100W smps auto trip/shutdown

Discussion in 'General Electronics Chat' started by user0n9, Apr 26, 2010.

  1. user0n9

    Thread Starter New Member

    Jul 3, 2008
    4
    0
    Hi people,

    I have two 100W single output switching power supply:

    1) HF100-SF-24
    Setup, Rise Time, Hold Up Time: UNKNOWN, 50ms, 20ms at full load
    Inrush current: cold start, 40A/230Vac

    For more information please refer: http://www.hengfu.com/en catalog PDF/Single/HF100W-SF.pdf

    2) S-100-24
    Setup, Rise Time, Hold Up Time: 200ms, 80ms, 24ms at full load
    Inrush current: cold start, 54A/230Vac

    For more information please refer: http://www.meanwell.com/search/s-100f/S-100F-spec.pdf


    Previously HF-100-SF-24 is used in my application and everything goes perfectly.
    But when S-100-24 is used an issue occur.

    S-100-24 will trip/shutdown when machine is switch on and it output voltage drop to 8V instead of 24V.

    May I know the source problem behind this? Is it because of S-100-24 Rise Time, Inrush Current or its hardware circuit design problem?

    Please advice.

    Best Regards.
     
  2. rjenkins

    AAC Fanatic!

    Nov 6, 2005
    1,015
    69
    What loads (current ratings) are you using and which are switched?

    You say the PSU trips when 'the machine' is switched on - are you switching the output of the PSU, or is part of the load continuous and part switched?
     
  3. user0n9

    Thread Starter New Member

    Jul 3, 2008
    4
    0
    hi rjenkins,

    i could not measure the current rating due to lack of equipment.
    the smps is connected to the load (2 device in parallel).
    max continuous current of each the load is 6A and inrush is 12A

    i switch on the main supply (230Vac) to run the machine.

    After replace the smps again to NES-150-24 (http://www.meanwell.com/search/nes-150/nes-150-spec.pdf) everything works fine again.
    so I can assume S-100-24 output is not sufficient for my application?

    please advice.. thanks
     
  4. eblc1388

    Senior Member

    Nov 28, 2008
    1,542
    102
    When cold start against heavy output loading, the power supply wrongly thinks there is a short circuit on its output so goes into overload protection mode.

    This will not happen if the power supply is switched on first and then load applied.

    While your running load stays within the normal output capacity of the supply but possibility is that the inrush current of your loading during startup have exceeded the current limit of the power supply output.

    Whether this is a fault or feature will depends on your application.
     
  5. user0n9

    Thread Starter New Member

    Jul 3, 2008
    4
    0
    hi eblc1388,

    I think that should be the root cause of the issue.
    Thanks for your explanation.

    by the way, do you face the same problem before?

    Regards
     
  6. eblc1388

    Senior Member

    Nov 28, 2008
    1,542
    102
    Something not quite right here. The output power don't add up to your load requirement.

    The max. current from the supply is only 4.5A and you have connected two devices to its output each drawing inrush current of 12A?

    [​IMG]
     
  7. user0n9

    Thread Starter New Member

    Jul 3, 2008
    4
    0
    Both 6A and 12A are the MAX value stated in the manual.
     
Loading...