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What's this transformer for and how to find in on aliexpress?

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    What's this transformer for and how to find in on aliexpress?

    Hi!

    I interested in trasformer on attach image. It's used on power supply. What keywords should I use to each for replacement on sites like aliexpress?


    I tried to search for "high frequency transformer" but I didnt seem to find this one. It seems to have two 30 turn output side and one 20 turn winding on input side.

    Any ideas what the use of 2 outputs if both have same number of turns?
    Attached Files

    #2
    Re: What's this transformer for and how to find in on aliexpress?

    There are probably millions of different transformers out there for many different uses. You need to understand what the circuit does to know how that transformer is used.

    To me, this looks like a driver transformer of some sort and not a power transformer, but I really couldn't say more without at least some detailed pictures of the device.

    Comment


      #3
      Re: What's this transformer for and how to find in on aliexpress?

      1) Is the transformer bad? In which way?

      2) How about providing straight shots pictures of the whole top and bottom side of the board.

      3) That transformer does look like for Gate drive transformer.

      4) Did you unwind the windings to get the turn count?
      Never stop learning
      Basic LCD TV and Monitor troubleshooting guides.
      http://www.badcaps.net/forum/showthr...956#post305956

      Voltage Regulator (LDO) testing:
      http://www.badcaps.net/forum/showthr...999#post300999

      Inverter testing using old CFL:
      http://www.badcaps.net/forum/showthr...er+testing+cfl

      Tear down pictures : Hit the ">" Show Albums and stories" on the left side
      http://s807.photobucket.com/user/budm/library/

      TV Factory reset codes listing:
      http://www.badcaps.net/forum/showthread.php?t=24809

      Comment


        #4
        Re: What's this transformer for and how to find in on aliexpress?

        Originally posted by LearningToRepair View Post
        Hi!

        I interested in trasformer on attach image. It's used on power supply. What keywords should I use to each for replacement on sites like aliexpress?


        I tried to search for "high frequency transformer" but I didnt seem to find this one. It seems to have two 30 turn output side and one 20 turn winding on input side.

        Any ideas what the use of 2 outputs if both have same number of turns?
        How do you know the number of turns? Have you UNWOUND the core and counted? Or, is the transformer still operational and you observed the voltage gain?

        [If operational, then why are you replacing it?]

        Transformers are often wound specifically for a particular design. You may never find a "drop in" replacement for that particular one.

        Comment


          #5
          Re: What's this transformer for and how to find in on aliexpress?

          This transformer seems more like gate driver transformer for powerful converter IGBTs or FETs.
          If this device where this transformer is, is known manufacturer product then you may find replacement transformer but if not then you can make it yourself if you know how to make it.

          But if this smps operate 70 or more kHz then you need take very special care. If you want only replicate - exactly same wire and turns of windings exactly same direction, core must be same shape and material N87, N97, 3C94, 3C95 or better (power ferrite) leads you the target if the controller IC is not any exotic.
          If this device is chinese then 99% that you can't find it in the store

          Comment


            #6
            Re: What's this transformer for and how to find in on aliexpress?

            Hi!

            Yes counted the number of turns. Originally I had to unsolder this transformer to get access to components that I could not otherwise. But then later I accidentally dropped it on floor and the plastic structure that was holding the pins broke. At first I thought that it's no big problem, that I could easily find the replacement once I know turn ratio and since it was already broken I simply counted the winding. Well it turned out it that finding replacement was not easy task.

            How about providing straight shots pictures of the whole top and bottom side of the board.
            Here is image about this transformer:


            And here is bottom side:


            But if this smps operate 70 or more kHz then you need take very special care. If you want only replicate - exactly same wire and turns of windings exactly same direction,
            Yes, it can go upto 100 kHz. Why is it so important? So far I only knew that DC cares about direction, never knew that AC also wants right direction. Tell me more about it. And why is it not important for lower frequencies?

            I was actually about to ask about creating it on my own. Like 3D printing new plastic part and then winding it again. Sadly I did not memorize winding direction because it never occurred to me that it could be important.
            As for re-creating it my self, does anyone know what happens when I dont get exactly the same wire? For example what happens if I use larger diameter wire instead? Does it simply increase the maximum allowed current or what would happen?

            core must be same shape and material
            Yes, i still have the metal core and plastic part is good enough that I can take measurements from it and 3D print it.

            You seem to know more about it. Do you know what's that transformer could be used for? I mean 2:3 ratio doesn't seem to increase voltage that much. Is it for some kind of isolation?
            Attached Files

            Comment


              #7
              Re: What's this transformer for and how to find in on aliexpress?

              So much to learn.
              Just do a search on 'how to design Gate drive transformer'
              https://talema.com/gate-drive-transf...n-methodology/
              https://talema.com/gate-drive-transf...onsiderations/

              https://www.coilcraft.com/en-us/edu/...-transformers/

              https://cdn.badcaps-static.com/pdfs/...6f10bae659.pdf

              https://www.powerelectronics.com/tec...e-transformers
              Last edited by budm; 10-14-2020, 02:17 PM.
              Never stop learning
              Basic LCD TV and Monitor troubleshooting guides.
              http://www.badcaps.net/forum/showthr...956#post305956

              Voltage Regulator (LDO) testing:
              http://www.badcaps.net/forum/showthr...999#post300999

              Inverter testing using old CFL:
              http://www.badcaps.net/forum/showthr...er+testing+cfl

              Tear down pictures : Hit the ">" Show Albums and stories" on the left side
              http://s807.photobucket.com/user/budm/library/

              TV Factory reset codes listing:
              http://www.badcaps.net/forum/showthread.php?t=24809

              Comment


                #8
                Re: What's this transformer for and how to find in on aliexpress?

                BTW, The Phase of the windings must also be observed.
                Never stop learning
                Basic LCD TV and Monitor troubleshooting guides.
                http://www.badcaps.net/forum/showthr...956#post305956

                Voltage Regulator (LDO) testing:
                http://www.badcaps.net/forum/showthr...999#post300999

                Inverter testing using old CFL:
                http://www.badcaps.net/forum/showthr...er+testing+cfl

                Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                http://s807.photobucket.com/user/budm/library/

                TV Factory reset codes listing:
                http://www.badcaps.net/forum/showthread.php?t=24809

                Comment


                  #9
                  Re: What's this transformer for and how to find in on aliexpress?

                  Thank.

                  I still have questions:
                  1) What happens when I am unable to find exact same diameter wire? Would larger diameter wire also work or will something blow up then?

                  2) Why is the directions of turns important as mentioned by previous replier?

                  3) Is there some standard wire size that is commonly used in gate drive transformers or is the only way to go shopping with wire from previous transformer and visually compare the diameter?

                  Comment


                    #10
                    Re: What's this transformer for and how to find in on aliexpress?

                    You have the internet so you need to do the research.
                    Do the search on how to figure out what the wire gauge should be for your requirement.
                    https://energycentral.com/c/iu/transformer-polarity
                    https://circuitdigest.com/article/un...n-transformers
                    Right now you do not have the spec of the transformer, but you do have the original wire so why not use what you already have.
                    You are trying to learn about building transformer that you do not know what the requirement are and you need to understand how transformer works, it is not simple task.
                    BTW, you do understand what the purpose of Gate drive transformer is, and why the phasing is important to get it correctly, right?
                    Last edited by budm; 11-02-2020, 09:50 PM.
                    Never stop learning
                    Basic LCD TV and Monitor troubleshooting guides.
                    http://www.badcaps.net/forum/showthr...956#post305956

                    Voltage Regulator (LDO) testing:
                    http://www.badcaps.net/forum/showthr...999#post300999

                    Inverter testing using old CFL:
                    http://www.badcaps.net/forum/showthr...er+testing+cfl

                    Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                    http://s807.photobucket.com/user/budm/library/

                    TV Factory reset codes listing:
                    http://www.badcaps.net/forum/showthread.php?t=24809

                    Comment


                      #11
                      Re: What's this transformer for and how to find in on aliexpress?

                      Originally posted by budm View Post
                      You have the internet so you need to do the research.
                      Do the search on how to figure out what the wire gauge should be for your requirement.
                      https://energycentral.com/c/iu/transformer-polarity
                      https://circuitdigest.com/article/un...n-transformers
                      Right now you do not have the spec of the transformer, but you do have the original wire so why not use what you already have.
                      You are trying to learn about building transformer that you do not know what the requirement are and you need to understand how transformer works, it is not simple task.
                      BTW, you do understand what the purpose of Gate drive transformer is, and why the phasing is important to get it correctly, right?

                      Thank you for sharing this information I learned something from it
                      9 PC LCD Monitor
                      6 LCD Flat Screen TV
                      30 Desk Top Switching Power Supply
                      10 Battery Charger Switching Power Supply for Power Tool
                      6 18v Lithium Battery Power Boards for Tool Battery Packs
                      1 XBox 360 Switching Power Supply and M Board
                      25 Servo Drives 220/460 3 Phase
                      6 De-soldering Station Switching Power Supply 1 Power Supply
                      1 Dell Mother Board
                      15 Computer Power Supply
                      1 HP Printer Supply & Control Board * lighting finished it *


                      These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%

                      1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
                      2 Hem Saw Computer Stack Board

                      All of these had CAPs POOF
                      All of the mosfet that are taken out by bad caps

                      Comment


                        #12
                        Re: What's this transformer for and how to find in on aliexpress?

                        I read these but I still did not find out what happens when I use larger diameter wire than I have to (in case I cant use original wire for some reason)? I mean normally I would expect that nothing bad happens from choosing to too large wire but since it is high frequency I am not 100% sure anymore.

                        Comment


                          #13
                          Re: What's this transformer for and how to find in on aliexpress?

                          ^ Larger wire is OK - if you can make it all fit.
                          Smaller wire... will probably work too, but may not be a good idea.
                          Since this is not a power transformer but rather just a signal/driver transformer, smaller wire will probably work without any adverse affects. Nevertheless, try to stick close to what the original wire size was, or use thicker wire if needed... and if really not possible, then go with thinner wire as last choice.

                          Comment

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