The PSU & Pixel Dilema

Discussion in 'The Family Room' started by Beacy, Dec 7, 2014.

  1. Beacy

    Beacy It's so much better on the dark side

    Joined:
    Jun 10, 2010
    Messages:
    466
    Likes Received:
    0
    Location:
    Beaconsfield
    Well adding extra pixel elements was always going to add to the issues but I now find myself in the situation that with all the injection pionts and the need to have PSU's close to controllers I have had to add PSU's however this has resulted on continual tripping of the RCD switch ..... always on the last PSU/power board.... does not matter which order I power up in it is always the last switch. (they are turned on in sections of 3-4 baords at a time)


    Consequently I have had to reduce the number of PSU's as they are clearly sucking too much power. (they are split acros 3 seperate zones) I have isolated evry PSU and non of them trip it on their own so I can only assume that all are in good working order and there are no earth leaks.


    Would be interested in any suggestionas as to how to slove the issue as I still have to power up the mega tree ...6 more PSU's
     
  2. ԆцряєсϮ

    ԆцряєсϮ Senior Elf

    Joined:
    Dec 24, 2011
    Messages:
    502
    Likes Received:
    1
    Location:
    Botanic Ridge
    Find Me On:
    Trouble with cheaper PSU's is not so much the current draw but the lack of power factor
    correction.
    Especially when you start using high numbers of them
    You may have to incorporate some power factor correction.
    I thing quang fung had a fairly indepth post explaining the ins and outs of PFC on PSU's somewhere.
    The better quality PSU's usually have PFC built in, most of the Chinese ones dont.
     
  3. David_AVD

    David_AVD Good news, everyone!

    Joined:
    Jun 12, 2010
    Messages:
    3,346
    Likes Received:
    22
    Location:
    Victoria Point (Brisbane)
    It could be a case of accumulative earth leakage; each PSU on it's own is not enough to trip the RCD but combined (with you other household items) they are just over the limit.

    I have separate MCB/RCD breakers for each circuit in my house. This means that each one is only dealing with the leakage on just the items for that circuit.

    The upgrade to separate MCB/RCD breakers was very straightforward on my house and not all that expensive. If you did something like that and split the PSU load over several circuits that may solve your issue.
     
  4. fasteddy

    fasteddy I have C.L.A.P Global Moderator Generous Elf

    Joined:
    Apr 26, 2010
    Messages:
    6,471
    Likes Received:
    16
    Location:
    Albion Park NSW
    Find Me On:
    I would tend to think this is what is happening as well especially if your power system has a shared RCD for multiple power circuits as all cheap switch mode power supplies will leak some residual current.
     
  5. David_AVD

    David_AVD Good news, everyone!

    Joined:
    Jun 12, 2010
    Messages:
    3,346
    Likes Received:
    22
    Location:
    Victoria Point (Brisbane)
    Upgrading to individual MCB/RCD combo units also makes tracking down what appliance is doing the tripping and limits the power outage to just that circuit.
     
  6. fasteddy

    fasteddy I have C.L.A.P Global Moderator Generous Elf

    Joined:
    Apr 26, 2010
    Messages:
    6,471
    Likes Received:
    16
    Location:
    Albion Park NSW
    Find Me On:
    This is what i did when we built our house, it came with a shared RCD, so now each circuit has its own RCD/MCB and its much better like on the weekend with all the rain i had a trip but only lost the one circuit instead of the whole house.
     
  7. multicast

    multicast Senior Elf Generous Elf

    Joined:
    Jul 13, 2013
    Messages:
    711
    Likes Received:
    6
    RCD tripping isn't a Power factor issue.


    Switch mode power supplies by their very nature "switch" the AC on and off rapidly, and are therefore electrically noisy. Noisy enough that if you did'n do something about it, you'd cause all sorts of problems. SMPS's therefore have 'filters' on their inputs to prevent that 'noise' getting out of the power supply back onto the AC mains.. that noise has to go somewhere.. guess where it goes, it goes into your Earth connection.. ( there are generally a pair of Capacitors, one from Phase to Earth, and one from Neutral to Earth, that are the filter ). Depending on your ps, the amount of noise could amount to a few mA, into the Earth. Get enough PSU's on the same supply and you'll likely exceed the limit of your RCD..


    Power Factor issues will likely trip circuit breakers unexpectantly, ( well before you think you had enough load ) and is a different topic.


    Fixes;


    (a) Get better power supplies.
    (b) Spread the Power Supplies across multiple circuits each with their own RCD
     
  8. gerry

    gerry Senior Elf

    Joined:
    Dec 19, 2012
    Messages:
    793
    Likes Received:
    1
    Location:
    Surrey Hills,Melbourne
    I have been to Beacys place this week (and was disappointed that the lights were not fully working :( ).

    It looks quite new and therefore I would have thought that his place would have had multiple MCB's as mine has (I had to google that to see the picture BTW). In which case Beacy, do you have the connections to the PSU's coming off different 5 A switches (eg say one from each garage) such that they automatically feed off diff MCB's ?
    this is what I have done , even though the number of lights I have is a pittance compared to yours.
    Your first post did say separated into 3 though..
     
  9. OP
    OP
    Beacy

    Beacy It's so much better on the dark side

    Joined:
    Jun 10, 2010
    Messages:
    466
    Likes Received:
    0
    Location:
    Beaconsfield
    Soprry the lights weren't working properly the bigger the show the bigger the issues all going well should be up and running this w/e
     

Share This Page