Michael
I know that you have had a long and very varied career in electronics. Have you ever had any experience with cable-suspended traffic lights in Florida or elsewhere in the USA ? Or anyone else on here even ? The question I have is not particularly repair related - more one of general interest really, so I'm happy for any responses to be direct off-group if it is felt more appropriate by anyone.
Arfa
Tell us all, we can skip past it if we don't like it. This is an eclectic group.
H. R.(Bob) Hofmann
OK then. Michael has already come back to me off-group with some useful insights, but any others are of course appreciated. On one of my recent visits to Florida, someone else in the car asked me the reasons for the large cable loops either side of traffic lights which are suspended across junctions on catenary wires rather than gantry or 'fishing pole' mounts.
I guessed perhaps drip loops, sophisticated strain relief, or maybe to allow for cable breakage rewires, but I had to admit that I did not really know, and that I would try to find out when I got back. So, does anyone know for sure, or is it just that it's the way it's always been done, and the real reasons are now just lost in signal repairman tradition ?
Arfa
I can't offer any real answers other than I've seen them done like that here in Florida all my life. All I can say during and after hurricanes I have seen traffic lights hanging from their power wires rather than the steel cable that they are supposed to be suspended from, though I doubt this is the reason for coiling the power wires up.
- Mike
Do you have a picture showing exactly what you're referring to? My uncle installs and maintains these things for a living so I can get a sure answer from him assuming they're the same way in the opposite corner of the country.
I do know that we've been phasing out our spanwire installations over the years in favor of rigid mast arms.
Hi James. I have had a quick look in Google images, but typically, there is no picture that shows what I am referring to. However, I have been assured by Michael T that they are installed the same all over the states, and Michael K says above that they are the same all over Florida at least. I have for sure seen them in Fl, Colorado, Ca and Nevada. I am referring to the large ( a good foot or so I am guessing ?? ) loop that is made in the supply cable on either side of each traffic light set, and which appears to be fixed ( taped ? ty-wrapped ? wire-wrapped ? ) to the catenary suspension wire. Always very neatly done from what I can see. We don't have lights suspended over intersections in this way here in the UK, so I have no idea from personal experience, of the exact reason for them.
Arfa
I will try to get some usable pictures the next time I'm out. I want one of a failing red LED light near here, anyway.
-- Service to my country? Been there, Done that, and I've got my DD214 to prove it. Member of DAV #85. Michael A. Terrell Central Florida
I think this is what you're referring to, maybe...
I've seen them coiled here in TX too. Steve
Yep - that's the loop ok. But curiouser and curiouser as they say ... Those lights only have the loop on one side, and it's the opposite side of each one so that the cable run between the two lights is virtually direct. I wonder what the significance of that is ? I'm really looking forward to James getting a definitive answer from his uncle on this one.
Arfa
I live in Flordia and have noticed same. I am guessing two possibilities that would warrant a long service loop:
1.) When preparing for hurricanes, the cities will sometimes take down some of the redundant lighting, apparently to relieve the wind loading on the structures.2.) Sometimes the lights have to be moved to acomodate the transportati>
This is just my opinion on the looping of the power line on traffic signals... Those loops remind me of my years in the commercial FM radio service business in the Florida panhandle. In the transmitter shack of many of our customers, the antenna feedline would have a loop formed in similar fashion, though those loops were much larger. It was for lightning protection. Theory was that the loop formed an inductance that was effective against lightning strikes on and near the antenna tower. The inductance presented an impedance to the lightning pulse, and prevented it from getting into the transmitter. Seemed to work... here in Florida, the lightning capital of the world, we had very few stations that experienced significant damage due to lightning. I remember one base station just across the state line into Georgia, lightning hit a 200' antenna. The antenna was obliterated, the transmission line was melted down to the bottom of the tower, but the base station only had a blown power supply fuse. I attributed the lack of damage to the base station to the loop in the transmission line. Of course, with lightning, you can never really be sure.
So, my opinion of the loops in the power lines near the traffic signals is for lightning protection. Don't know if that's the real reason for them, but it's surely plausible, especially in high lightning areas.
-- Dave M MasonDG44 at comcast dot net (Just substitute the appropriate characters in the address) Life is like a roll of toilet paper; the closer to the end, the faster it goes.
That's two more good theories from EMI GUY and Dave. Didn't realise what I was starting here, but I'm finding it really interesting, and especially so that even people who live full time in the states, don't know. It's one of those intriguing little mysteries that you can go your whole life without spotting until someone points it out.
Tell you what else that I've found interesting, and that's the number of people who have responded to this thread, who are very regular posters on here, and who it turns out, live in the state of Florida ! I wonder why that is ? I love the thunderstorms in Florida from a 'spectacular thing to watch' point of view, but I don't suppose they are too good for you guys having to deal with the electronic damage that they must cause. There was a mother of a one when I was there last week. At its height, there must have been a lightning stroke every two or three seconds. Very impressive to see. We never get them quite as violent as that here in the UK, but the ones we do get can last several hours, whereas most of the ones I've seen in Florida over the years, tend to be over and done with quite quickly.
Arfa
We had over 7000 lightning strikes in Central Florida on Sunday.
At the last place I lived, i had a battery powered digital thermometer explode from a close strike, in the marsh behind my shop. It also took out all three video amplifiers on my SVGA monitor, even though it wasn't connected at the time, and had the video cable wrapped around the tilt stand.
One bolt hit the TV antenna and damaged about $5000 worth of electronics and building damage. The only things that survived were plugged directly into MOV surge protectors on each item. Anything that was plugged in without one was damaged, even though the power was out. I was in a 16' * 20' wood building with solid steel doors, and no windows with no power. One bolt hit so close that it lit the entire inside of the shop, and it felt like the building was coming off its foundation. That storm burnt the underground power lines to our storage building, the line card in the pedestal for our phone line, and took out a mile of underground copper telephone wire, to the pedestal, and damaged that pair to the Central Office.
-- Service to my country? Been there, Done that, and I've got my DD214 to prove it. Member of DAV #85. Michael A. Terrell Central Florida
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