Hi,

Does anyone know of a PoE injector that doesn't let the magic smoke
out if the power glitches? Local community broadband lost four more
yesterday that's on top of the 40 odd in the previous six months.
That's a significant amount of money at £20 each...

They have used Fairway Electronic Co. Ltd VE20C-48A and SL Power
Electronics PW182RE4800F02 with negliable difference between 'em.
These are (supposed to be...) IEEE 802.3at (note t not f(*)) devices,
IEC mains in, ethernet and ethernet + (proper) PoE out.

(*) That is PoE+ or PoE Plus which can deliver up to 25 W to the
remote device rather than the 15 W of IEEE 802.3.af.

--
Cheers
Dave.

Dave Liquorice wrote:
Hi,

Does anyone know of a PoE injector that doesn't let the magic smoke
out if the power glitches? Local community broadband lost four more
yesterday that's on top of the 40 odd in the previous six months.
That's a significant amount of money at £20 each...

They have used Fairway Electronic Co. Ltd VE20C-48A and SL Power
Electronics PW182RE4800F02 with negliable difference between 'em.
These are (supposed to be...) IEEE 802.3at (note t not f(*)) devices,
IEC mains in, ethernet and ethernet + (proper) PoE out.

(*) That is PoE+ or PoE Plus which can deliver up to 25 W to the
remote device rather than the 15 W of IEEE 802.3.af.


UPS time?

On Thu, 13 Feb 2014 13:14:01 +0000, Capitol wrote:

Does anyone know of a PoE injector that doesn't let the magic
smoke
out if the power glitches?

UPS time?

Most small and affordable UPS's are offline and normally the
downstream devices connected directly to the incoming mains. Glitches
can still reach the connected kit, indeed a couple of PoEs that died
the other week were "behind" such a UPS.

With an online UPS the downstream kit is powered by the invertor all
the time not just when the supply power is off/too low.

I've yet to see a dead example but the smoke comes out the RJ45 end
so I suspect the mains disturbance is causing drops/surges in the 48
V and the controlling circuitry for that dies big time.

--
Cheers
Dave.

In article o.uk, Dave
Liquorice scribeth thus
Hi,

Does anyone know of a PoE injector that doesn't let the magic smoke
out if the power glitches? Local community broadband lost four more
yesterday that's on top of the 40 odd in the previous six months.
That's a significant amount of money at £20 each...

They have used Fairway Electronic Co. Ltd VE20C-48A and SL Power
Electronics PW182RE4800F02 with negliable difference between 'em.
These are (supposed to be...) IEEE 802.3at (note t not f(*)) devices,
IEC mains in, ethernet and ethernet + (proper) PoE out.

(*) That is PoE+ or PoE Plus which can deliver up to 25 W to the
remote device rather than the 15 W of IEEE 802.3.af.

--
Cheers
Dave.



If its a 24/48 volt POE system Dave some makers do DC ones where you
could run the POE's at the headend off 12 volt batteries 2/4 series
connected.

We did that with some Ubiquity equipment's saved a lot of bother with
UPS's in places that are a bit rough for 'em...


http://www.wifi-stock.co.uk/details/..._injector.html
--
Tony Sayer

On Thu, 13 Feb 2014 20:44:31 +0000, tony sayer wrote:

If its a 24/48 volt POE system Dave some makers do DC ones where you
could run the POE's at the headend off 12 volt batteries 2/4 series
connected.

48 V but I'm under the impression that 802.3at is active not passive.
ie the full 48 V 25 W supply is not applied until the two ends have
had a little chat and agreed about what is required. I don't know if
just feeding a (current limited) 48 V up the right pairs would "just
work".

UPS and keeping things up for a short time is nice but not essential.
If the power has gone in an area most users won't have power for
their end of the wireless link so won't notice that the AP is down as
well. B-)

It's the fact that the injectors leak the magic smoke when the mains
has a minor whoopsie that is the real problem. It's geographic as
well, one village has virtually no problems, the town and a couple of
other villages do. Everywhere is fed via various 11 kV lines from the
same 33 kV substation. I wondering if there is a fundemental problem
in/around the 33 kV substation or 11 kV switching.

We did that with some Ubiquity equipment's saved a lot of bother with
UPS's in places that are a bit rough for 'em...

From googling about the other day it seems that Ubiquity kit tends to
be a bit non-standard. The kit in question is Proxim 5054 and the
like.

http://www.wifi-stock.co.uk/details/..._injector.html

That looks passive to me and most places only have two or three bits
of PoE kit.

--
Cheers
Dave.

Dave Liquorice wrote:
On Thu, 13 Feb 2014 20:44:31 +0000, tony sayer wrote:

If its a 24/48 volt POE system Dave some makers do DC ones where you
could run the POE's at the headend off 12 volt batteries 2/4 series
connected.

48 V but I'm under the impression that 802.3at is active not passive.
ie the full 48 V 25 W supply is not applied until the two ends have
had a little chat and agreed about what is required. I don't know if
just feeding a (current limited) 48 V up the right pairs would "just
work".

UPS and keeping things up for a short time is nice but not essential.
If the power has gone in an area most users won't have power for
their end of the wireless link so won't notice that the AP is down as
well. B-)

It's the fact that the injectors leak the magic smoke when the mains
has a minor whoopsie that is the real problem. It's geographic as
well, one village has virtually no problems, the town and a couple of
other villages do. Everywhere is fed via various 11 kV lines from the
same 33 kV substation. I wondering if there is a fundemental problem
in/around the 33 kV substation or 11 kV switching.

We did that with some Ubiquity equipment's saved a lot of bother with
UPS's in places that are a bit rough for 'em...

From googling about the other day it seems that Ubiquity kit tends to
be a bit non-standard. The kit in question is Proxim 5054 and the
like.

http://www.wifi-stock.co.uk/details/..._injector.html

That looks passive to me and most places only have two or three bits
of PoE kit.


I'd put a transient detector with logging capability on the supply to
see what is happening. Are you using surge suppression?

In article o.uk, Dave
Liquorice scribeth thus
On Thu, 13 Feb 2014 20:44:31 +0000, tony sayer wrote:

If its a 24/48 volt POE system Dave some makers do DC ones where you
could run the POE's at the headend off 12 volt batteries 2/4 series
connected.

48 V but I'm under the impression that 802.3at is active not passive.
ie the full 48 V 25 W supply is not applied until the two ends have
had a little chat and agreed about what is required. I don't know if
just feeding a (current limited) 48 V up the right pairs would "just
work".


48 volts and 25 watts?. Seems a lot unless its feeding more than the one
unit!.

The max power permitted in 5.8 Ghz band C is 4 watts effective radiated
and theres going the be quite a bit of aerial gain in that sort of
unit..

UPS and keeping things up for a short time is nice but not essential.
If the power has gone in an area most users won't have power for
their end of the wireless link so won't notice that the AP is down as
well. B-)

Indeed...


It's the fact that the injectors leak the magic smoke when the mains
has a minor whoopsie that is the real problem. It's geographic as
well, one village has virtually no problems, the town and a couple of
other villages do. Everywhere is fed via various 11 kV lines from the
same 33 kV substation. I wondering if there is a fundemental problem
in/around the 33 kV substation or 11 kV switching.


Does seem rather poor. Have you/they sent any units back to the makers
for comment or inspection at all?..

We did that with some Ubiquity equipment's saved a lot of bother with
UPS's in places that are a bit rough for 'em...

From googling about the other day it seems that Ubiquity kit tends to
be a bit non-standard. The kit in question is Proxim 5054 and the
like.


Dunno thats non standard..

http://www.wifi-stock.co.uk/details/..._injector.html

That looks passive to me and most places only have two or three bits
of PoE kit.

Well in that instance it's providing for a few more but its run of a
batteries and a charger method ...
--
Tony Sayer

On Sat, 15 Feb 2014 17:28:33 +0000, tony sayer wrote:

48 volts and 25 watts?. Seems a lot unless its feeding more than the one
unit!.

The max power permitted in 5.8 Ghz band C is 4 watts effective radiated
and theres going the be quite a bit of aerial gain in that sort of
unit..

48 V 25 W is the spec for 802.3at (PoE+). There is more than just the
radio in the unit but all the other electronics for an AP, Bridge, or
Customer unit. The Proxim MP.11 5054 units are rated at "20 W max"
and no mention that I have found of 802.3at or af. The smaller
customer unit 5012 *does* mention 802.3af (top whack 15 W).

Does seem rather poor. Have you/they sent any units back to the makers
for comment or inspection at all?..

Not that I am aware of, I suspect a certain amount of "it's not worth
it for a 20 quid PSU, which if it was just one a year would be
acceptable. 40 in six months is another story. Unfortunately the old
busted ones have gone in the bin...

--
Cheers
Dave.

In article o.uk, Dave
Liquorice scribeth thus
On Sat, 15 Feb 2014 17:28:33 +0000, tony sayer wrote:

48 volts and 25 watts?. Seems a lot unless its feeding more than the one
unit!.

The max power permitted in 5.8 Ghz band C is 4 watts effective radiated
and theres going the be quite a bit of aerial gain in that sort of
unit..

48 V 25 W is the spec for 802.3at (PoE+). There is more than just the
radio in the unit but all the other electronics for an AP, Bridge, or
Customer unit. The Proxim MP.11 5054 units are rated at "20 W max"
and no mention that I have found of 802.3at or af. The smaller
customer unit 5012 *does* mention 802.3af (top whack 15 W).

Don't think that Ubiquity or the older Egenous units ever got warm;!..


Does seem rather poor. Have you/they sent any units back to the makers
for comment or inspection at all?..

Not that I am aware of, I suspect a certain amount of "it's not worth
it for a 20 quid PSU, which if it was just one a year would be
acceptable. 40 in six months is another story. Unfortunately the old
busted ones have gone in the bin...


I don't remember having a duff one apart from one that got walloped by
lightning the other week. There wasn't anything left of the CAT 5 cable
so what chance did the rest of it have;!..

--
Tony Sayer

In article o.uk,
"Dave Liquorice" writes:
On Thu, 13 Feb 2014 20:44:31 +0000, tony sayer wrote:

If its a 24/48 volt POE system Dave some makers do DC ones where you
could run the POE's at the headend off 12 volt batteries 2/4 series
connected.

48 V but I'm under the impression that 802.3at is active not passive.
ie the full 48 V 25 W supply is not applied until the two ends have
had a little chat and agreed about what is required. I don't know if
just feeding a (current limited) 48 V up the right pairs would "just
work".

The PW182RE4800F02
(http://www.proxim.com/downloads/prod...N_69823_A4.pdf)
claims to be 19W max, and doesn't claim to conform to any PoE
standard (specifically says it doesn't conform to IEEE802.3af).

Looks like it just applies power direct to pairs 2 and 3. If
that's not the case, it doesn't say what protocol it uses to
negotiate.

What kit is on the other end consuming the power?

It's the fact that the injectors leak the magic smoke when the mains
has a minor whoopsie that is the real problem. It's geographic as
well, one village has virtually no problems, the town and a couple of
other villages do. Everywhere is fed via various 11 kV lines from the
same 33 kV substation. I wondering if there is a fundemental problem
in/around the 33 kV substation or 11 kV switching.

Or a spike on the LV phase due to damaged 3-phase neutral?

We did that with some Ubiquity equipment's saved a lot of bother with
UPS's in places that are a bit rough for 'em...

From googling about the other day it seems that Ubiquity kit tends to
be a bit non-standard. The kit in question is Proxim 5054 and the
like.

http://www.wifi-stock.co.uk/details/..._injector.html

That looks passive to me and most places only have two or three bits
of PoE kit.


--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On Sat, 15 Feb 2014 18:54:02 +0000 (UTC), Andrew Gabriel wrote:

The PW182RE4800F02
(http://www.proxim.com/downloads/prod...N_69823_A4.pdf)
claims to be 19W max, and doesn't claim to conform to any PoE
standard (specifically says it doesn't conform to IEEE802.3af).

Looks like it just applies power direct to pairs 2 and 3. If
that's not the case, it doesn't say what protocol it uses to
negotiate.

What kit is on the other end consuming the power?

Varies but Proxim MP.11 5054 which states "20 W max". A 19 W max
supply is sailing a bit close to the wind IMHO... Bit of a power
glitch the unit pulls more power just when the volts is low so up
goes the current a phizt...

It's geographic as well, one village has virtually no problems,
the
town and a couple of other villages do. Everywhere is fed via
various
11 kV lines from the same 33 kV substation. I wondering if there
is a
fundemental problem in/around the 33 kV substation or 11 kV
switching.

Or a spike on the LV phase due to damaged 3-phase neutral?

Now there's an idea. From what I've heard some places have disco
lighting even when there isn't a storm. A high resistance neutral
would make the phase voltages bounce about as the load distribution
changed across the 3 phases wouldn't it?

I've suggested that people complain to the DNO about the rate at
which they get through filament light bulbs or the fact that kit
"just dies", anything from DECT phones to Sky Boxes.

--
Cheers
Dave.

In article o.uk,
"Dave Liquorice" writes:
On Sat, 15 Feb 2014 18:54:02 +0000 (UTC), Andrew Gabriel wrote:

The PW182RE4800F02
(http://www.proxim.com/downloads/prod...N_69823_A4.pdf)
claims to be 19W max, and doesn't claim to conform to any PoE
standard (specifically says it doesn't conform to IEEE802.3af).

Looks like it just applies power direct to pairs 2 and 3. If
that's not the case, it doesn't say what protocol it uses to
negotiate.

What kit is on the other end consuming the power?

Varies but Proxim MP.11 5054 which states "20 W max". A 19 W max
supply is sailing a bit close to the wind IMHO... Bit of a power
glitch the unit pulls more power just when the volts is low so up
goes the current a phizt...

You could easily be losing 5W or more in the cable too.
How long are the longest cable runs?

It's geographic as well, one village has virtually no problems,
the
town and a couple of other villages do. Everywhere is fed via
various
11 kV lines from the same 33 kV substation. I wondering if there
is a
fundemental problem in/around the 33 kV substation or 11 kV
switching.

Or a spike on the LV phase due to damaged 3-phase neutral?

Now there's an idea. From what I've heard some places have disco
lighting even when there isn't a storm. A high resistance neutral
would make the phase voltages bounce about as the load distribution
changed across the 3 phases wouldn't it?

Yes. Can also cause quite a spike if one of the other phases
has a short circuit.

I've suggested that people complain to the DNO about the rate at
which they get through filament light bulbs or the fact that kit
"just dies", anything from DECT phones to Sky Boxes.


--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

In article o.uk,
"Dave Liquorice" writes:
Hi,
Does anyone know of a PoE injector that doesn't let the magic smoke
out if the power glitches? Local community broadband lost four more
yesterday that's on top of the 40 odd in the previous six months.
That's a significant amount of money at £20 each...
They have used Fairway Electronic Co. Ltd VE20C-48A and SL Power
Electronics PW182RE4800F02 with negliable difference between 'em.
These are (supposed to be...) IEEE 802.3at (note t not f(*)) devices,
IEC mains in, ethernet and ethernet + (proper) PoE out.
(*) That is PoE+ or PoE Plus which can deliver up to 25 W to the
remote device rather than the 15 W of IEEE 802.3.af.

Have you had them checked by the manufacturer (or anyone else)
to diagnose the fault?

If the wires go outside the building, what lightning protection
do you have on them at the building entry point?

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On Thu, 13 Feb 2014 22:16:04 +0000 (UTC), Andrew Gabriel wrote:

Have you had them checked by the manufacturer (or anyone else)
to diagnose the fault?

The manufacturer is just one of a million "generic" PSU makers in
China, It's not unknown for them to be DOA. I hope to get a look at a
few samples of the dead next week.

If the wires go outside the building, what lightning protection
do you have on them at the building entry point?

None but I'm pretty sure this isn't lightning or static damage as we
tend not to get thunder storms up here. But ice/trees on the lines do
cause auto reclosers to play. The fault currents may well cause
spikes in the distribution.

--
Cheers
Dave.