The world of model and hobby engineering

Subscribe

The Modelling Hub Logo

The world of model and hobby engineering

Subscribe
Buy Latest Issue

Forums

Help

Register

Log in

power supply

Advert
New Replies
Report Bug
Help/FAQs

power supply

Home › Forums › Electronics in the Workshop › power supply

Viewing 8 posts - 1 through 8 (of 8 total)
  • Author
    Posts
  • 19 August 2016 at 12:04 #251474
    Gordon W
    Participant
      @gordonw

      This will be a simple question for a lot of you– I have a couple of ex-computer power supply "boxes". Label states +12 V 12amp max, -12V 1amp max. Max continuous DC power 200W. If I use this to drive a DC motor do I connect to + and – and then can use the full 12 amps if need be ?, Or connect to + and ground ( the case )? Could I use two supplies in parallel and get 24 Amps ? OK that's two questions.

      Advert
      19 August 2016 at 12:04 #31849
      Gordon W
      Participant
        @gordonw
        19 August 2016 at 12:24 #251479
        Martin Kyte
        Participant
          @martinkyte99762

          You have in each box 2 supplies one at +12V @ 12A and one at -12V @ 1A.

          To use the +12V connect between +12V and 0V. Not a good idea to connect the two boxes in parallel.

          You may have to fiddle about a bit. Computer supplies are usually power managed from the mother board or at least some remote on/off switching device.

          regards Martin

          19 August 2016 at 12:49 #251488
          Neil Wyatt
          Moderator
            @neilwyatt

            There will be a wire (green or purple from memory) that has to be shorted to ground to get it to work. Check the net.

            Some PSUs used to require a modest load on the +5v line to allow the higher voltages to work as well. Not sure if this still applies.

            A bit of filtering between output and load might make it live longer if using with a motor.

            Neil

            19 August 2016 at 14:16 #251507
            Gordon W
            Participant
              @gordonw

              Thanks for the quick replies. Have been looking on the net and more or less what you are saying, can't think why I never tried the net first ! Seems green wire is the start wire and may need a push switch, but will have to try it and see. What sort of filter might be needed ? Will have to get going with the old meter. Not sure how old these are but not modern. I can see what looks like a choke or small toroidal transformer inside.

              19 August 2016 at 14:28 #251508
              Ed Duffner
              Participant
                @edduffner79357

                With a negative 12 volts I think that's an old AT PSU as opposed to the later ATX versions.

                Connect the green wire to any black wire to make the PSU work, needs to be a constant connection, not just a push-to-connect.

                Ed.

                19 August 2016 at 14:30 #251510
                Martin Kyte
                Participant
                  @martinkyte99762

                  It's undoubtedly a switch mode supply and will have high frequency chokes and toroids.

                  Martin

                  13 June 2019 at 09:01 #414029
                  Speedy Builder5
                  Participant
                    @speedybuilder5

                    Just a "heads up" If you like a bit of electronics dabbling, it may be time to grab hold of a few desk top computer power supplies. A lot of the market is going / gone to laptops and old desktop computers are two a penny when out of date. Grab a few before its too late ??

                  • Author
                    Posts
                  Viewing 8 posts - 1 through 8 (of 8 total)
                  • Please log in to reply to this topic. Registering is free and easy using the links on the menu at the top of this page.

                  Latest Replies
                  Report Bug
                  Code of Conduct
                  Help & FAQs
                  Advert

                  Latest Replies

                  Home › Forums › Electronics in the Workshop › Topics

                  Viewing 25 topics - 1 through 25 (of 25 total)
                  Viewing 25 topics - 1 through 25 (of 25 total)

                  View full reply list.

                  Advert

                  Latest Issue

                  Subscribe
                  Buy Latest/Back Issues

                  Newsletter Sign-up

                  Latest Replies