What is this???

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egnlsn

Senior Member
Location
Herriman, UT
Occupation
A/V/Security Technician
Are all of the power supplies basically in parallel

60 V AC and it would be difficult to keep them all in phase so, no.

-Hal
Not just that, but after so many active devices and so many miles of coax, the voltage drops too much to be able to power devices.
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
If paralleling all supplies were done voltage drop would be taken care of the same as it is now with isolation- by installing many supplies. So it really wouldn't make much difference.

You could reason paralleling would be desirable for redundancy however losing one would cause a domino effect, overloading other supplies so they go off line which in turn overloads other supplies and so on down the line. That's why each section is separately powered so any problem won't effect the others, and it's much easier to locate.

-Hal
 
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Jacob S

Senior Member
Great info. I have noticed that several in my area actually have a natural gas connection too. These are about the size of the one pictured, but mounted on a small concrete pad. Is the gas connection for a small generator inside?
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
How about throwing bridge rectifiers on each of the LV utilities and stealing some power to charge batteries? :cool:
 

Rampage_Rick

Senior Member
They actually just installed a couple of those round these parts to power LED highway condition signs out in the boonies. (On the highways that get the most extreme weather) I'm guessing they're more dependable than the lead-acid backups they were using before, and if plumbed into natural gas they should have a substantial runtime.

Here's the location of one.

Funnily enough, the fuel pump on my truck died on Christmas day not 30 seconds from that spot... here
I had a few hours' wait for a tow, so I was giving that setup a real lookey-loo.

($250 for the tow, $400 for fuel pump, $350 labour - Ho Ho Ho, merry Christmas to me... :D)
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
I'm guessing they're more dependable than the lead-acid backups they were using before

If you notice those generators output DC. The batteries are still there, the generator just keeps them charged. In the case of cable when utility power fails but I suppose with those signs there would be no utility power so the generator runs every so often to charge the batteries. I have seen solar used for this too and I could see a generator also for when the sun doesn't shine.

-Hal
 

Rampage_Rick

Senior Member
Yeah, I can see you waving. :roll: :)D)
Yeah... with my middle finger... I had a 2 hour wait, and it was cold enough that my 6-pack of pepsi froze. Also, try to find a shop open between Christmas and New Year's. Got my truck back 20 minutes before the shop closed for New Year's Eve.

Just had a thought as to another reason why they might have gas-powered backup in that location... The interchange to the south-west has had some of the most occurrences of copper theft in the province. Around the same time as the gennie went in on the highway sign they installed some radio gear on the lamp standards. My guess is that they can remotely tell if the lights are working.

Those signs all have lead acid battery backups. The controller cabinets are similar to the large ones at intersections. The lower half of the cabinets are full of those cells that look like oversize lantern batteries. In the upper half they have a ~1000W charger/inverter similar to what you'd have in an RV, plus the sign controller and dial-up modem. Originally though, these installations had retro-reflective flip-disk signs, which would hold their message in the event of a power failure. With the new LED ones, no power = no message, thus the likely reason for gas-powered backup on the most treacherous routes.
 
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