What is the max wattage on a port before something will pop? Is it a hard set limit at X watts or is there some head room for things like in-rush current?
24V port .5 amp = 12 watts
48V port .5 amp = 24 watts
48VH port 1.2 amp = 57.6 watts
I was just noticing on my WS-12-250a that's running some Exalt G'2 using 23-24 watts what would happen if they were connected to a standard 48V port? I've never observed the start up current or really seen any peaks over 24 watts while running.
I realize specifying a max number might be a little dangerous but i'm just curious.
Max wattage
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sirhc - Employee
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Re: Max wattage
I would run the Exalts on a 48VH port myself.
Yes, poly fuses are not an exact science.
Yes there is headroom especially for a short in-rush
Do the Exalt radios use all 4 pairs for POE current?
If not then if they only use pins 4,5,7,8 then it does not matter that you are using a 48VH port
My SAF 106 link will not work on a standard 48V port, requires a 48VH port as it uses different pairs than 4,5,7,8
Yes, poly fuses are not an exact science.
Yes there is headroom especially for a short in-rush
Do the Exalt radios use all 4 pairs for POE current?
If not then if they only use pins 4,5,7,8 then it does not matter that you are using a 48VH port
My SAF 106 link will not work on a standard 48V port, requires a 48VH port as it uses different pairs than 4,5,7,8
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adairw - Associate
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Re: Max wattage
Pretty sure the G2 is an 802.3at radio, so yes all four pairs. My question really is. how much before a fuse pops?
if I run a constant 15 or 18 watts at 24 volts would it take it?
what about 30 watts on a 48 volt port? Etc
if I run a constant 15 or 18 watts at 24 volts would it take it?
what about 30 watts on a 48 volt port? Etc
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Dave - Employee
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Re: Max wattage
It is a little tricky to determine when a poly fuse will go open circuit. As a note, we have 2 different fuses in our switch product.
On any port that is 48HV rated, the fuses are actually 0.75 amps. So they will run forever at room temperature allowing 36 watts per power pair at 48 volts, and 18 watts at 24 volts.
On any port that is not 48HV rated, the fuses are actually 0.50 amps. So they will run forever at room temperature allowing 24 watts per power pair at 48 volts, and 12 watts at 24 volts.
However, above numbers are the hold ratings, which mean the fuse will run forever. For ports with the 0.75 Amp fuse, for it to go open circuit at room temperature, it will need to see a 1.5 Amp load for more than 100 seconds, so it has a lot of headroom for normal peak loads we will find in our switch environment.For ports with the 0.50 Amp fuse, for it to go open circuit at room temperature, it will need to see a 1.5 Amp load for more than 100 seconds, so it has a lot of headroom for normal peak loads we will find in our switch environment.
So, in summary, any channel that has a 48HV option, it has a 0.75 amp fuse, all other 24V/48V only ports have a 0.5 Amp fuse, which can run forever at their rate load, and can handle 100% excessive currents for up to 100 seconds before "popping".
That being said, we really did design the circuits to normally only be pulling a steady state of 0.5 amps, with a max continuous of .72 amps, but it should be no problem handling peaks.
Hope this helps.
On any port that is 48HV rated, the fuses are actually 0.75 amps. So they will run forever at room temperature allowing 36 watts per power pair at 48 volts, and 18 watts at 24 volts.
On any port that is not 48HV rated, the fuses are actually 0.50 amps. So they will run forever at room temperature allowing 24 watts per power pair at 48 volts, and 12 watts at 24 volts.
However, above numbers are the hold ratings, which mean the fuse will run forever. For ports with the 0.75 Amp fuse, for it to go open circuit at room temperature, it will need to see a 1.5 Amp load for more than 100 seconds, so it has a lot of headroom for normal peak loads we will find in our switch environment.For ports with the 0.50 Amp fuse, for it to go open circuit at room temperature, it will need to see a 1.5 Amp load for more than 100 seconds, so it has a lot of headroom for normal peak loads we will find in our switch environment.
So, in summary, any channel that has a 48HV option, it has a 0.75 amp fuse, all other 24V/48V only ports have a 0.5 Amp fuse, which can run forever at their rate load, and can handle 100% excessive currents for up to 100 seconds before "popping".
That being said, we really did design the circuits to normally only be pulling a steady state of 0.5 amps, with a max continuous of .72 amps, but it should be no problem handling peaks.
Hope this helps.
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adairw - Associate
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Re: Max wattage
this is excellent info. thank you.
I don't really have any plans of pushing the ports on the switch, but knowing how the switch might react to different situations is very handy. there is a difference of 100 seconds and 100ms (or something like that)
thanks again.
I don't really have any plans of pushing the ports on the switch, but knowing how the switch might react to different situations is very handy. there is a difference of 100 seconds and 100ms (or something like that)
thanks again.
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