Question for Jim Banner and Others

[Yampa Bob]

I have no idea how they are made, but I'm searching. 

I found a FAQ on one site.
http://www.platinumlightinginc.com/Rope/RopeFAQ/ropefaq.html

If I read it right, each 6" section is 12 volts, or six 2 volt bulbs wired in series, with sections wired in parallel. If one bulb burns out, the section is out.

FAQ for LED rope lights.
http://www.platinumlightinginc.com/html/ledfaq.html

The following page describes the typical series/parallel wiring construction.
http://www.freepatentsonline.com/6572243.html

[Chris350]

I use rope a lot in cabinet accent lighting.  It's a sealed string, about 3/8" in diameter, and reasonably flexible.  All the lamps and wires are molded into the rope. No changing lamps.  This link that Bob supplied hits nearly everything you wan to know about the stuff.  When we run sections that need to have dark portions we just spray em black...  Also the strings are marked  to be cut at specific intervals.  It's important to cut at the marked locations, I don't remember exactly why. 

[Jim Banner]

After beating my brain trying to remember who manufactures the rope lights I buy from Walmart, I finally gave up, drove over to the shopping center and bought another set.  They are made by Globe Electric and come in 12 foot lengths which is 144 lights.  The four series strings each contain 36 bulbs which would make them 3.333 volt bulbs, rated 50 milliamps and 25,000 hours.  I rerate them at 3.6 volts, 10,000 hours to make them more comparable with the 10,000 hour long life GOW bulbs that Circuitron sells.  The rope is 1/2" in diameter (not 3/4 as I indicated earlier.)  The 12' rope cost 14 Canadian dollars plus tax.  Not quite as good as Bob's 30' for $8, but I didn't have to pay shipping and a $25 brokerage fee (they won't ship USPS) and tax on all of the above.
Globe Electric has a not too informative web page on their rope lights at:
http://www.globe-electric.com/html/products/cal/flexible/products-cal-flexible-FAQs.htm

I have uploaded some photos of these rope lights and the bulbs taken out of them on one of my websites.  Clicking on the link below will take you to an index of these photos.

http://members.Shaw.ca/the.trainman/rope-lights/ 

The photos include:
- a photo of the rope lights in their package,
- a comparison of two bulbs from the rope lights with 4 different brands of GOW bulbs, and two 3 mm LEDs,
- a photo of the whole rope lit up,
- a close up of the lit up rope,
- two photos showing coal oil lamps made with these bulbs.  These are for lighting up the freight shed and the waiting room of the 1880s station I am building in 0-scale.  For comparison, they are shown with two passengers from the waiting room.  The hanging lantern is powered through the two fine wires that are twisted together to make the rope.  The other two are powered from below.  They were three of the four lights of a four light string running off a nominal 12 volt transformer.

Jim

p.s. to Chris350 - the bulbs are not all in parallel.  They are series strings of 6 to 36 bulbs, with the strings in parallel across a pair of traveler wires.  If you cut between the marks, you will open up one of these series strings and all the remaining bulbs that were in that string will no longer light.  It works the same with LEDs - they too are in strings but with different numbers of LEDs per string.

JB

[Yampa Bob]

Jim
Did you derive the 50 milliamps from measurement, or from the total wattage of the 12 foot package?

Some listings I found had wattage high as 5.5 watts per foot.

We have a local Walmart, I hope they have the lights in stock. The only one listed on their website is 39 feet for $16, but no details.
http://www.walmart.com/catalog/product.do?product_id=8486792#ProductDetail

[Jim Banner]

Bob, the package indicated .22 amps maximum (which would be 2.2 watts per foot.)  Actual measurement on that one rope with 121 volts rms applied was .190 amps which is an average of 47.5 milliamps per string or per bulb.  On an earlier string, individual bulbs drew 51 milliamps at 3.33 volts dc applied.  I did some further testing of number of bulbs versus current with the string connected to a nominal 12 volt transformer which actually produced 14.0 volts during the test.  The results were: 3 bulbs in series = 60 mA; 4 bulbs in series = 52 mA; 5 bulbs in series = 46 mA.  If you calculate the resistance of the strings, you will find it increases only 130% going from 3 to 5 bulbs while the number of bulbs increases 167%, meaning the bulbs tend toward being constant current devices, that is, the current through rises at a slower rate than the voltage across them.  (Compare this to LEDs where the current rises at a faster rate than the voltage, making them constant current devices.)

Jim

[Chris350]

p.s. to Chris350 - the bulbs are not all in parallel.  They are series strings of 6 to 36 bulbs, with the strings in parallel across a pair of traveler wires.  If you cut between the marks, you will open up one of these series strings and all the remaining bulbs that were in that string will no longer light.  It works the same with LEDs - they too are in strings but with different numbers of LEDs per string.

JB

That's right.  I just cut em where they were marked, and filed away the reason why.

[Yampa Bob]

Thanks Jim,

Compare to the specs on some commercial lights I found at a Denver site:

http://www.noveltylights.com/Spec_catalogs/120V%20ROPE%20LIGHT%20Spec%20Sheet%20and%20Instructions.pdf

The Globe brand you have is not available locally and they can't order them.