Switching power supplies - linking in series

Discussion in 'General Electronics Chat' started by raychar, Jan 15, 2012.

  1. raychar

    Thread Starter Member

    Nov 8, 2011
    Hello, everybody

    Is it possible to put two 38V 360W switching power supplies in series manner to achieve 76V output voltage?

    The power supplies are going to be bought in existing market. I don't
    want to modify the internal constructions. Can I build some external
    circuits to link them up to achieve this purpose.

  2. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
    Are the outputs isolated from ground? Use a DMM, when power is off on both, check for resistance between the - and a chassis screw, if there is continuity, the outputs aren't isolated. Do the same between the + and a chassis screw.

    Another way is with both of them on, measure voltage from the - of one to the + of the other, if it reads 38V, they aren't isolated, if it reads 0V, there's a chance it might work.

    What brand/make/model are the supplies?
  3. crutschow


    Mar 14, 2008
    If you do connect them in series, you should add a rectifier across each output (cathode to plus) so that if one supply is off the other can't drive current though it which could cause damage, depending upon its design. The rectifier will bypass this current.
  4. raychar

    Thread Starter Member

    Nov 8, 2011
    In the worst case, if they are not isolated, can I do the followings:

    -Putting two power supplies into a seperated metal housing, however, insulating material is put between power supplies' case and the metal housing.
    -Only connecting Live and Earth to these two suppliers with Ground disconnected from them.
    -Ground is connected to the enclosing metal housing instead.

    Attached is picture of the power supply that I intend to purchase.