Viewing 8 posts - 1 through 8 (of 97 total)
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  • #6741
    maredentro72
    Participant

    Good evening everyone, is a year that “game” ATX power supplies in order to understand how they work and any potential, I bought a dozen and some I disassembled them, how to do an autopsy. In the meantime I searched the network schemes and anything to get more.
    I state that I am neither an expert nor a degree or diploma in electronics but simply an enthusiast for many years.
    I come to the point, I need a double power supply from about 500W and provides me 85+85 volt, if you spend an equal characteristics as minimum transformer 5 times as much and more.
    Then however, I like to experiment and blow up the counter of the light house.
    I run into this site, eyes shone and I already found a few posts that I exchanged with Amilcare.
    Practically integrated use of IR215x family (I prefer the IR2155) as drivers and mosfet IRF740 or IRF840 as power stage, the transformer I realized riavvolgendone one recovered from a ATX, a EI35.
    Now I would like to add the image of the diagram to understand what I mean but I can not.
    Help

    Alberto

    #6743
    Amilcare
    Keymaster
    #6745
    maredentro72
    Participant

    Amilcare always quick in responses.
    here's the scheme:
    SMPS

    #6748
    maredentro72
    Participant

    Schemes that are networked for IR215x family are very minimalist and the rest of the tips I found them here.
    I added the snubber and zenerda 15v for safety,
    I have fried a dozen IR2153 and are now passed to 55 not to mention the mosfet, even them 12 O 14 I do not remember.
    Never mind all recycled materials.
    Now the SMPS is exactly like the scheme and wanted to make it more reliable with a control network and precisely this:
    SMPS limiter
    virtually everything that lies between the small signal transformer in series with the gate of the MOSFET and the transistor 2N5551.
    The only difference is that I have the power 230 rectified and filtered with two capacitors in series while in the Amilcare scheme is monocondensatore.
    I will attach the modified scheme.

    Alberto

    #6750
    maredentro72
    Participant

    Here the scheme illustrated above with inserted the protection.
    SMPS upgrade
    It is not the present value of the bias resistance of the SCR Source, I thought to a value of 4700ohm.
    I hope I have done the exact links; as I mentioned in the post above I used two capacitors in series while SCHEME 2 only has one.
    In this scheme (It is the original) the output transformer is still with a central outlet while in the final there will be two as in the first secondary.
    For the small transformer use a toroid from 12-16mm wrap all around 70 double wire coils from 0.1mm (will find it a problem of this diameter) and 35th to take the central exit.
    For the primary take a couple of turns (monofilari of bifilari? same diameter?).
    I hope I have made too many questions.
    Alberto

    #6752
    Amilcare
    Keymaster

    For eye with the two input capacitance hardly you are able to obtain 500W output. I think that given the losses and the natural aging of components 400W throws them out but no more. The two capacitors in series give a smaller capacity 500uF and considering the rule of thumb for 1W uF accounts are easy to make. In the diagram see two zener diodes in parallel, probably one of the two is too many

    #6754
    maredentro72
    Participant

    I used the configuration capacitors in series because it is the most gettonata in network diagrams of the IR215x family and I arrived well after such ElettroAmici. A house dispose of several large capacitors, if I remember correctly from 3300 e 6800uF 400v, disassembled by industrial inverters.

    When I have time I modify the schema to a capacitor, I take off the zener 15v leaving from the one near the 2N5551 and placed

    The small toroidal is exactly as I described in my previous post? And it is essential to the diameter of wire 0.1? I have a hard source.

    #6756
    Amilcare
    Keymaster

    No any wire is fine, enough that then we enter all the coils while for the winding which is connected to mostet must have a diameter such as to withstand the current passing through the main transformer otherwise it makes you fuse.

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