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Transformer power with central tap

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I have a toroidal transformer with central branch whose label says 38.5 - 0 - 38.5V 220VA, this means that between the ends of the winding there are 77V. It also has two smaller windings of 10VA each. My question is whether to calculate the maximum winding current of 38.5 I use the formula 220VA / 38.5A or if it is used is all the winding voltage that is 220VA / 77V?

Thanks in advance
  • 1 month ago

    Avatar de elektomaq

    There is a lot of confusion in the units you have used
    V - VA -A are not the same thing
    Review your question and correct it with the exact data
    By dividing the primary voltage over the secondary voltage, you will only get the transformation ratio, not the power but there are doubts since if what you put are "220V" is primary voltage, instead if they are "220 VA" it would be the power of the transformer

  • 1 month ago

    Avatar de ricbevi

    Upload a clear photo of the label and save confusion (or not).

  • 1 month ago

    Avatar de gyeraldh

    It is 38.5V (Volt), 220VA (Volt-Ampere). The formula that doubted the current is whether I = 220VA / 38.5V or I = 220VA / 77V is calculated. But it is already clear to me that it is 220/77 which is the power of the label on the voltage between the ends of the secondary (secondary with 38.5V dual or 77V end to end). Thank you

1 Proposed Solution

greetings, you must divide the transformer VAs between 77v, to get the current, which will be the result of a full-wave rectifier with central tab,
  • 1 month ago

    Avatar de gyeraldh

    Correct thanks. For those who have doubts about the units are well written. 38.5 Volts, 220 Volt-Ampere.