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    identify torroidal transformer amperage

    hello, i recycled a torroidal transformer from a speaker, i want to know how much amps of this transformer, olease help me identify, i will be using this to build my bench psu
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    #2
    Re: identify torroidal transformer amperage

    Geometrical dimensions of the transformer, weight, cross-section of the wires of the primary and secondary windings ?

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      #3
      Re: identify torroidal transformer amperage

      Originally posted by kasfamily View Post
      Geometrical dimensions of the transformer, weight, cross-section of the wires of the primary and secondary windings ?
      That is interesting using weight and cross-section of windings. Most likely you would not need the dimensions as you have the voltage rating of the primary and secondary. I would image only a certain cross-section of a primary and secondary can weigh that much and deliver that voltage?

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        #4
        Re: identify torroidal transformer amperage

        Originally posted by juntmeako View Post
        hello, i recycled a torroidal transformer from a speaker, i want to know how much amps of this transformer, olease help me identify, i will be using this to build my bench psu
        Do you still have the device that this came out of it should have data plate on it so you can get a rough estimate of it amperage

        One note I would first start by putting a rectifier diode assembly with no load on it for an hour so you have a reference point and go from there

        Then I would just estimate it current by putting one amp load let it run for an hour and take it temperature and if not that warm then go to 2 amp load and keep going up as long as your transformer does not get so hot that you can not keep your hands on it

        I did a quick search for audio toroidal transformer and most of them that I saw were in a amperage range of 1 to 3 amps
        Last edited by sam_sam_sam; 05-14-2022, 02:40 AM.
        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

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          #5
          Re: identify torroidal transformer amperage

          hi sam, i only have the transformer now, yeah i connected a bridge rectifier without caps and load, i run it like that for almost an hoir, the temps of the transformer felt like normal, not hot , jus normal temp i have no thermal scanner to exactly do temp meas, one thing i did not do is to put a load on it, anyway can you guess the amps based on its marking? BX1201

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            #6
            Re: identify torroidal transformer amperage

            Originally posted by juntmeako View Post
            hi sam, i only have the transformer now, yeah i connected a bridge rectifier without caps and load, i run it like that for almost an hoir, the temps of the transformer felt like normal, not hot , jus normal temp i have no thermal scanner to exactly do temp meas, one thing i did not do is to put a load on it, anyway can you guess the amps based on its marking? BX1201
            Here is a link for you.

            https://www.electricaltechnology.org...nsformers.html

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              #7
              Re: identify torroidal transformer amperage

              thanks, btw, it has 1.5A fuse on primary winding

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                #8
                Re: identify torroidal transformer amperage

                Originally posted by juntmeako View Post
                thanks, btw, it has 1.5A fuse on primary winding
                As I remember if one has say 200 volts on the primary winding at 1.5A and you drop down to say12 volts on the secondary your current will be inversely proportional to the primary. You would set up a proportion like 200/12=X/1.5 Solve for x to get current in secondary.
                Last edited by keeney123; 05-16-2022, 04:36 PM.

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                  #9
                  Re: identify torroidal transformer amperage

                  hmm so 230V/28V = 8V
                  and 8V/1.5A = 5A, so my transformer output current is upto 5A?

                  230V primary, 28V-0-28V secondary

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                    #10
                    Re: identify torroidal transformer amperage

                    Originally posted by juntmeako View Post
                    hmm so 230V/28V = 8V
                    and 8V/1.5A = 5A, so my transformer output current is upto 5A?

                    230V primary, 28V-0-28V secondary
                    Is the 28V-0-28V one winding with +28 volts, center tap 0V, and -28Volts? if it is one winding than the voltage difference is 56 volts. You would then be going from 230V to 56V. If they are separate winding then you would figure them individually. Also, remember that the fuse rating is 1.5 A so the actual current will be less. Usually a engineer will make a safety factor of 40%. The actual current could be 1.5x.6= 0.9A I believe a 1A 230 primary is a realistic supply.
                    Last edited by keeney123; 05-17-2022, 11:44 PM.

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                      #11
                      Re: identify torroidal transformer amperage

                      its dual secondary, there are 3 wires is sencondary, blue-black-blue(28-0-28)

                      my transformer weighs 1.25kg, its outer diameter is 94mm, height 39mm, inner diameter is 45mm. its rough measurement

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                        #12
                        Re: identify torroidal transformer amperage

                        correction, its not dual secondary, its center tapped

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                          #13
                          Re: identify torroidal transformer amperage

                          110VA

                          based on weight and outputs
                          using these as reference:
                          https://uk.rs-online.com/web/p/toroi...ormers/2238049
                          https://uk.rs-online.com/web/p/toroi...ormers/7581042

                          Comment


                            #14
                            Re: identify torroidal transformer amperage

                            Originally posted by juntmeako View Post
                            correction, its not dual secondary, its center tapped
                            What I have read is that normally with a transformer when figuring out VA they use a power factor of 0.8 but, these types of transformers are more efficient for the power factor. It becomes 0.9 This can be looked upped online on how to figure it out. Basic understanding is that the primary has just so much power figuring on current and voltage. That power will be transmitted through to the secondary at a loss. Although the magnetic transference is 99% efficient i guess the power takes a hit by 10% in this case.

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