Simple Bench Power Supply 10A

Discussion in 'The Projects Forum' started by ortiko, Oct 21, 2014.

  1. ortiko

    Thread Starter Member

    Oct 21, 2014
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  2. ScottWang

    Moderator

    Aug 23, 2012
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    If you using this circuit, the power transistor are 2N3055, for the power consumption issue, so you better using 4 pcs of 2n3055, at least 3 pcs, and each 2n3055 needs to in series with a 0.2Ω/10W resistor.
     
  3. ortiko

    Thread Starter Member

    Oct 21, 2014
    64
    1
    No images...? Sorry
    Maybe a moderator can erase the above post please

    After a conversation I had with colleague Andreas about it...

    pcb.jpg

    10606485_525123250924472_2137030186550613613_n.jpg

    10320425_525123357591128_4830321213342133084_n.jpg

    10609577_525123377591126_3299348537425137009_n.jpg

    1489126_525123397591124_5217686867022579283_n.jpg

    To be continued...
     
    Last edited: Oct 21, 2014
  4. ScottWang

    Moderator

    Aug 23, 2012
    4,853
    767
    Your attachments are wrong.
     
  5. ortiko

    Thread Starter Member

    Oct 21, 2014
    64
    1
    Bath time

    10410547_525123757591088_8351452807682665078_n.jpg
    Enough

    63725_525123807591083_7442641732179557926_n.jpg

    Second bath with
    ferric

    10462648_525123907591073_2736289206230154110_n.jpg
     
  6. ortiko

    Thread Starter Member

    Oct 21, 2014
    64
    1

    I have replaced the 2n3055 with MJ15003
    It is far better as i know
     
  7. ortiko

    Thread Starter Member

    Oct 21, 2014
    64
    1
    And the resaults are very good !!!


    1653977_525124080924389_1561720960081989537_n.jpg

    polishing :)

    10406794_525123970924400_6135077443849634727_n.jpg
    Electroprojects
    10701958_525126174257513_7281461615326927082_n.jpg

    Drilling it...

    10384763_525126067590857_4162893018082357535_n.jpg

    Holes readyto insert parts
    1965047_525204430916354_128054780351206937_n.jpg
     
  8. ortiko

    Thread Starter Member

    Oct 21, 2014
    64
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    Mounting the transistors and parts at pcb

    10154417_525126780924119_6194540459509658784_n.jpg

    Ready
    1013249_525126807590783_8797193021566221081_n.jpg



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  9. ortiko

    Thread Starter Member

    Oct 21, 2014
    64
    1
    Time to gather all parts and connect them

    Transformer:
    1779230_525130244257106_6669037837783224821_n.jpg
    1779313_525127387590725_1453750410713502859_n.jpg
     
  10. ortiko

    Thread Starter Member

    Oct 21, 2014
    64
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    Something i haven't done yet and must be done is to make the Transformer from 30-0-30 8A to 0-30 8A
    Need to parallel the secondary so i can drain all amperage from 0-30

    Any suggestions will be appreciated.
     
  11. R!f@@

    AAC Fanatic!

    Apr 2, 2009
    8,753
    760
    U can if you can isolate the center tap.
    CT secondary are connected as follows.
    30-0-30 --> Start A(30V)-End A joined with start B (0V)-End B (30V).
    A and B are two secondary windings.
    Disconnect End A and Start B ( which is Center tap )
    Connect Start A and Start B together
    Connect End A and End B together.

    After you disconnect center tap you will have isolated secondary A and B windings. You will get 30VAC on each windings.
    After paralleling them if you measure 30VAC on the secondary winding you are good to go.
    Mind you if one winding can handle 8A you can draw max of 16Amps by paralleling them
     
  12. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    By the way for huge currents, the smoothing cap needs to be 10,000uf or more.

    And the Power should be taken directly from the capacitor terminals.
    Not one from cap and one from bridge as shown in ur picture

    PS. You should add fuses in primary and secondary. You are dealing with high currents
     
  13. ortiko

    Thread Starter Member

    Oct 21, 2014
    64
    1
    Is this what i must do ?
    It is real simple i think but haven't opened a transformer before

    tr.JPG
     
  14. tom_s

    Member

    Jun 27, 2014
    285
    333
    my bench supply is similiar to this using lm317/337 mj15003/15004's

    R!f@@ 's comment about fuses should be noted (read as a requirement - common sense)

    edit: no need to 'open' the transformer, from the look of the picture, the two windings have already been soldered together on the 20v secondary side (centre wiring - 2 wires twisted and soldered) just need to break that connection and parallel up as per your diagram.
     
  15. ortiko

    Thread Starter Member

    Oct 21, 2014
    64
    1
    Fuse are in schedule from the beginning of this project :)
    They will be added at the chassis when it will be ready... (pics of it are coming soon)

    I will give it a shot with secondary of transformer this evening
    Thanks for the advice
     
  16. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    As said, you do not need to dismantle the whole TX.
    The center tap is accessible easily. Just use the iron and untwist the secondary with pliers and you can connect as per ur diagram.
     
  17. ortiko

    Thread Starter Member

    Oct 21, 2014
    64
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    This is the old pc case that will be used/modified

    10702238_525127484257382_5981183705536203891_n.jpg

    1512363_525127457590718_1109677534023856376_n.jpg
    New frontage
    10606213_525127520924045_5466756736343257219_n.jpg
    New frontage cuted...

    10516632_525127644257366_2874646674818114449_n.jpg


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    drilled for the case..

    397491_525127687590695_4609253292069646141_n.jpg
     
  18. ortiko

    Thread Starter Member

    Oct 21, 2014
    64
    1
    I was thinking using the pc case button and make a little very very simple circuit for electronic switch with relay.
    This is what i found with a quick search
    http://www.electronics-tutorials.ws/blog/relay-switch-circuit.html

    relay.JPG

    This needs extra power supply for vin :(

    If anyone can suggest a very simple one it will be nice to share with me.
     
  19. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    Power Supplies use toggle switches.
    Safer and better.
    I wonder why you need to use a relay.

    Using that circuit requires the power applied to TX always. If this is not a problem for you, you can use a resistor of appropriate value. Power can be taken from the capacitor.
    Another option is to use a smaller Tx as the standby PSU
     
  20. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    760
    Mind you a PC uses push button switches which are temporary.
    That circuit requires a toggle switch.
    A PC power button will just on the relay when pressed and switch off the relay when the button is released.

    So I believe you are better off with a power toggle switch
     
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