step up and step down Auto transformer

Discussion in 'General Electronics Chat' started by superway, Jul 12, 2011.

  1. superway

    Thread Starter Active Member

    Oct 19, 2009
    128
    0
    Hello,

    The link below is a FW-X240 Auto transformer stepup and stepdown.
    www.outbackpower.com/pdf/manuals/fw-​x240.pdf

    I looked on pdf file, I could not find which wire# is primary and secondary.
    If it is step down, apply 240v on the winding# and will get 120v from another widnding. How do we verify which wires are used for step down voltage?

    Thanks

    ken
     
  2. SamAtOz

    New Member

    Jun 29, 2011
    7
    0
    Ken,

    The step down wiring is shown in section 1:9 of the manual. If you also look at the diagram on Section 1:5 it will show the colour codes for the transformer wires.
     
  3. praondevou

    AAC Fanatic!

    Jul 9, 2011
    2,936
    488
    I didn't get why they call it autotransformer, if it has two separate and equal windings.

    But with this info

    "Two identical windings:
    • Winding one is between leads #1 and #2
    • Winding two is between leads #3 and #4
    • The start for each winding are on lead #1 and on lead #3"

    and the drawing on page 6 you know at least how it was built.

    1 and 3 is the beginning of each winding, so in their diagrams they connect 2 to 3. Doing so you put both windings in series.
    So if you want a simple step-up you connect 2 and 3 and put your 120VAC between 1 and 2. Then you'll have 240VAC between 1 and 4. Or you connect 240VAC to 1 and 4 and will have 120VAC between 1 and 2 (and 3 and 4). Correct?
     
    Last edited: Jul 12, 2011
  4. superway

    Thread Starter Active Member

    Oct 19, 2009
    128
    0
    Thank you very much.

    ken
     
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