12 dc amp power supply

Discussion in 'The Projects Forum' started by boattail, Sep 27, 2009.

  1. boattail

    Thread Starter New Member

    Sep 24, 2009
    2
    0
    Hello, New user to site. I have a 12 vdc 45 amp power supply that I am trying to understand how it tics. I have basic knowledge of electronics and a digital fluke for testing. What I know about the circuit is:
    120 AC Input-full wave rec.-high voltage current switches(4 trans) on heat sync-center tap transformer-full wave rec (4 trans)on heat sync-12 output.
    My problem was the current switches went out. I have replaced them but still no output.
    What I am having a hard time getting through my head is this. The full wave rec gets me the DC for the current switches but then don't I need AC for the center-tap-transformer to work. After the transformer the full waves will rectify it for the output.
    What am I not understanding about this circuit?
    Also I have no schematic to refer to. All I have is the model number.
    Any help would be appreciated.
    Thanks in advance
     
  2. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Well, one of the first things to track down is a schematic.

    What is the manufacturer of the power supply, and what is the model number?
     
  3. zimbarak

    Active Member

    Feb 8, 2009
    56
    0
    is it a switch mode power supplY ? the circuit inside has a switching transistor with more than output for the transformer ?
     
  4. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Very likely that it is a switching-type supply. The incoming 50/60Hz AC is rectified to DC and filtered. Then the DC is switched at high frequency (perhaps 20kHz-200kHz) through a toroidal transformer. A transformer that was capable of 45A output with a 50/60Hz input would be very large and heavy. The use of higher frequency switching allows the use of much smaller transformers.

    Seeing that you have four current switches, it is very likely that they are configured as an "H" bridge. This allows the direction of current through the coil to be reversed.
     
  5. boattail

    Thread Starter New Member

    Sep 24, 2009
    2
    0
    Hello SGT, First, thanks for the reply. I read your info and to this newb it makes sense. The model # was CS 4500, which when googled, tells me that it is a Centerion supply. After reading about the H bridge and the torod I believe my next step is to find the high speed switch (trans.) that turns on and off the current switches. Right?
     
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