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

 

Don't know.
You have to tell us what is the device, tool, appliance?
We can't see it from here.

 

It is a switch fom the data centre. Is it necessary to know the appliance?

 

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

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.

 

to calculate my current for the fuse, do I use 455/90 or 455/100 ?? I am confused.

 

to calculate my current for the fuse, do I use 455/90 or 455/100 ?? I am confused.

Are you putting fuse on AC side or DC side?

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

 

It is on the AC side. I am calculating the current this equipment consumes as well as some other equipment. Assume no fuse installed.

 

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.