The transformers we use are rated for the 802.3at spec, which is 25.50W per pair at the powered device end, using 48V at the source end and factoring in cable drop along a 100M cable. Note that if you do the division you'll come up with a lower current rating than the magnetics are rated for just because of the cable drop. The manufacturer I use actually has built quite a bit of additional capability in their product - the actual rating is higher - closer to, but not quite as high as what chuck is stating for the ones he uses (which is odd since I though we were using the same magnetics).
It's amazing, though, how many of these cheap PoE injectors use a non-power-rated transformer which is also not rated for extended power range. -forrest On Fri, Feb 13, 2015 at 10:42 AM, Chuck McCown <[email protected]> wrote: > http://www.wbmfg.com/products.cfm?PID=77 > > 1.25 amps per pair or 5 amps for all 8 wires if all on the same polarity. > It will do more but the transformer starts giving off some heat. I think > it unsoldered itself at around 2 amps when I was designing it. > > *From:* TJ Trout <[email protected]> > *Sent:* Friday, February 13, 2015 10:34 AM > *To:* [email protected] > *Subject:* Re: [AFMUG] Site Monitor Gigabit POE Injector Issue, related > to AirFiber 24 > > > What's the rating chuck? > On Feb 13, 2015 9:13 AM, "Chuck McCown" <[email protected]> wrote: > >> I put in the highest current transformers I could find when I >> designed the GigE-APC-POE. >> >> *From:* Erich Kaiser <[email protected]> >> *Sent:* Thursday, February 12, 2015 7:01 PM >> *To:* [email protected] >> *Subject:* Re: [AFMUG] Site Monitor Gigabit POE Injector Issue, related >> to AirFiber 24 >> >> I am going to try a tycon power DC POE tomorrow, see if that will work, >> just need to get it working at this point... Next step would be to run a >> new Cat5. Current Cat5 is Apex9. >> >> Erich Kaiser >> North Central Tower Consulting >> [email protected] >> Office: 630-621-4804 >> Cell: 630-777-9291 >> >> On Thu, Feb 12, 2015 at 7:19 PM, Ken Hohhof <[email protected]> wrote: >> >>> Another (totally hypothetical) thought would be perhaps one of the >>> pairs has a slight DC unbalance causing the DC current not to split >>> equally, thus causing some DC flux in one of the transformers and degrading >>> the pulse characteristics of the transformer. Which could happen if the >>> UBNT injector has transformers with higher saturation specs than the >>> Packetflux injector. >>> >>> *From:* George Skorup (Cyber Broadcasting) <[email protected]> >>> *Sent:* Thursday, February 12, 2015 7:09 PM >>> *To:* [email protected] >>> *Subject:* Re: [AFMUG] Site Monitor Gigabit POE Injector Issue, related >>> to AirFiber 24 >>> >>> Is it an AF24 or 5? The 24 uses 50 watts. The power control relays on >>> the regular and GigE injectors will only handle 1A @ 48VDC. If it's a 24, >>> you're likely over that. The relay contacts are probably fused. >>> >>> The AF specific single-port injector uses a solid-state relay like a >>> SyncInjector and can handle 2A, or more, I forget what Forrest said. >>> >>> That said, if the radio isn't getting enough power, it will be >>> unpredictable. I have seen this happen. Sounds like you've tried the >>> PacketFlux single AF injector and that does it too? Works fine with the >>> UBNT brick? I have no idea. >>> >>> On 2/12/2015 6:52 PM, Erich Kaiser wrote: >>> >>> Guys this is not my first rodeo, This is the new Gigabit 8 Port Injector >>> and I have also tried the Packetflux Airfiber Injector, same issue, switch >>> to stock UBNT POE and it works fine. This is an all DC site, with separate >>> DC to DC converters and everything is fused..... >>> >>> See POE directions direct from Packetflux >>> >>> [image: Inline image 1] >>> >>> Erich Kaiser >>> North Central Tower Consulting >>> [email protected] >>> Office: 630-621-4804 >>> Cell: 630-777-9291 >>> >>> On Thu, Feb 12, 2015 at 6:45 PM, Bill Prince <[email protected]> >>> wrote: >>> >>>> It should not work with a regular POE injector. 50 watts is too much >>>> current for 4 pins; you need to supply power on all 8 pins. And that, in >>>> turn, requires transformers to isolate the data lines. >>>> >>>> So I would not expect it to work at all with a vanilla POE. Well, >>>> maybe it might work for a little while, and it would probably only do >>>> 100baseT. Then the 4/5 & 7/8 pins will fry. >>>> >>>> bp >>>> <part15sbs{at}gmail{dot}com> >>>> >>>> >>>> On 2/12/2015 4:20 PM, Erich Kaiser wrote: >>>> >>>> Anyone else seen any issues with the Airfiber Module or running the >>>> Airfiber through the Gigabit POE Injector. I am seeing an issue with TX >>>> data, RX works fine, getting full bandwidth. TX I get about 2Mbps. Hooked >>>> up to Regular POE and everything is fine, any ideas? >>>> >>>> >>>> Erich Kaiser >>>> North Central Tower Consulting >>>> [email protected] >>>> Office: 630-621-4804 >>>> Cell: 630-777-9291 >>>> >>>> >>>> >>> >>> >>> >> >
