Transformer blues....Pricey buggers HELP!

Discussion in 'The Projects Forum' started by kalikid1210, Sep 5, 2009.

  1. kalikid1210

    Thread Starter Member

    Jul 15, 2008
    Here is the schematic (CLICK on the image, which will open in a new window) for a power supply I am using to power a 24Vdc, 135W, 10A scooter motor.


    I went to and the lil beast was over 50.00! Please tell me that there's a more economical way.

    But, yes there's a but, I would be interested in a pricey, up to $75.00, transformer if it were very small. In other words the smaller the better.

    Size is a definite concern in this PS's construction. Is it possible that it could the size of a pack of cigarettes? I don't smoke btw...yet.

    Would a toroid transformer make the grade?
  2. Audioguru

    New Member

    Dec 20, 2007
    Your filter capacitor is much too small for a 10A load. It will also cost a small fortune.

    My powerful appliance motors are AC and run directly from the mains without a transformer, rectifier and filter capacitor.
  3. tkng211

    Well-Known Member

    Jan 4, 2008
    If you wanna have a small sized one, better get a switching power supply instead of using steel core transformers.
  4. SgtWookie


    Jul 17, 2007
    One of the above numbers is incorrect.
    A) 135W @ 10A = 13.5V
    B) 24V @ 10A = 240W
    C) 24V @ 135W = 5.625A.
    Pick one; A, B or C.

    MPJA to the rescue; 24V @12.5A for under $25 in a switching supply:
    Larger than you want, but you can't have everything.

    Toroidal transformers are very prevalent in switching supplies. They can make them small because they operate at much higher frequencies than 50Hz/60Hz. However, you'd have to design and build a complete switching power supply, which would be a lengthy, complex and expensive task for a novice.
  5. jj_alukkas

    Well-Known Member

    Jan 8, 2009
    A switching mode power supply at 24V 10A can never be made at the size of a cigarette pack though it will be a smaller than the corresponding transformer.And as SgtWookie stated, building it isn't easy either.
  6. kalikid1210

    Thread Starter Member

    Jul 15, 2008
    Thank you all... for switching power supply first thing Tuesday morning...end of story.

    Known when to say when