What is The Fuse I Need To Install

Discussion in 'Homework Help' started by hitmen, Nov 17, 2013.

  1. hitmen

    Thread Starter Active Member

    Sep 21, 2008
    159
    0
    Hi guys,

    This isnt exactly homework. What is the fuse rating in which I need to install? Why is the maximum voltage less than the rated voltage range? Why is there a negative sign?

    AC:
    Rated volt: 100V to 240V, 50/60 Hz
    Max volt: 90V to 264V, 50/60Hz
    DC:
    Rated voltage: -48V to -60V
    Max range: -36V to -72V (why is there a negative signfor DC but not AC?)

    Power consumption: <455W
     
    Last edited: Nov 17, 2013
  2. MrChips

    Moderator

    Oct 2, 2009
    12,442
    3,361
    Don't know.
    You have to tell us what is the device, tool, appliance?
    We can't see it from here.
     
  3. hitmen

    Thread Starter Active Member

    Sep 21, 2008
    159
    0
    It is a switch fom the data centre. Is it necessary to know the appliance?
     
  4. shteii01

    AAC Fanatic!

    Feb 19, 2010
    3,392
    497
    If you look at power supply for computer, you will notice that you put in
    AC: 100-240 volts at 50/60 Hz.

    What you get out is variety of DC voltages (I am looking at old Apple LCII psu):
    +5 volts
    -5 volts
    +12 volts

    So. Putting in AC voltages and getting out negative DC voltages is very common, particularly in computer/IT industry.
     
  5. hitmen

    Thread Starter Active Member

    Sep 21, 2008
    159
    0
    to calculate my current for the fuse, do I use 455/90 or 455/100 ?? I am confused.
     
  6. shteii01

    AAC Fanatic!

    Feb 19, 2010
    3,392
    497
    Are you putting fuse on AC side or DC side?

    Also. Are you sure fuse is not built in already?
     
  7. hitmen

    Thread Starter Active Member

    Sep 21, 2008
    159
    0
    It is on the AC side. I am calculating the current this equipment consumes as well as some other equipment. Assume no fuse installed.
     
  8. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,548
    2,373
    You need a fuse rated at least at the supply voltage and at the current demand of the system, allow for minimum 10% - 20% over this, if it is to protect solid state equipment directly, fast blow is usually used, if there is any kind of inrush, power supplies or large transformers, then slo-blow is needed.
    Max.
     
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