In AC circuits, ang wave ng boltahe at ng current ay di nagkakasabay, o parating out-of-phase. Usually sa power system, the current wave lags the voltage wave due to predominantly inductive loads, e.g., motors. Pag nagkaroon ng phase difference, yun din ang nagiging sukatan ng power factor.
Sa power factor natin malalaman gaano ka-efficient ang equipment sa pag convert ng current into useful output . Ang ideal kasi kung ano yung energy supply mo ay yun din ang dapat ginagamit. Walang power loss.
Sunday, March 7, 2010
Tuesday, October 20, 2009
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!
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!
Wednesday, October 7, 2009
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.
Sunday, October 4, 2009
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 0o phase difference, the pointer is at the "12 o’clock" position and the two AC generators are in phase.
Wednesday, September 30, 2009
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.
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.
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.
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.
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.
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