Isolation transformer

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  • llonen
    Badcaps Veteran
    • Sep 2014
    • 495
    • hampshire

    #1

    Isolation transformer

    Firstly I feel this is something I should already know the answer to but it eludes me. Anyways I have been in the repair business for some 15 years or longer and I still don't have an isolation transformer yeah (bad me). So I starts looking at options for 2-3kw isolation transformers and and the price is a little more than I would like to pay out.

    So I gets thinking I have a number of 230v/110 CTE step-down isolation transformers for working on power tools which I also get in for repair from time to time. They are around 3kva rating is there any reason I can't connect two of these back to back to make a 1:1 isolation transformer.
  • Agent24
    I see dead caps
    • Oct 2007
    • 4913
    • New Zealand

    #2
    Re: Isolation transformer

    Assuming they are in fact real transformers, then sure.

    Just make sure it's not actually an autotransformer - some of those step-down ones are. And those won't give you any isolation at all!
    "Tantalum for the brave, Solid Aluminium for the wise, Wet Electrolytic for the adventurous"
    -David VanHorn

    Comment

    • CapLeaker
      Leaking Member
      • Dec 2014
      • 7986
      • Canada

      #3
      Re: Isolation transformer

      I found plenty isolation transformers in a regional ham flea market. I've got one, but hardly use it. I guess that depends on what one repairs.

      Comment

      • llonen
        Badcaps Veteran
        • Sep 2014
        • 495
        • hampshire

        #4
        Re: Isolation transformer

        To be honest its not something I have ever felt the need to setup, it might be useful for scoping smps I suppose but I have a battery scope for that furthermore most of them are such cookie cutter designs the need to scope out stuff on them is largely irrelevant to me.

        I will have a go at setting this up but I am certainly not paying the going prices for 2-3 kva isoloation transformers. So its a couple of 230/110 cte transformers then, I might need to obtain one more since two are in regular use and one is used for testing 110 volt tools which leaves one spare. I will let you know how I get on.

        Comment

        • Agent24
          I see dead caps
          • Oct 2007
          • 4913
          • New Zealand

          #5
          Re: Isolation transformer

          Originally posted by llonen
          It might be useful for scoping smps I suppose but I have a battery scope for that
          True, that will prevent you from shorting something to ground, but it will not protect you from a direct mains connection.

          Using the isolation for the DUT, with a battery scope or not, will be a bit safer.
          "Tantalum for the brave, Solid Aluminium for the wise, Wet Electrolytic for the adventurous"
          -David VanHorn

          Comment

          • budm
            Badcaps Legend
            • Feb 2010
            • 40746
            • USA

            #6
            Re: Isolation transformer

            Originally posted by agent24
            true, that will prevent you from shorting something to ground, but it will not protect you from a direct mains connection.

            Using the isolation for the dut, with a battery scope or not, will be a bit safer.
            +1.
            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:
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            Comment

            • petehall347
              Badcaps Legend
              • Jan 2015
              • 4423
              • United Kingdom

              #7
              Re: Isolation transformer

              be careful using 2 yellow bricks like that .
              Last edited by petehall347; 05-19-2019, 06:20 PM.

              Comment

              • budm
                Badcaps Legend
                • Feb 2010
                • 40746
                • USA

                #8
                Re: Isolation transformer

                Originally posted by llonen
                To be honest its not something I have ever felt the need to setup, it might be useful for scoping smps I suppose but I have a battery scope for that furthermore most of them are such cookie cutter designs the need to scope out stuff on them is largely irrelevant to me.

                I will have a go at setting this up but I am certainly not paying the going prices for 2-3 kva isoloation transformers. So its a couple of 230/110 cte transformers then, I might need to obtain one more since two are in regular use and one is used for testing 110 volt tools which leaves one spare. I will let you know how I get on.
                I would verify that they are not Auto-Transformer, you can easily verify by checking the resistance between the windings.
                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

                • llonen
                  Badcaps Veteran
                  • Sep 2014
                  • 495
                  • hampshire

                  #9
                  Re: Isolation transformer

                  Already checked on the one spare now looking for another

                  Comment

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