[time-nuts] UPS for my time rack
brooke at pacific.net
Tue Oct 13 17:02:48 EDT 2015
I really like Power Pole connectors. Unlike cigarette lighter plugs and sockets where the spring causes them to
separate on their own the Power Pole connectors "snap" together.
The Amateur Radio Emergency Services (ARES) used to use car trailer connectors but long ago switched to Power Pole
connectors in a specific configuration that maintains their Hermaphroditic <http://www.prc68.com/I/PowerPole.shtml#Herm>
nature. That's to say unlike conventional electrical extension cords that have a male and female end, in this system
both ends of the cord are identical. The ARES configuration is
"Red on right
A reads right"
The PP15 series plastic shells used for ARES can accept contacts rated at 15, 30 or 45 Amps, so they can handle quite a
bit of power.
The contacts are also self wiping.
I've come up with a 24 Volt configuration that does NOT mate with the 12 Volt ARES standard, but retains the
I don't like the systems that only change the plastic shell color because they mate with the 12 Volt system.
There are a number of companies making DC outlet strips and various other power management devices all based on Power
For example: http://www.powerwerx.com/powerpole-power-distribution/rigrunner-4005.html
Brooke Clarke, N6GCE
Poul-Henning Kamp wrote:
> In message <4FD0F30EBAEF49609DF207E3EE61C15B at pc52>, "Tom Van Baak" writes:
>> I used to rely on one massive UPS (along with natural gas generator)
>> for my entire lab. Eventually I found it more reliable and convenient
>> to have localized power backup. By local I mean backup for a single
>> shelf, or even a single instrument.
> The big gain is avoiding the DC->AC conversions.
> AC->DC conversions are covered under EnergyStar and similar programmes,
> so they're generally 90% efficient or better.
> But DC->AC conversions, for instance in inverters and UPS's are not
> covered, the argument going that they are only run very seldomly,
> and therefore capital cost would be wasted.
> In the professional segment, UPS's which require a forklift,
> efficiencies are good, in some cases very good, because power costs
> money at that scale.
> But anyting you can fit into a rack will typically have horrible
> losses, the smaller the UPS the worse. I've personally measured
> sub 50% efficiency in one case.
> The argument against running stuff on 12 or 24V DC is the short
> circuit currents, and the absense of an affordable standarized
> For the short circuit currents the only cure is fuses and caution,
> and for connectors there seems to be no hope of a standard - ever.
> China forced USB through as the standard for mobile phones, but
> despite several valiant attempts nobody has ever managed to get
> anything above 5V/5W standardized.
> Here's the website of the IEEE WG which came out with a standard
> (IEEE 1823:2015) this May:
> It will cost you $160 to see the full standard, which is a very
> good and strong reason why adoption will be slow, and nobody
> I've talked to expects it to go anywhere ever.
> At the same time USB has come up with 100W power concept
> which is not compatible, since IEEE uses CANbus and different
> I've not heard any rumours that China man nail this one.
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