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.