AC Plug Pack (wall wart) plugs - suggestions please

On Friday, September 4, 2020 at 11:47:23 AM UTC-7, Don Y wrote:
> On 9/4/2020 10:22 AM, Joe Gwinn wrote:
> > On Thu, 3 Sep 2020 20:28:34 -0700, Don Y <blockedofcourse@foo.invalid>
> > wrote:
> >
> >> Midspan injectors and a fair bit of industrial networking kit (e.g., APs)
> >> are powered from 48VDC.  Not likely found in residences -- but not an
> >> assurance for commercial establishments.
> > 
> > Well, 48 Vdc is the traditional Telcom voltage, so there is lost of
> > stuff available for that voltage.
> 
> I'm not sure how much "wall-wart powered" kit like that exists (?)

There's a fair amount of switches that are intended to power small items
(cameras, WiFi hotspots, IOT debris) and those generally use, not a wall tumor,
but a boa-digesting-a-sheep style 48V brick.

Ideally, this is -48V (the case ground is positive)
One lineup:
<https://www.netgear.com/business/products/switches/>

On 9/4/2020 12:05 PM, whit3rd wrote:
> On Friday, September 4, 2020 at 11:47:23 AM UTC-7, Don Y wrote:
>> On 9/4/2020 10:22 AM, Joe Gwinn wrote:
>>> On Thu, 3 Sep 2020 20:28:34 -0700, Don Y <blockedofcourse@foo.invalid>
>>> wrote:
>>>
>>>> Midspan injectors and a fair bit of industrial networking kit (e.g., APs)
>>>> are powered from 48VDC.  Not likely found in residences -- but not an
>>>> assurance for commercial establishments.
>>>
>>> Well, 48 Vdc is the traditional Telcom voltage, so there is lost of
>>> stuff available for that voltage.
>>
>> I'm not sure how much "wall-wart powered" kit like that exists (?)
> 
> There's a fair amount of switches that are intended to power small items
> (cameras, WiFi hotspots, IOT debris) and those generally use, not a wall tumor,
> but a boa-digesting-a-sheep style 48V brick.

Most switches seem designed to power phones -- ~7W PDs.  And, often
not a PD per port (but some subset of that).  Often an external power
supply can augment the power available to the PSE.  But, these are
usually via "nonstandardized" connectors (certainly not a barrel connector)

E.g., a 48 port PSE would need ~700W of PSE capacity just for "nominal" PDs.
(half that if just dealing with phones; half of THAT if only supporting a
subset of phone ports!)

I've not seen an external power supply larger than a single PSE's
capacity, though (all of my APs can be configured for midspan injectors
or *direct* connection of the wall wart to the AP -- a barrel connector
in each case).  IME (YMMV), any supply that would handle multiple PDs
was integrated into the switch and powered from the mains.

My (~2KW) switch's design is powered from 48VDC -- but, as a hack!
This lets me use the battery in my UPS directly to power the switch
(instead of converting to 120VAC and then back to 48VDC) as well as
sourcing power from a 48V solar panel.

Not "listed" kit, though!  :>

> Ideally, this is -48V (the case ground is positive)
> One lineup:
> <https://www.netgear.com/business/products/switches/>

On Friday, 4 September 2020 19:59:55 UTC+1, John Larkin  wrote:
> On Thu, 3 Sep 2020 18:43:48 -0700 (PDT), Tabby <tabbypurr> wrote:
> >On Thursday, 3 September 2020 23:36:40 UTC+1, Phil Hobbs  wrote:
> >> On 2020-09-02 05:44, Tabby wrote:
> >> > On Wednesday, 2 September 2020 03:01:50 UTC+1, david eather  wrote:
> >> > 
> >> >> I have in mind a project that will use AC Plug Packs. For safety and
> >> >> legal reasons I can't change that, but I am troubled by the low voltage
> >> >> power plugs supplied. They are 2.1mm round plugs just like those on
> >> >> almost any DC plug Pack.
> >> >>
> >> >> Time marches on plug packs get mixed in together and "hey this fits" and
> >> >> pzzzt... magic smoke happens to someones piece of kit.
> >> >>
> >> >> are there suggestions for an alternative plug to use. Doesn't need to be
> >> >> polarized (of course), but something hot plug-able would be nice.
> >> >>
> >> >> Any suggestions?
> >> > 
> >> > One simple solution is run the kit at the highest commonish wart voltage, 30 or 32v. And always make your warts output ac so psu polarity doesn't matter. Another is to add overvoltage protection. Another is to have the dc socket insde the appliance case. Another is to put the whole wart inside the appliance with just a mains connector user accessible. etc etc.
> >> 
> >> I gather you're retired. ;)
> >> 
> >> AFAICT the use of AC warts mostly went out with the 56kbaud modem, and 
> >> for good reason.  That approach requires gigundo wet Al filter caps and 
> >> so on in order to be able to handle 50-60 Hz AC.  What a waste.
> >> 
> >> Cheers
> >> 
> >> Phil Hobbs
> >
> >I prefer wartable goods to run on anything - they won't, but getting partway there is a real plus. If you design for ac in it can run off correct PSUs, wrong polarity & old iron lumps. That was really the motivation behind said approach.
> 
> A transformer has the 120/240 problem. We buy universal-input DC-out
> warts with the full international plug set. There are some really
> weird ones.

If you mean old iron lump ones, I think there were occasional ones that autoswitched.


> >Cap failure doesn't matter if it runs on a dc wart, lytics normally go high ESR low C.
> >
> >
> >NT
> 
> Just put one of these first-thing:
> 
> https://www.digikey.com/products/en/power-supplies-board-mount/dc-dc-converters/922?k=srh05

a nice option if budget is generous. Appreciated by some users.


NT

On 5/09/2020 3:22 am, Joe Gwinn wrote:
> On Thu, 3 Sep 2020 20:28:34 -0700, Don Y <blockedofcourse@foo.invalid>
> wrote:
> 
>> On 9/3/2020 5:29 PM, John Larkin wrote:
>>> We like 24 because it's unlikely that anybody has a higher voltage
>>> wart around, to plug in by mistake.
>>>
>>> Of course, my new pulse generator ships with a 48v wart!
>>
>> Midspan injectors and a fair bit of industrial networking kit (e.g., APs)
>> are powered from 48VDC.  Not likely found in residences -- but not an
>> assurance for commercial establishments.
> 
> Well, 48 Vdc is the traditional Telcom voltage, so there is lost of
> stuff available for that voltage.
> 
> In the US (and I suspect everywhere), the legal dividing line between
> low voltage and lines voltage is around 50 Vdc, so this is the highest
> voltage one can use and not have to follow the National Electrical
> Code for power line systems.  In Japan, this starts at 100 Vac, in the
> US it's 120 Vac, and everywhere else it's ~240 Vac.
> 
>
in OZ it was (is?) 32 VAC, 110 VDC

Tabby wrote:
> On Thursday, 3 September 2020 14:39:07 UTC+1, Michael_A_Terrell  wrote:
>> Clive Arthur wrote:
>>>
>>> Use two connectors, one for each pole.
>>
>>
>>     Is that a Polish joke? :)
>
> one shared between 2 poles.


    I knew one Polish EE. He worked for Square D, and he told the worst 
jokes. Mostly about the 'Polish Mafia'. "You do whata I say, or I shoot 
my family!" is not funny. Neither was the one about burning his lips 
trying to blow up a city bus.


-- 
Never piss off an Engineer!

They don't get mad.

They don't get even.

They go for over unity! ;-)

On Fri, 04 Sep 2020 13:22:34 -0400, Joe Gwinn <joegwinn@comcast.net>
wrote:

>On Thu, 3 Sep 2020 20:28:34 -0700, Don Y <blockedofcourse@foo.invalid>
>wrote:
>
>>On 9/3/2020 5:29 PM, John Larkin wrote:
>>> We like 24 because it's unlikely that anybody has a higher voltage
>>> wart around, to plug in by mistake.
>>> 
>>> Of course, my new pulse generator ships with a 48v wart!
>>
>>Midspan injectors and a fair bit of industrial networking kit (e.g., APs)
>>are powered from 48VDC.  Not likely found in residences -- but not an
>>assurance for commercial establishments.
>
>Well, 48 Vdc is the traditional Telcom voltage, so there is lost of
>stuff available for that voltage.
>
>In the US (and I suspect everywhere), the legal dividing line between
>low voltage and lines voltage is around 50 Vdc, so this is the highest
>voltage one can use and not have to follow the National Electrical
>Code for power line systems.  In Japan, this starts at 100 Vac, in the
>US it's 120 Vac, and everywhere else it's ~240 Vac.

In most standards (including IEC) the dividing line between ELV (Extra
Low Voltage) and LV is 50 Vac. For DC, the limits varies more, most
standards use 60 Vdc, some 75 V and some 120 V (+/-60 V). 

The DC limit must include peak ripple voltage. A 60 V battery voltage
should not be used, since the charging voltage would be over 60 V. For
this reason, typically 48 V (nominal) is the highest battery voltage
used.
 

On Saturday, 5 September 2020 07:50:00 UTC+1, upsid...@downunder.com  wrote:
> On Fri, 04 Sep 2020 13:22:34 -0400, Joe Gwinn <joegwinn@comcast.net>
> wrote:
> 
> >On Thu, 3 Sep 2020 20:28:34 -0700, Don Y <blockedofcourse@foo.invalid>
> >wrote:
> >
> >>On 9/3/2020 5:29 PM, John Larkin wrote:
> >>> We like 24 because it's unlikely that anybody has a higher voltage
> >>> wart around, to plug in by mistake.
> >>> 
> >>> Of course, my new pulse generator ships with a 48v wart!
> >>
> >>Midspan injectors and a fair bit of industrial networking kit (e.g., APs)
> >>are powered from 48VDC.  Not likely found in residences -- but not an
> >>assurance for commercial establishments.
> >
> >Well, 48 Vdc is the traditional Telcom voltage, so there is lost of
> >stuff available for that voltage.
> >
> >In the US (and I suspect everywhere), the legal dividing line between
> >low voltage and lines voltage is around 50 Vdc, so this is the highest
> >voltage one can use and not have to follow the National Electrical
> >Code for power line systems.  In Japan, this starts at 100 Vac, in the
> >US it's 120 Vac, and everywhere else it's ~240 Vac.
> 
> In most standards (including IEC) the dividing line between ELV (Extra
> Low Voltage) and LV is 50 Vac. For DC, the limits varies more, most
> standards use 60 Vdc, some 75 V and some 120 V (+/-60 V). 
> 
> The DC limit must include peak ripple voltage. A 60 V battery voltage
> should not be used, since the charging voltage would be over 60 V. For
> this reason, typically 48 V (nominal) is the highest battery voltage
> used.

Some of the Netgear POE+ switches use a dc power supply rated at 54V.

John

On 2020-09-05 02:49, upsidedown@downunder.com wrote:
> On Fri, 04 Sep 2020 13:22:34 -0400, Joe Gwinn <joegwinn@comcast.net>
> wrote:
> 
>> On Thu, 3 Sep 2020 20:28:34 -0700, Don Y <blockedofcourse@foo.invalid>
>> wrote:
>>
>>> On 9/3/2020 5:29 PM, John Larkin wrote:
>>>> We like 24 because it's unlikely that anybody has a higher voltage
>>>> wart around, to plug in by mistake.
>>>>
>>>> Of course, my new pulse generator ships with a 48v wart!
>>>
>>> Midspan injectors and a fair bit of industrial networking kit (e.g., APs)
>>> are powered from 48VDC.  Not likely found in residences -- but not an
>>> assurance for commercial establishments.
>>
>> Well, 48 Vdc is the traditional Telcom voltage, so there is lost of
>> stuff available for that voltage.
>>
>> In the US (and I suspect everywhere), the legal dividing line between
>> low voltage and lines voltage is around 50 Vdc, so this is the highest
>> voltage one can use and not have to follow the National Electrical
>> Code for power line systems.  In Japan, this starts at 100 Vac, in the
>> US it's 120 Vac, and everywhere else it's ~240 Vac.
> 
> In most standards (including IEC) the dividing line between ELV (Extra
> Low Voltage) and LV is 50 Vac. For DC, the limits varies more, most
> standards use 60 Vdc, some 75 V and some 120 V (+/-60 V).
> 
> The DC limit must include peak ripple voltage. A 60 V battery voltage
> should not be used, since the charging voltage would be over 60 V. For
> this reason, typically 48 V (nominal) is the highest battery voltage
> used.
>   
> 

The standards have all changed, so that they focus on the available 
energy.  The SELV exemption has gone away and been replaced by something 
much more complicated.

(I looked into it a little bit a couple of years ago but didn't need to 
become acquainted with most of the details.)

Cheers

Phil Hobbs

-- 
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

On Sun, 6 Sep 2020 14:39:18 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

>On 2020-09-05 02:49, upsidedown@downunder.com wrote:
>> On Fri, 04 Sep 2020 13:22:34 -0400, Joe Gwinn <joegwinn@comcast.net>
>> wrote:
>> 
>>> On Thu, 3 Sep 2020 20:28:34 -0700, Don Y <blockedofcourse@foo.invalid>
>>> wrote:
>>>
>>>> On 9/3/2020 5:29 PM, John Larkin wrote:
>>>>> We like 24 because it's unlikely that anybody has a higher voltage
>>>>> wart around, to plug in by mistake.
>>>>>
>>>>> Of course, my new pulse generator ships with a 48v wart!
>>>>
>>>> Midspan injectors and a fair bit of industrial networking kit (e.g., APs)
>>>> are powered from 48VDC.  Not likely found in residences -- but not an
>>>> assurance for commercial establishments.
>>>
>>> Well, 48 Vdc is the traditional Telcom voltage, so there is lost of
>>> stuff available for that voltage.
>>>
>>> In the US (and I suspect everywhere), the legal dividing line between
>>> low voltage and lines voltage is around 50 Vdc, so this is the highest
>>> voltage one can use and not have to follow the National Electrical
>>> Code for power line systems.  In Japan, this starts at 100 Vac, in the
>>> US it's 120 Vac, and everywhere else it's ~240 Vac.
>> 
>> In most standards (including IEC) the dividing line between ELV (Extra
>> Low Voltage) and LV is 50 Vac. For DC, the limits varies more, most
>> standards use 60 Vdc, some 75 V and some 120 V (+/-60 V).
>> 
>> The DC limit must include peak ripple voltage. A 60 V battery voltage
>> should not be used, since the charging voltage would be over 60 V. For
>> this reason, typically 48 V (nominal) is the highest battery voltage
>> used.
>>   
>> 
>
>The standards have all changed, so that they focus on the available 
>energy.  The SELV exemption has gone away and been replaced by something 
>much more complicated.

It sounds like you are talking about standards for the EX (explosive
atmosphere) devices
https://en.wikipedia.org/wiki/Electrical_equipment_in_hazardous_areas

In these systems it is critical that the voltage, current (and power)
fed into a device within the EX area is kept so low that it can't
ignite the gas/dust in the EX area. Barriers outside the EX area are
used to limit the voltage and current and a single failure in the
barrier should not admit too much voltage/current into the device in
the EX area.

>
>(I looked into it a little bit a couple of years ago but didn't need to 
>become acquainted with most of the details.)
>
>Cheers
>
>Phil Hobbs

On Sunday, 6 September 2020 20:40:00 UTC+1, upsid...@downunder.com  wrote:
> On Sun, 6 Sep 2020 14:39:18 -0400, Phil Hobbs
> <pcdhSpamMeSenseless@electrooptical.net> wrote:
> 
> >On 2020-09-05 02:49, upsidedown@downunder.com wrote:
> >> On Fri, 04 Sep 2020 13:22:34 -0400, Joe Gwinn <joegwinn@comcast.net>
> >> wrote:
> >> 
> >>> On Thu, 3 Sep 2020 20:28:34 -0700, Don Y <blockedofcourse@foo.invalid>
> >>> wrote:
> >>>
> >>>> On 9/3/2020 5:29 PM, John Larkin wrote:
> >>>>> We like 24 because it's unlikely that anybody has a higher voltage
> >>>>> wart around, to plug in by mistake.
> >>>>>
> >>>>> Of course, my new pulse generator ships with a 48v wart!
> >>>>
> >>>> Midspan injectors and a fair bit of industrial networking kit (e.g., APs)
> >>>> are powered from 48VDC.  Not likely found in residences -- but not an
> >>>> assurance for commercial establishments.
> >>>
> >>> Well, 48 Vdc is the traditional Telcom voltage, so there is lost of
> >>> stuff available for that voltage.
> >>>
> >>> In the US (and I suspect everywhere), the legal dividing line between
> >>> low voltage and lines voltage is around 50 Vdc, so this is the highest
> >>> voltage one can use and not have to follow the National Electrical
> >>> Code for power line systems.  In Japan, this starts at 100 Vac, in the
> >>> US it's 120 Vac, and everywhere else it's ~240 Vac.
> >> 
> >> In most standards (including IEC) the dividing line between ELV (Extra
> >> Low Voltage) and LV is 50 Vac. For DC, the limits varies more, most
> >> standards use 60 Vdc, some 75 V and some 120 V (+/-60 V).
> >> 
> >> The DC limit must include peak ripple voltage. A 60 V battery voltage
> >> should not be used, since the charging voltage would be over 60 V. For
> >> this reason, typically 48 V (nominal) is the highest battery voltage
> >> used.
> >>   
> >> 
> >
> >The standards have all changed, so that they focus on the available 
> >energy.  The SELV exemption has gone away and been replaced by something 
> >much more complicated.
> 
> It sounds like you are talking about standards for the EX (explosive
> atmosphere) devices
> https://en.wikipedia.org/wiki/Electrical_equipment_in_hazardous_areas
> 
> In these systems it is critical that the voltage, current (and power)
> fed into a device within the EX area is kept so low that it can't
> ignite the gas/dust in the EX area. Barriers outside the EX area are
> used to limit the voltage and current and a single failure in the
> barrier should not admit too much voltage/current into the device in
> the EX area.
> 
> >
> >(I looked into it a little bit a couple of years ago but didn't need to 
> >become acquainted with most of the details.)
> >
> >Cheers
> >
> >Phil Hobbs

The current safety standard for audio/video, information and
communication technology equipment is IEC 62368.1:1998.
This does categorise energy sources according to how much damage
they can do, whether it be electric shock, ignition and propagation
of fire or mechanical energy such as fan blades.
One of the boundaries for dc is still 60V.
It does seem to be a generally well thought out standard, although
there are a few areas that are ambiguous and subject to interpretation
by the test lab.
This standard becomes mandatory in the EU and UK at the end of 2020 - we
are currently in a transition period where IEC 62368.1 can be used
alongside IEC 60950.1 and IEC 60065.
I think it only becomes mandatory in Australia and New Zealand in
Feb 2022.  No doubt other countries will vary.

John