Urgent help please!!!!!!

Discussion in 'The Projects Forum' started by aj2310, Jul 5, 2013.

  1. aj2310

    Thread Starter New Member

    Dec 15, 2012
    3
    0
    hi all. i would like some assistance. I have been given this project a month now and haven't made any head way. if you can help me that would be of a great deal.
    the project is to...Build a 10amp 0-180 voltage variable dc supply.

    thank you in advance :)
     
  2. bertus

    Administrator

    Apr 5, 2008
    15,648
    2,347
    Hello,

    I think that it would be undoable.
    A switching regulator will not cover the full range.
    A linear power supply would have to dissipate to much.

    Bertus
     
  3. LDC3

    Active Member

    Apr 27, 2013
    920
    160
    Do you need to supply 10A at 180V? That is some serious power.
    I can't believe you haven't made any progress. What have you considered so far?
    Do you have an outline for your supply?
     
  4. Dodgydave

    Distinguished Member

    Jun 22, 2012
    4,998
    745
    Firstly what is the psu going to be used for, then we can see if an SMPS will do or standard transformer?
     
  5. JohnInTX

    Moderator

    Jun 26, 2012
    2,347
    1,029
    A standard technique to handle this problem is to switch windings in the power transformer windings to provide a secondary voltage just above the desired output voltage. The selection is done by a coarse output voltage range switch or by a microcontroller that switches according to the set output volts. I have supplies that use both techniques.
     
  6. bertus

    Administrator

    Apr 5, 2008
    15,648
    2,347
    Hello,

    @JohnInTX,
    That is true.
    Also an other possibility to reduce the dissipation is pre-regulation using a scr bridge.

    Bertus
     
    JohnInTX likes this.
  7. aj2310

    Thread Starter New Member

    Dec 15, 2012
    3
    0
    It is to power dc motors. Was told not to use diodes to rectify but transistors. Now I have to know what transistors can be used, what transformer and what to use to step up the voltage.
     
  8. Externet

    AAC Fanatic!

    Nov 29, 2005
    761
    57
    180V DC motors do exist for treadmills; and 10 Amperes at 180 V is 1800 W which is 2.4 horsepower, also exist in 180V treadmill mottors.
    To regulate speed, these are controlled by power supplies rectifying 120VAC ; filtering and pulse modulating from 0V to 180V average.

    Study how those variable supplies work to learn how to build one.

    To use transistors instead of diodes to rectify mains is something that can be done. Search this, it may be of help :
    arxiv.org/pdf/1205.4604‎
     
    Last edited: Jul 7, 2013
  9. DickCappels

    Moderator

    Aug 21, 2008
    2,656
    632
    I once designed a 10 amp ±40V DC power supply with .01% noise+regulation. it can be done, but I used an SCR pre-regulator plus a linear output stage. Went through hundreds of dollars worth of exotic transistors before the thing worked properly and was short-proof. Bottom line, unless you have months and thousands of dollars, go out an buy something off the shelf!
     
    absf likes this.
  10. bountyhunter

    Well-Known Member

    Sep 7, 2009
    2,498
    507
    That is not a novice project. Our company (Power Ten) built 2kW power supplies. You can still find some used around the net.
     
  11. bountyhunter

    Well-Known Member

    Sep 7, 2009
    2,498
    507
    Without offending anybody, it is truly absurd to think this project could be assigned to anyone without PS design experience and have a result other than catastrophe. You are basically trying to "re invent" a 2KW offline power supply.

    BUY ONE. And if the price is under $1000, consider it stealing compared to what it will cost to design one.

    http://www.accusrc.com/ccp6796-sore...-supply-0---200v--0---dhp200-10-dhp200-10.htm

    https://www.ntecusa.com/rewrite.cfm...0-P62E-20010/FFC6240B444FF4B6A8EBA3F9817DF9CE
     
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