount of reactive power present in a circuit. As we all know, KW and KVAR are confusing.

It seems that usually, one thinks that if KVAR's in a system is equal to zero, then there is no power flowing. (maling mali po). This person fails to understand that real power and apparent power are not the same for a system operating with a no unity power factor. This apparent power is simply circulating power due to the phase shift between the source and the loads. This additional power that appears to be flowing requires the equipment to be rated higher than that for a system operating at unity.

Obviously these circulating currents are really producing no useful work. It is the job of the EE or the power plant operator to correct the load reactance as close as possible to unity to increase efficiency and reduce operational costs. Thus, kVAR meter is very much helpful in the power plant.

3. Kilowatt Meter

Ø The kilowatt-hour meter is designed to reliably, and accurately measure the electrical energy (kWh) used in your home or place of business.

Ø When you look at the face of a kilowatt-hour meter, across the middle you will see a metal horizontal disc that turns when energy is being used. This disc is designed to turn like a motor wheel when energy passes through the meter, and it is calibrated so that one rotation of the disc corresponds to a specific number of kilowatt-hours. This means that depending on the meter make or type, one meter may spin twice as fast as another to register the same kilowatt-hours.

Ø The kilowatt meter and kilovolt-ampere meter measure the power (demand) delivered to the facility being metered averaged over a short duration of time. These facilities are larger users of power than residential or small commercial energy use

4. Synchroscope

Ø A synchroscope indicates when two AC generators are in the correct phase relation for connecting in parallel and shows whether the incoming generator is running faster or slower than the on-line generator. The synchroscope consists of a two-phase stator. The two stator windings are at right angles to one another, and by means of a phase-splitting network, the current in one phase leads the current of the other phase by 90°, thereby generating a rotating magnetic field.

Ø The stator windings are connected to the incoming generator, and a polarizing coil is connected to the running generator. The rotating element is unrestrained and is free to rotate through 360°. It consists of two iron vanes mounted in opposite directions on a shaft, one at the top and one at the bottom, and magnetized by the polarizing coil.

Ø If the frequencies of the incoming and running generators are different, the synchroscope will rotate at a speed corresponding to the difference. It is designed so that if incoming frequency is higher than running frequency, it will rotate in the clockwise direction; if incoming frequency is less than running frequency, it will rotate in the counterclockwise direction. When the synchroscope indicates 0^o phase difference, the pointer is at the "12 o’clock" position and the two AC generators are in phase.

Variac

http://www.answers.com/topic/autotransformer

Electrical Appliances in flood

Readiness, Response and Recovery.

Emergency 101

Before entering a home after a flood, be sure that the electricity has been
completely shut off at the panel. If you are not certain how this is done, get a licensed electrician or authorized service person to do this for
you.

Pag meron pa ding tubig sa paligid ng appliances, iwasang pumunta malapit dito lalo na't di sigurado kung nakashut off ang appliances. Pweding masave ang appliances pero kailangan munang PATUYUIN ang mga ito bago gumawa ng hakbang.

SAFETY MEASURE:

NEVER allow the connection between the machine's power cord and the extension cord to lie in water.
ELECTRIC CIRCUIT BREAKERS AND FUSES can malfunction when water and silt get inside. Discard ALL circuit breakers and fuses that have been submerged.



Appliances in flood can be classified into two:
a) submerged in water
b) just wet by rainwater

Appliances submerged in water are often NOT REPAIRABLE but the appliances that have been saved and not flooded are often REPAIRABLE.

Water, especially dirty floodwater, na puno ng putik, causes many problems (lalo na pag nakapasok ang mga ito sa motor windings, electrical contacts at mga switches). Pwedeng kalawangin ang mga ito at di na gumana.

Kung nakapasok naman ang mga ito sa insulation, ang mga appliances na mga heater o cooler gaya ng electrical ranges, freezers or ref ay pwedeng di na rin gumana nang maayos at magkaroon ng masangsang na amoy.

Appliances damaged by water can sometimes be made functional, but they will likely have a shortened life expectancy. Depende kung gaano katagal ang mga appliances bago sila nabasa, ang buhay ng mga appliances ay umiikli..

1) How to CLEAN APPLIANCES

Never hose them down!! Ang mga appliances ay di gamitan ng hose ng tubig para malinis kaagad. Keep in mind that electricity and water should not mix..

Pwedeng gumamit nalang ng basang pamunas na madaling matuyo para alisin ang dumi sa appliances. Pwede ding gumamit ng electric fan to increase airflow.

You can also try using CONTACT CLEANER ( solvent na iniispray at madaling mag-evaporate gaya ng isoprophyl alcohol ) para sa mga contacts ng switches.


2) GETTING RID OF ODOR

If an odor persists, wash with a solution
All we need are the following:
isang kutsarita ng baking soda
isang 1/4 gallon ng tubig
isang cup ng suka

Pwede ding isang cup ng household ammonia kada isang galon ng tubig.

Ondoy!!!

Sept 29, 2006 - "The biggest floods in decades threatened Vietnam's central provinces on Wednesday following a powerful typhoon that swept into the country.

Typhoon Ketsana slammed into Vietnam late on Tuesday dumping torrential rain across central Vietnam that left 294,000 homes destroyed, damaged or submerged by floods. Around 357,000 people in 10 provinces were evacuated."

FYI, ang bagyo ay nagpalit lang ng pangalan pero ito pa din ang bagyong nagdulot ng takot at kawalan dito sa Pilipinas. Ondoy?!! Well, sya na nga. Date dito sa Pilipinas? Sept. 26, 2009.



It's not often, or let's say, very UNUSUAL to get flooded in 25 provinces in just 12 hours, na karamihan ay lampas-tao pa ang baha. It actually made most of the hometowns here in Luzon almost an OCEAN. =(

And the most common set-up sa mga naapektuhan: no food, no vehicle, no water, and NO ELECTRICITY.

Due to massive flooding, the Manila Electric Co. cut off power last Saturday in some areas of its franchise to ensure the safety and protection of residents.

Kasama sa mga nawalan ng kuryente ay Malabon, Quezon City, Rizal, Marikina, Makati, Las Piñas, Taguig, Manila, Taytay, Cardona, Morong, Cainta and Teresa Rizal.

Nine substations were actually affected by the massive flood.

POWER LINES

Ang ilang mga tao ay nakakapit na sa POWER LINES na nasa matataas na poste para lang makatawid sa baha. Buti na lang at alang kuryente. Kung meron, ay napakadelikado nito.

Ang broken power line kasi na nakasadsad sa ground ay nagdadala ng napakataas na boltahe. Kailangan nating lumayo ng AT LEAST 10 METERS pag makakita ng ganito para maiwasang makuryente.

What more sa baha, kung saan ang tubig ay napakalapit dito. Water is a very good conductor of electricity thus it's very hazardous to let electricity pass through the power lines in a flood so close to them. Buti na lang at listo din ang MERALCO.

However, it was also a very uneasy feeling na malamang kinailangan pang kumapit ng mga tao kahit sa kable ng kuryente dahil sa napakataas na baha..

That's how powerful Ondoy was!!


APPLIANCES:

Warning: Do not use electrical appliances that have been wet. Water can damage the motors in electrical appliances, such as furnaces, freezers, refrigerators, washing machines, and dryers.


Conclusion: It seems that God reminds us about our shortcomings.

Earth Leakage Circuit Breakers

Ang earth leakage circuit breaker ay ginagamit bilang proteksyon ng motor o ng tao sa residual current.

Pag nagkakaroon ng unbalance current sa hot wire at sa neutral wire (balance fault), magtritrip ang ELCB para madeenergize agad ang electrical circuit.

Maaari kasing tumalon o nagleak ang kuryente sa ground o sa ibang eletrical circuit na pwedeng makasanhi ng eletricution o sunog.

Take note na ang kuryente ay nasa isang loop lang. Ang hot wire ay naghahatid ng kuryente sa load samantalang ang neutral ay nagdadala ng return current na sya ring parehong pumapasok sa load. INPUT CURRENT = OUTPUT CURRENT principle. Ang ELCB ngayon ang magbabantay sa balanse ng line side at neutral.

An insulation deterioration due to aging of regular insulation of equipments or wiring can cause low value regular leakage current (of the range of milliamps to few amps) which cannot be detected by over current relay or earth fault relay. But these currents can cause fatal accidents resulting to burning to loss of life to people working around and also results in regular energy loss. Pwede ding faulty wiring o maling paggamit ng device kaya nagkakaroon ng EARTH LEAKAGE o RESIDUAL CURRENT.

Ang ELCB ay tinatawag ding risidual current circuit protetion. =)

Related link:
http://www.standardelectricals.com/pdf/RCCB_new.pdf

Frequently asked questions, powerline!!

1) Are power lines insulated?

Kala ng karamihan sa atin, ang power lines o yung malalaking kable na galing sa utility company papunta sa mga poste papunta sa mga consumers have INSULATION MATERIAL around them kagaya ng mga electric cords ng mga applicances.

FYI, ang high voltage na linya ay HINDI INSULATED. The protective covering around it is not an insulation. It only PROTECTS THE LINE FROM WEATHER CHANGES.


Ang mga appliances natin ay gumagamit ng 110 o 220 Volts.
At that level, insulation material is practical. But at 7,200 Volts o higit pa, ang insulation material ay masusunog lang dahil di nito kakayanin ang mataas na kuryente, right??

And if the material was substantial enough to handle the HIGH VOLTAGE, it would be too expensive, TOO THICK and TOO HEAVY to USE.

2) Why can birds sit on power lines without being hurt, when it would kill me to touch that same line?


Ang kuryente daw ay tamad, By nature, hinahanap ng kuryente ang PINAKAMADALING PATH papunta sa ground.

When a bird lands on the line, her body becomes charged--for the moment, it's at the same voltage as the wire.

Kaya lang, di sya makukuryente kasi mas pipiliin ng current na dumiretso na lang sa copper wire ng power line kaysa pumasok o mag-detour sa katawan ng ibon na less yung conductivity.

Makukuryente lang ang isang ibon KUNG ang isang paa nya ay nasa conductor at ang ISA ay nasa isang path to ground.

Kaya kung ang isang squirrel ang dumaan sa power line, makakasurvive sya PERO makurkuryente din the moment na mahawakan o maapakan nya ang (grounded) transformer na nasa dulo ng wire.


Ngayon, if in any case, ang isang tao ay umakyat sa puno at humawak sa power line, madaling makakapasok ang kuryente sa kanya, papunta sa puno, papunta sa ground.
=S

Sa contacts lang ang diskarte nyan. hehe

Contacts

Well, there are terms that may be confusing for young electrical students at para na din sa ibang tao. I mean, like in switches, my mga terms na technical na pag narinig pa lang ay ganito kaagad ang masasabi: "?gh?anfls?".

Isa na rito ang switch configuration. Ano ba ang single-pole single throw, double pole double throw, four pole double throw, at paano mo masasabi kung ang isang switch ay ganyan o ganito?

The definition lies on the two important KEY WORDS. POLE and THROW.

Ang dalawang salita na yan ay tungkol sa switch contact variations.

A "pole" is a set of contacts and terminal para sa ISANG CIRCUIT.

Ang salitang "throw" naman ay para sa iba't ibang posibleng posisyon na pwede sa switch.

For example, a single throw switch has one position that closes a contact, at ang double -throw has two positions, kagaya ng "make-before-break" mechanism ng relay, and so on. ;)

1) SINGLE POLE-SINGLE THROW:

Ang pinakasimpleng on-off switch: The two terminals are either connected together or not connected to anything. An example is a light switch.

American wiring name: two-way switch

2) SINGLE POLE DOUBLE THROW

A simple changeover switch: C (COM, Common) terminal na pwede maconnect sa L1 o sa L2. Pag nakadeenergize ang switch ay magkadikit ang common at L1 pero pag naenergize ito ay lilipat ang common at didikit sa L2.

Double throw kasi DALAWA ang pwedeng posisyon ng switch. Magpapalipat lipat lang ang common sa line 1 at sa line 2.

American wiring name: three way switch

3) DOUBLE POLE SINGLE THROW
Take note na dalawang single pole single throw lang sya na kinokontrol ng isang mechanism. Pag nakaopen yung isa, ganun din sa pangalawa.
At pag nakaclose contact ang isa, ganun din ang isa.


American wiring name: double pole switch

4) DOUBLE POLE DOUBLE THROW

Ito'y dalawang SPDT switches controlled by a single mechanism.
A is connected to B and D to E, or A is connected to C and D to F. ;)




Conclusion:
Switches with larger numbers of poles or throws can be described by replacing the "S" or "D" with a number or in some cases the letter "T" (for "triple"). In the rest of this article the terms SPST, SPDT ;)

Related link:
www.tpub.com/.../neets/14175/css/14175_209.html

Malay sa relay na yan. =( A BIG NO NO. (part 3)

Anong mangyayari pag naconnect ang isang AC relay sa DC?

Ang isang AC relay coil has both inductance and resistance limiting the current.
Generally, ang AC relay ay nakadesign nang may mas mataas ng current kesa sa DC
(kasi mas less efficient ang AC). Pag naikabit ito sa DC at hindi sa AC, magkakaroon ng mas
mataas na current pa rin. The relay would operate properly (for a while) but would eventually
fail due to the coil overheating. Depending on ambient temperature and the specific relay,
failure could occur in minutes, or might take years.

Malay sa relay na yan. =( A BIG NO NO. (part 2)

We can say that a relay is A SPECIAL KIND of switch.

Here are two examples kung bakit kailangan natin ng relay.


On the upper part is a diagram for automobile circuit.

Pag naka-on ang ignition key ng sasakyan, it allows electricity to flow to the starter solenoid ( yun ang relay) which then connects the battery to the starter motor.

So why do we need the "middle man" relay? Pwede ba nating e-eliminate na lang ito at iconnect ang ignition wires sa +battery terminal at yung isang wire sa motor starter naman?

The important point here is that the electromagmet is using a small amount of current to control a large amount of current to the starter motor. (Remember that the electromagnet and the switch are NOT connected electrically).

Have you noticed that all of the wires (except the ignition wires) are purposely drawn with thick lines? That's because some circuits (like the starter) require tremendous amount of current. (kaya kailangan din ng mas malaking kable).

(If you look at an automobile's battery cables, you will notice they are quite thick.)

Pag maliliit na wire ang ginamit natin, di nito kakayanin ng insulation nya ang mataas na current, kaya masusunog ito, at uusok.

We do have a second choice. Pwede tayong gumamit ng malalaking kable mula sa battery gamit
ang heavy duty ignition switch. However, do you think it would be easy to squeeze cables into the steering column and squeeze in a heavy duty switch too?

BURGLAR ALARM SYSTEM

Referring to the diagram, let's trace the electrical flow.

Kung makikita nyo, mula pt. V2, pupunta sa "C". Mula sa negative battery terminal, pupunta sa V1, tapos sa V2, at dahil tuloy tuloy ang alarm loop, pupunta sa "C" at pagkatapos ay sa positive battery terminal na. Sa circuit loop na 'to, dadaloy ang current sa electromagnet causing the common terminal to switch contact mula "C" patungo sa "B" At dahil walang contact sa A, the siren will not make any SOUND.

Pwedeng lagyan ng isa o mas maraming magnetic switch in series sa alarm loop para magkaroon ng warning signal o alarm sound. Kaya lang, ang mangyayari dito, tuloy-tuloy nga ang kuryente mula pt "C" to pt. "A" hanggang sa siren, NGUNIT HINDI sa electromagnet.

Alarm Circuit 1 does suffer from one serious flaw. Can you see what it is? Pag nareconnect ulit ang alarm loop, madidisconnect lang ang siren. This is a VERY IMPRACTICAL WAY AND NOT RECOMMENDED TO ANY ALARM SYSTEM. The siren goes off! Kung nabuksan ng isang magnanakaw ang pintong me magnetic switch nang pwersahan, sasarhan lang nito ulit ang pinto at di na tutunog ang siren.


Para maging efficient sa tao, kinakailangan natin ng isang device na pagproprovide ng additional contacts na mag-aallow ng isang circuit na gumana habang ang isang circuit ay putol. At yun ang nagagawa ng transfer mechanism ng common contact ng isang relay. =)

Malay sa relay na yan. =( A BIG NO NO.

Lam mo ba kung ano ang relay? Bakit ginagamit ito at paano sya nakakatulong sa atin?
Well, it's time for electrical wareness na rin.

Ang relay ay isang simpleng electromechanical switch na binubuo ng electromagnet at mga contacts.

There are three important functions of a relay:
1) A relay provides isolation from one electrical circuit to another.
2) A small coil voltage can control a large load. This is usually how computers control the outside world. (gamit ang relay, hmmn)
3) A high control voltage can control a low load.

Nosebleeding ba? Well, let me explain further. ;)
Ang relay ay pwede nating maconsider as an ELECTRICAL AMPLIFIER. Paano ba? As an amplifier, ang relay ay isang device na gumagamit ng maliit na electrical energy para macontrol ang malaking amount ng energy. Kung paano kailangan lang ng isang relay ng 24 V para makakakontrol ng 220 V ay isa sa mga unique qualities nito.

Or for example, you might want the electromagnet to energize using 5 volts and 50 milliamps (250 milliwatts), while the armature can support 120V AC at 2 amps (240 watts).

Ngunit, datapuwat, at subalit, ang relay ay dependent sa ibang devices like pilot devices o mga sensors. It opens or closes a circuit UNDER THE CONTROL of another electrical circuit. Gumagamit sya ng electromagnetic force to open or close one or many sets of contacts.















Ang tatlong me itim na bilog ay switching contacts ng relay.

When the electromagnet coil is turned off, ang dalawang contacts sa taas ay magkadikit, thus called "normally close" contact.

When power is applied, ang gitnang bar ay bababa at didikit sa isa pang contact. This opens the "normally closed" contact and closes the "normally open" contact.

Ito ang tinatawag na "make before break" contact na may dalawang contact para sa normally open at normally closed, at may common terminal. ;)

A relay actually consists of two separate and completely independent circuits.
The first drives the electromagnet. Pag nagkaroon ng power supply, ang first circuit (internal circuit) ang bubuhay sa electromagnet na nasa relay. Ang electromagnet na to ang magaattract ng armature para maenergize ang second circuit. Yun na ang papunta sa load.


Ang picture sa taas ay nagpapakita ng isang napakasimpleng relay.

The coil is attached to the bottom two lugs. Ang dalawang pinakababa na rin ang ikakabit para sa power supply.

Ang nasa taas naman ay ang normally open at normally close na contact na meron common terminal sa gitna.


Pwede lagyan ng wire directly sa lugs, o ilagay sa isang socket.

Ngayon, what are the important considerations when choosing a relay?
Tatlo lang po.

1) coil voltage - This indicates how much voltage (AC or DC) ang kailangang isupply para maactivate ang relay. Ito yung parang input voltage ng relay. Take note lang po na hindi puwede magsupply ng mas mataas na voltage sa isang low voltage relay kasi masisira ito.

2) contact ratings -This indicates how heavy a load the relay can control. If you can't find exactly what you want, you can use a relay with a higher rating.

3) contact geometry - There are many kinds of switches, kaya marami din ang uri ng relay na babagay sa mga ito. The contact geometry indicates how many poles there are, and how they open and close.

Some examples are: single-pole single-throw; single-pole double-throw; and double-pole double-throw. Kung ala yung hinahanap mo ay pwede gumamit ng may mas maraming poles kasi pwede namang pabayaan ang mga unused contacts.

Ang relays ay karaniwang makikita sa ting mga bahay gaya ng mga appliances na merong eletronic control turning on something like a motor or a light. Pwede din siya sa mga sasakyan na gumagamit ng 12V supply voltage.

What is a motor control?

Ano ba ang motor control? A question that has no simple answer?? well, it is not.. however, mysterious, complicated subject that some people believe it to be.

As what the word control means, it governs or regulates. Pag sinasabing motor control, ang pinag-uusapan ay paano magmanage ng machines o motor, like starting and stopping, selecting forward or reverse rotation ng motor, limiting of the speed and motor protection.

Dalawa kasi ang klase ng MOTOR CONTROL: 1) manual para sa mga simpleng motor at (2) automatic para sa mas efficient at di masyado kailangan ng manpower na operation.

Sa basic na manual controller, ang pwede nating makita ay dalawang pushbuttons, isang START PUSHBUTTON at isang STOP PUSHBUTTON. Meron ding overload protection para maiwasang masira at magkaroon ng aksidente. I think ang pinakamagandang example dito ay ang welding machines. ;)

Ang automatic motor controller naman ay ginagamit para sa mabilisang produksyon, more accurate at more efficient na operations. Well kung mas mura magpakabit ng manual controllers, ang automatic system naman ay di hamak na nagiging mura pagdating sa flexibility, maintenance at operational costs.

Auxiliary Relays

Ang auxiliary relay ay parang isang PERSONAL ASSISTANT!!!

Ang auxiliary relay kasi gumagana IN RESPONSE to OPENING AND CLOSING of the circuit to ASSIST ANOTHER RELAY OR DEVICE in performing its function.

Kaya lang, ang auxiliary relay ay isang ALL-OR-NOTHING DEVICE din.

Here are some reasons kung bakit:

1) It can provide additional contacts pero di kayang magamit ng main relay.

2) It provides contacts of HIGHER RATING than those of the other relay, let's say measuring relay pero di din pwede. Ang auxialiry relay kasi ay DAPAT MAG-OPERATE sa mas mababang boltahe kesa sa operating voltage to cover variation sa circuit at sa relay itself.

3) It assist to perform a function over LONG CONDUCTORS, the resistance of which will NOT ALLOW THE MAIN OPERATING CURRENT TO FLOW from the starting point.

4) To insert DELAY in performing the function of the circuit.

Meron syang mga kayang gawin pero di rin pwedeng magamit.
Kaya it's the sense of BEING AN ADVANTAGE and IF NOT, ala din kwentang idagdag sa design..

POWER SYSTEM

Ang power distribution ngayon at ang mga control systems are far more complex kesa sa dati.

They are designed with MULTIPLE LEVEL of redundancy, na ginagamitan ng PLC, para sa back up at emergency at inputs para sa multiple building systems.

Una, ano nga ba ang PLC?

Ito’y isang digital computer used for automation of electromechanical assembly lines, amusement rides, or lighting fixtures. processes, such as control of machinery on factory

At ano ano ba ang mga pwede mangyari in case ng isang EMERGENCY or power outage sa distribution system????????

Well, pwede magkagulo!! Below is an example of how electricians react to emergencies. Pitong oras silang nagkaroon ng isyu sa kuryente na pwede sanang masugpo ng dalawampung minuto kung natrain lang ang mga electricians ng dapat nilang gawin.

10:30 A.M.

Biglang nawala ang kuryente.

Dahil merong anim na UTILITY LINES para sa facility, mula sa iba’t ibang substation, alang back up na generator na nakainstall. Napag-alaman ng facilities manager na APAT na circuit breaker ang open. Pano nangyari ito????

The MAIN TIE AUTO-TRANSFER SYSTEM is designed for open transition transfers. Ang mga relays ang nagsisilbing sensor para sa LINE VOLTAGE at nakikipagcommunicate sa ating PLC.

Ang PLC naman ang utak ng control system na nabubukas ng MAIN o ng BREAKER TIE para marestore ang service to the load.

Ang dalawang natitirang power source ay ang emergency lines na lang.

Step 1) Both services ay ginawang MANUAL MODE ng mga electrician in attempt na maclose yung mga ito manually. One at a time, the electricians tried to close them,pero nagtritrip agad ang mga ito. Ibig sabhin, me problema nga… tsk tsk.

10:50 A.M.

Step 2) A second attempt succeeds, and one main in each service is closed. Power is restored to part of the facility. Kaya lang, hindi nacloclose ang B main breaker. (So ito siguro ang me problema.)

Step 3) Having already closed the TIE at MAIN A, the electricians tried closing again B main breaker. Ang resulta, both the TIE BREAKER at ang B MAIN BREAKER ay nagtrip ulit at nagopen and circuit. The maintenance manager reclosed the B-main at this time, it REMAINED CLOSE. (whew! hehe)

Step 4)

With power partially restored, nagdecide ang maintenance crew na hayaan na lang muna ang power system at magpatulong sa iba. Dalawang contractor electrician na nag-install ng mga ito ang pumunta doon.

3:30 P.M.

Step 5) The contractor's electricians looked over schematic drawings for more than two hours. Kaya lang, narealize din nila na din nila kaya ang problema. Tinawagan nila ang Manufacturer mismo ng circuit breakers at sinabihan pupunatahn sila dalawang oras pagkatapos tumawag .

5:15 P.M.
The Square D Services representative arrives.

5:25 P.M.
All power is restored and production resumes.

In this distribution system, we have the HIGH VOLTAGE SWITCH na nagsusuply ng 13.8 kV
galing sa utility company. Pwede itong 150 ampere delta connected
power to two 2000 kVA
dry-type transformer.

At ano nga ba ang dry transformer????

Well, ganito yun.

Ang Dry-Type Transformers ay ginagamit sa
loob at labas ng isang building, eskwelahan, ospital,
commercial building at iba pang lugar na
nangangailangan ng dependable power supply.

Dry-Type Transformers are available for voltages
up through 34.5 kV (although the most common
upper limit is 15) and KVA ratings up through 10,000 (with 5000
as the usual limit). Ang dry type tranformer ay gumagamit ng hangin
para mapanaliting tuyo, lowering health and environmentally
concerns.

Ang dry type transformer naman ay connected sa MAIN TIE CIRCUIT BREAKERS.
Gamit ang PLC, nagkakaroon tayo ng automatic operation para makasigurong
magkakaroon pa rin ng kuryente ang BUONG SWITCHBOARD LOAD kahit ang
isang main supply ay mawalan.

Turbine generator? Parang nakita ba kita??? (o sun dial lang?!!)

I'm not a UP graduate, pero kung minsan pumapasyal pasyal na din ako dun dahil sa friends ko..

Nitong huli lang ay napagtripan naming maglibot libot sa UP diliman kasi holiday, alang pasok, national heroes day (August 21, 2009). Nag-enjoy naman din ako nang my nakita ako na malaking sculpture sa college of engineering na pinagawa ng mga UP ALUMNI. Isang malaking "U" na may malaking bar sa gitna.

Parang may arrow sa gitna ng arc, na di mawari kung ano. Well, sa picture sa kaliwa, putol ang semi circle na yun, kaya di mo masyado makikita. Una pumasok sa isip kin, yung U-shaped thing as a REPRESENTATION of a MAGNET, while the BAR-SHAPED na nakikita nyong nakasandal sa circle pointing sa U-shaped at parang "I" is an electromagnetic shaft. At ano ba yun???? hmmnnn...

Depicting the basic principle ng electricity, ang DALAWANG BAGAY na yun ay BUMUBUO NG ISANG TURBINE GENERATOR.


The diagram below shows how electricity is produced through ELECTRONAGNETISM.


Pero, dapat din pala, ang shaft ay napapalibutan ng COIL ng wire.


Ang magnet na merong DALAWANG POLES ay merong opposing magnetic force. Ang magnetic force na to ay nagpepenetrate sa coils making the shaft rotate. Ito ang dahilan bakit umiikot ang shaft. At sa tuwing umiikot ito, ang coil ang nagiging CONDUCTOR ng kuryente. Each section ng wire becomes a small, separate eletric conductor na unti unting nagkakaroon ng malaking CURRENT. Ito na ngayong ang nagiging ELECTRIC POWER na maaring magamit ng tao. ;)

Ngunit, datapwat, subalit, at pero, hehe, hindi naman din pala turbine generator yun, isa palang SUN DIAL na ginawa ng mga UP ALUMNI..=( well, ok na din yun.

Warning: "disconnected neutral"

Ang disconnected neutral at tinatawag ding open neutral fault condition. Ito'y nangyayari pag nadisconnect ang neutral wire sa main power supply


PERO nakakonekta pa rin ang hot wire sa panel at habang umaandar ang electrical loads, katakot takot din ang pwede mangyari sa ating mga appliances . Subukan mong gamitin ng test screwdriver na merong neon lamp sa neitral wire, ang lamp indicator ay iilaw pa parang live wire na din ang neutral wire. At bakit nagyayari ito???


Actually merong napakaliit na current na dumadaan sa neutral wire galing sa Live supply via the plugged-in appliance(s) to the Neutral wire.


If you unplug all appliances, lights and whatever else may be connected to the circuit, ang neutral wire ay ala na din current because there is no longer any path from it to the Live supply. Di din magtritrip ang circuit breaker kasi ang current na dumadaan mula sa live via sa ating mga load papunta sa neutral ay napakaliit para madetect ng ating circuit breaker.

A "Disconnected Neutral" fault condition ay NAPAKA UNSAFE kasi maaaring tayong maaksidente dito at makuryente while trying to find out why no appliances work samantalang nakaplug naman ito sa outlet.

FYI: Disconnected Neutral (Open neutral)" fault condition

Paano pag ang NEUTRAL WIRE ay energized pero hindi nagtritrip ang circuit breaker?

Ito'y nangyayari lamang KAPAG ang neutral wire ay hindi nakakabit sa main power supply samantalang ang Line or "hot wire" para sa curcuit are konektado pa rin sa panel, at ang mga appliances are nakaplug sa mga outlet.

Pag hindi konektado sa main supply, dadaaanan pa din ito ng kuryente sa twing umaandar ang mga electrical loads natin at dahil kailangan natural sa kuryente ang maghanap ng path to earth, delikado sa tao sa mahawakan ang neutral wire na tulad nito.


Walang ORDINARYONG circuit breaker sa OPEN NEUTRAL FAULT CONDITION ang magtrireip o MAGSHUSHUTDOWN kasi ang line-to-neutral na current ay HINDI GANUN KATAAS.

In that situation, if you put a voltage indicator, such as a test screwdriver with a neon lamp onto the Neutral wire it will glow just as if it was Live, because it is being fed with a very small current coming from the Live supply via the plugged-in appliance(s) to the Neutral wire.

If you unplug all appliances, lights and whatever else may be connected to the circuit, the Neutral will no longer seem to be Live because there is no longer any path from it to the Live supply.


Even if there is a GFCI or an RCD in the circuit that too is unlikely to trip in this situation because the test current is so small and is of the same size - an equal current flow - in both the Live and the Neutral wires.

A "Disconnected Neutral" fault condition is VERY UNSAFE because somebody who does not know about the danger could easily touch the Neutral wire and get a bad shock whilst trying to find out why no appliances work when they are plugged into a circuit that actually has such a "Disconnected Neutral" fault condition.

Grounding

Electricity naturally flows to the earth, or to ground, through anything that will conduct electrical current. Pwedeng dumaan ang kuryente sa katawan ng tao na minsan nagdudulot ng fatal results, trying to make a path to the ground.

Kung ang appliance or tool ay faulty, or shorted, for example, pipilitin ng kuryente na magkaroon ng path to ground gaya ng nangyayari kapg KUMIKIDLAT. Kaya, dapat grounded ang mga appliances natin at iba pang electrical loads.

Well, bakit kailangan natin ng ground wire?? Kung tutuusin, pwede gumana ang appliance kahit wala nito because it is not a part of the conducting path which supplies electricity to the appliance.

Kung tutuusin, if the ground wire is is broken or removed, you will normally not be able to tell the difference. But if high voltage has gotten in contact with the case, there may be a shock hazard. In the absence of the ground wire, shock hazard conditions will often not cause the breaker to trip unless the circuit has a ground fault interrupter in it.

Part of the role of the ground wire is to force the breaker to trip by supplying a path to ground if a "hot" wire comes in contact with the metal case of the appliance.



Sa upper part ng diagram, makikita mo ang 3-wire system. Ang ground wire ay coded with "GREEN COLOR". In the event na magkaroon ng electrical fault, at TUMAAS MASYADO ang boltahe, kailangan magtrip agad ng circuit breaker para maputol ang linya.

Kung GROUNDED ang electrical system natin, voltage), ang ground wire ngayon ang dadaaanan ng mataas na current (resulta ng mataas na voltahe), making the circuit breaker TRIP OFF.








Three-Prong Plugs
Siguro mapapansin mong karamihan sa mga outlets sa bahay ay may tatlong butas. Marami kasi ngayon ang meron nang three-prong plugs.

Dalawang prong para sa daanan ng current at ang pangatlong prong para sa grounding. Karaniwan makikita sa stoves natin, sa ref at sa sa computer.
Wag na kayong magtaka nun kasi ibig lang sabihin, safe tayo.



GFCI. "ground fault circuit interrupter"
These are usually installed in wall-mounted receptacles in areas where electricity and water are most likely to come in contact, such as bathrooms, laundry rooms, kitchens, and outdoors. Mas delikado kasi tayo sa mga wet areas
kung saan pwede makadaloy ang kuryente.


Meron tong mga button pasa sa TEST at RESET. GFCIs monitor electric current and can switch a circuit off before injury occurs. Alam nyo din ba, na karamihan ngayon sa mga electric hair dryers are equipped with GFCI on their plugs?? Well, dapat lang din di ba?