12 seconds for a fuse to pop??? How is that event a fuse. That sounds pointless.
Josh Luthman Office: 937-552-2340 Direct: 937-552-2343 1100 Wayne St Suite 1337 Troy, OH 45373 On Mon, Mar 21, 2016 at 4:14 PM, Chuck McCown <[email protected]> wrote: > The poe card would not be the cause, it would be the victim. The AP or > wiring would be the cause. > > The polyfuse I am looking at takes 12 seconds to blow. Trying to protect > the power supply and other loads in parallel. > Not sure if that is fast enough to be of great value. > > If one AP shorts out, you don’t want it taking down others that are off > the same power supply. > > *From:* Josh Luthman <[email protected]> > *Sent:* Monday, March 21, 2016 2:07 PM > *To:* [email protected] > *Subject:* Re: [AFMUG] Fuse question > > > Meh just replace the card if it's being troublesome. > > Josh Luthman > Office: 937-552-2340 > Direct: 937-552-2343 > 1100 Wayne St > Suite 1337 > Troy, OH 45373 > On Mar 21, 2016 4:05 PM, "Chuck McCown" <[email protected]> wrote: > >> Well, they have their downside. >> A real fuse will be easier to notice when it is blown. >> A poly fuse just cuts the current way down. >> More of a troubleshooting issue than anything else. >> >> But, if a fuse is blown, then you have to fix the circuit and find a >> replacement fuse. >> I do have LEDs and by unplugging the short circuit cable the LED should >> come back to full brightness. >> >> Just thinking out loud here. Want to make the right choice. >> >> *From:* Josh Luthman <[email protected]> >> *Sent:* Monday, March 21, 2016 2:02 PM >> *To:* [email protected] >> *Subject:* Re: [AFMUG] Fuse question >> >> Cheaper to run a polyfuse...why bother asking??? >> >> >> Josh Luthman >> Office: 937-552-2340 >> Direct: 937-552-2343 >> 1100 Wayne St >> Suite 1337 >> Troy, OH 45373 >> >> On Mon, Mar 21, 2016 at 4:01 PM, Chuck McCown <[email protected]> wrote: >> >>> Still leaning toward the polyfuse. Not a lot of room, fuses and fuse >>> holders are more money. >>> >>> *From:* Bill Prince <[email protected]> >>> *Sent:* Monday, March 21, 2016 1:51 PM >>> *To:* [email protected] >>> *Subject:* Re: [AFMUG] Fuse question >>> >>> Most of ours are now the DIN-mounted double feed that uses the 5x20mm >>> glass fuses. However, we also have a few legacy sites that use the >>> automotive blade fuses. >>> >>> If something new came along, we would use what it uses. >>> >>> bp >>> <part15sbs{at}gmail{dot}com> >>> >>> >>> On 3/21/2016 12:47 PM, Josh Luthman wrote: >>> >>> We already stock 5x20mm fuses so keeping with the same form factor would >>> be nice. Anyone else using those same DIN clip fuse holders have the same. >>> >>> >>> Josh Luthman >>> Office: 937-552-2340 >>> Direct: 937-552-2343 >>> 1100 Wayne St >>> Suite 1337 >>> Troy, OH 45373 >>> >>> On Mon, Mar 21, 2016 at 3:40 PM, Adam Moffett <[email protected]> >>> wrote: >>> >>>> I have no strong opinions sir, but if it's a replaceable fuse I do like >>>> the automotive blades because every gas station has them. >>>> >>>> >>>> On 3/21/2016 2:42 PM, Chuck McCown wrote: >>>> >>>> I am considering adding a fuse to a new version of my rack mount POE >>>> surge suppressors. >>>> >>>> I know many of you like PTC resettable solid state fuses. I don’t >>>> recall ever designing one in to anything. >>>> Maybe I did on a phone device years ago, but that would have been to >>>> satisfy a regulatory agency only. >>>> >>>> Studying up on them I learn that if you have a 1 amp “hold current” the >>>> “always trip” current is 2 amps. >>>> Not like a fuse, which is pretty well guaranteed to trip at any current >>>> over the rating if you wait long enough. >>>> >>>> For a polyfuse, if your load is one amp, you have to have a design >>>> value of greater than 1 amp hold current. >>>> But then it takes double that to actually trip.. >>>> >>>> And then there is leakage current required to keep it in the tripped >>>> condition. >>>> It does not totally break the circuit. >>>> >>>> They are fairly inexpensive compared to glass fuses and fuse holders. >>>> Could do auto blade fuses too. >>>> >>>> Not sure I have the room for anything but a polyfuse though. >>>> >>>> Anyone have strong opinions about this? >>>> >>>> >>>> >>> >>> >>> >> >
