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  • joesitohang 3:44 pm on October 27, 2008 Permalink | Reply
    Tags: ac motor troubleshooting   

    3 Phase alternating current Motor Troubleshooting 

    This is a BRIEF COURSE INTENDED TO ACQUAINT YOU WITH BASIC electric MOTOR TROUBLESHOOTING AND testing

    CAUTION

    If you have not been trained in how to work safely near live electrical circuits, do not attempt to measure line voltages. Find someone who has been trained in electrical safety and let him or her take voltage readings. Great care is needed to eliminate the possibility of DEATH or serious injury.

    ALWAYS disconnect the power and verify all parts are dead before touching or handling any parts of electrical equipment. Lock out and tag out all electrical circuits. Test for voltage before touching any components. Check for and eliminate the danger of “stored energy” caused by raised or spring-loaded equipment.

    The basic test equipment you will need to troubleshoot AC motors includes:

    AC voltmeter

    AC clamp-on ammeter

    Ohmmeter

    Megohmmeter

    Voltage Tests

    Voltage is the term used to describe the magnitude of the Electro-Motive Force, or in other words, the pressure at which electrons are being forced through a circuit.

    It’s current that kills, but it’s voltage that really establishes the level of danger involved in working with electricity. Knowing the voltage you are working with enables you to take appropriate steps to safeguard yourself and those working near you from electrocution.

    Typical Delta/Wye Transformer Connections

    (More …)

     
    • dave wagman 10:47 pm on May 17, 2009 Permalink | Reply

      I am an hvac tech and Im working on a 3PH rooftop unit that the blower runs in reverse .We switch legs and runs proper rotation.2 days later same thing happens again .so far this has happen 3x in a week on the same unit. I check volts and amp draw L1 7.4A 120v to grnd. L2 7.4A 120v to grnd. L3 7.1A 120v to grnd . Voltage checks were done coming out of overload.can u tell me what would cause this condition .my next step is replacing the motor. thanks for any explaination. Baffled Tech ??

      • Rick C. 8:14 pm on September 7, 2009 Permalink | Reply

        Some motors will run in reverse if they are spinning already when power is energized. This can happen if another blower is hooked to the same air duct or a draft is created that causes the problem blower to spin in reverse. You might check to see if this blower is running backwards while power is off. Good Luck with your problem

    • Joe Sitohang 7:31 pm on May 18, 2009 Permalink | Reply

      for your case i think you need to check the lines sequence by “3 Phase rotation tester” please verify the R-S-T sequence are correct before you decide to replace the motors

    • Yousif 1:39 am on May 22, 2009 Permalink | Reply

      I have electrical motor three phase, vibration symptoms in this motor as fallows;

      1-Twice running speed is excitation with running speed at 1800 rpm. I did high resolution and there is no side band which is confirmed there no winding problem. I checked current phase and found the following>

      phase A is 121A
      phase B is 118 A
      phase C is 130 A

      My question, why there is twice running speed is excitation with running speed and make it beating (running speed with twic running speed are jonied toghther), running speed is constant.

    • Joe Sitohang 1:11 pm on May 22, 2009 Permalink | Reply

      @ Yousif
      Please verify your motor alignment are correct or uncorrect

    • Tim McWha 10:55 am on December 15, 2009 Permalink | Reply

      I work for a power company and I have a customer complaining about his VFD/Motor running with 1 of the three phases having 40% lower current than the other two phases. I put a recorder on the transformer serving the customer and recorded good and balanced voltage. Because the transformer serves other loads besides the VFD/Motor, I don’t know if the current is balanced at the transformer.
      The customer rolled the phase connections to eliminate the motor as the possible problem. The result: the low current went with the wire. Thus eliminating the motor as suspect.
      I can understand High current on 1 phase, but “Low Current”? Please Help.

    • Joe Sitohang 10:15 pm on February 16, 2010 Permalink | Reply

      Dear Tim McWha,
      low current due to unbalanced load between phases, if you are sure that the motor does not have a problem then you should double check the total usage of the transformer, if necessary, move some phases of high load to low load phase

  • joesitohang 5:11 pm on September 13, 2008 Permalink | Reply
    Tags:   

    Analogi cinta seorang elektrik… 

    Beberapa komen di artikelku yang lalu mengatakan kalo orang elektrik itu kurang baik terlalu melankolis, bisa-bisa fasa grounding jadi api hehehe…, orang elektrik ternyata bisa juga ya bikin puisi? Nah lo, orang elektrik juga manusia kan? Itu mungkin sudah mewakili semua pertanyaan yaaa…

    Terakhir, ada yang minta bikin puisi tentang kelistrikan, misal Voltase….Baiklah sobat, bukan saja puisi yg kubikin tentang kelistrikan, artikel ini lebih dari sekedar puisi.

    Secara umum tapi tak lazim disebut, Listrik adalah Perbedaan Potensial Diantara Dua Titik, Perbedaan Potensial ini dikenal dengan Tegangan (Voltage). Dalam Operasi Tenaga listrik khususnya pembangkitan energi listrik bertenaga diesel skala besar (secara aku sekarang di divisi ini) ada istilah yang disebut Synchronization atau sinkronisasi atau parallel antar unit satu dengan unit lainnya atau antar unit satu dengan unit grid/ Line system.

    (More …)

     
    • Elys Welt 10:24 am on September 14, 2008 Permalink | Reply

      ah paragraph yang terakhir itu begitu romatisnya :)
      thanks ya kunjungannya

    • Silo 1:18 pm on September 14, 2008 Permalink | Reply

      Siip analogi yang bagus, kalau perlu tambah puisinya deh sekalian :)
      Tapi jangan di analogikan cinta ibrata listrik kesetrum terus bengkak yah ha..ha

    • joe Sitohang 10:49 am on September 15, 2008 Permalink | Reply

      @ Elys Welt;
      stuju dong perempuan itu bola lampu hemat energi? heheh…*kabur*

      @ Silo;
      cinta ibarat listrik ada persamaanya lho mas, sama2 punya magnet. btw, thanks buat kunjungannya….

      cheers,
      -joe-

    • ManusiaSuper 4:48 pm on September 15, 2008 Permalink | Reply

      Ah, romantis dalam bentuk yang berbeda,,,

    • joe Sitohang 5:17 pm on September 15, 2008 Permalink | Reply

      @ ManusiaSuper:
      Ah..hirnya datang juga, :D nah loe….!

    • emyou 10:47 am on September 17, 2008 Permalink | Reply

      that’s simply romantic :)

    • Nesia! 6:48 pm on September 17, 2008 Permalink | Reply

      hehehe… truely romantic, lae… tp ada curangnya juga ;)

      bola lampu boleh bolak-balik diganti, tp pembangkit listriknya itu-itu juga…

      just kidding… saya selalu kagum bila ada yang mampu menguraikan hal-hal teknis dalam bahasa yang (relatif) mudah dicerna.

      salam.

    • carbonized 12:01 am on September 21, 2008 Permalink | Reply

      Oh…. seandainya aku seorang perempuan!!
      eiiiitttt, tunggu dulu.
      coba bayangin seandainya terjadi overload pada pembangkit, apa jadinya sama tuh lampu ya?
      Hayoooooooo, tolong dijawab dengan bahasa ilmiah

    • joe Sitohang 10:27 am on September 22, 2008 Permalink | Reply

      @ Nesia;
      aku juga kagum dengan Naked mind lae itu…..:D

      @carbonized;
      dijawab dgn bahasa ilmiah atau dibayangin nih? hehehe….
      kalo dibayangin>> tuh lampu kemungkinan kedap-kedip (kayak lampu disco) sesekali penting jg nih biar hubungan lebih berasa *ngeles modeOn*
      kalo ilmiahnya>> Pembangkit Tidak akan overload selama pengaturan pembagian beban dilakukan dengan benar, (makanya jgn mencuri listrik, biar gak overload)

    • Febiola Sitohang 1:09 pm on November 10, 2008 Permalink | Reply

      klo suka trun naik sekringna..trs apa yg terjadi dgn bola lampuna bukanna jadina putus… salah dmna tuh… nambah arus aja kali ya…

    • joe Sitohang 2:51 pm on November 10, 2008 Permalink | Reply

      @ Febiola Sitohang;
      sedikit meluruskan ya namboru….
      yang suka turun naik itu MCB (Miniature Circuit Breaker), bukan sekring…..stuju yaaa

      nah, pointnya mungkin maksud namboruku ini adalah bagaimana kalo aliran listriknya ndak stabil, apa yg terjadi dengan bola lampu?

      kalo bola lampu yg berkualitas biasanya akan tahan dengan ketidakstabilan listrik setidaknya plus minus 10% dari tegangan nominal listrik… dan yang jelas si bola lampu gak salah heheheheh….

  • joesitohang 12:54 pm on September 2, 2008 Permalink | Reply
    Tags: Listrik   

    Persoalan2 Operasi Sistem Tenaga Listrik 

    Berikut beberapa persoalan-persoalan yang perlu diperhatikan dalam Operasi Sistem Tenaga Listrik, Tulisan ini ber-orientasi pada sistem Pembangkit Listrik Tenaga Diesel dimana tempat aku kami bekerja saat ini. smoga bermanfaat bagi yang membutuhkan….

    progress repair alternator (baru nurunin exciter...)

    progress repair alternator (baru nurunin exciter...)

    1. Pengaturan Frekuensi

    Daya yang dibangkitkan dalam sistem tenaga listrik harus selalu sama dengan beban sistem, hal ini diamati melalui frekuensi sistem. Kalau daya yang dibangkitkan dalam sistem lebih kecil daripada beban sistem maka frekuensi turun dan sebaliknya apabila daya yang dibangkitkan lebih besar daripada beban maka frekuensi naik. (More …)

     
    • achoey sang khilaf 11:46 am on September 7, 2008 Permalink | Reply

      wah hebat sobat

    • RItool 10:38 pm on December 16, 2008 Permalink | Reply

      Pembebanan yang tak seimbang diantara fasa r s t , dapat mempercepat kerusakan mesin pembangkit,
      disamping itu masalah maintenance rutin nya sangat perlu diperhatikan.

      Oke …. lanjut lae !

    • joe Sitohang 2:51 pm on December 26, 2008 Permalink | Reply

      @ RItool;
      he..he… tau aja mr.RItool

      Sonchou lae !
      -JoeSitohang-

    • ajun 5:07 pm on January 18, 2009 Permalink | Reply

      mo nanya leh ngk
      kalo misalnya terjadi gangguan di feeder tapi yang baca pengaman pada generator kira2 persoalannya dmana
      nih untuk sistem 20 kv

    • joe Sitohang 9:18 am on January 19, 2009 Permalink | Reply

      @ ajun
      kemungkinannya banyak sekali yaa, bisa saja relay pengaman feeder jenuh atau malah tidak kerja samasekali (Rusak) kemudian relay pengaman generator akan merespon kondisi tsb dan atas settingan eksis tentunya akan muncul perintah tertentu, bisa melepas CB atau malah men-Trip Engine, utk menghindari trouble ini perlu dilakukan uji individual rutin baik pada perangkat pengaman feeder maupun perangkat pengaman generator itu sendiri, pastikan setting besaran pada system pengaman anda sudah benar dan bekerja normal, smoga membantu.

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