Fluorescents

Ya know, would it be possible to replace all those awful CFLs with one big, reliable ballast supply and a suitable infrastructure to run it?

I'm thinking... constant current HF supply in the basement/attic. Coax runs to all the lamps in the house, maybe a few kV worth, in series. Multiple circuits could be provided from the device so the voltage is realistic. Lights are hooked in series, and if the OC voltage is high enough, they won't even need starters or filaments, they can be cold cathode. Well, that makes things easier.

Justification for new wiring, power supply, lamps, etc. is "new technology", for gutted/new manufacture housing. Put it in once and forget about it, just like any other wiring. Lots of types of wiring have been developed (beyond regular romex, there's telephone, CATV, ethernet, etc.), so it's not like it's a big deal wiring it up. Maybe existing fluo fixtures could be rewired for the system.

Cost: yeah, it's pricey. So is building a frickin house. Buy it once and forget about it. Buy ten cheapass tubes for the rest of your life and you couldn't care less.

EMI/RFI: not a problem. Most fixtures are metal, so run shielded twisted pair. Net field is zero. RF likes to get out anyway, so run it at a reasonable switcher frequency, like 50kHz, and make it resonant, so the output is a filtered sine wave.

Switches might be the hardest, just because you somehow have to convince electricians that *shorting out* the fixture is, in fact, the correct way to turn it off.

Tim

--
Deep Friar: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms
Reply to
Tim Williams
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How are you going to defend liability lawsuit? Plantiff: "I have no idea this was high voltage".

Reply to
linnix

Some old street lighting used to be series wired. There were some sort of overvoltage sensors that shorted a filament if it burned out. And we know how reliable series-string Christmas lights are.

A little better would be one 60-Hz to HF converter, still around 120 VAC. Then each CF fixture would just need one high-leakage-inductance ferrite step-up transformer.

John

Reply to
John Larkin

This is not a new idea.

The 1880's Thomson-Houston street light system was using 25-30 arc lamps in series, driven by a nominally 1500 DC generator. The generator limited the current to 6 A in the loop. Electromagnets in the lamps controlled the distance of the carbon electrodes to perform auto start and current regulation.

Some private shops even had one of the lamps in the shop and when the shop was closed in the evening, the indoor lamp was simply shorted, allowing for a slightly higher voltage for the rest of the street lamps.

Reply to
Paul Keinanen

On a sunny day (Sat, 18 Sep 2010 20:23:30 -0500) it happened "Tim Williams" wrote in :

Makes it difficult at night to replace one... If one goes, like Christmass lights, all go.

Reply to
Jan Panteltje

Microelectronics is so cheap that it's probably more practical to have it in each lamp, as is done now. Maybe the circuit/chips can be improved to have only one part, though. What I think might be economical in the long term would be to have low-voltage AC (or DC) distribution throughout all buildings, to eliminate all the little transformers/power supplies that come with so many new electronic devices. Instead of add-on power strips and clusters of bulky wall-warts, the wall fixture could have the usual

120V AC connectors, plus a panel of low voltage power connectors, say ten or twenty per fixture with 1/2" spacing. It would require some standardization of power connectors on all new devices.
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John
Reply to
John O'Flaherty

Then people will expect to be able to run a PC off of the 5V/12V rails, so you'll end up running 10mm busbars around the house. Even excluding PCs, if 5V/12V DC became standard, you can bet that every consumer electronic device would make the PSU an optional (i.e. chargeable) extra, so you'd still need rails capable of powering every electronic gadget in the house.

Reply to
Nobody

Even so, 24 or 48V rails wouldn't be too bad, and that would be good enough not to require isolation or fancy power supplies. A buck converter will suffice, or synchronous forward for low voltages, or just multiple stages.

It could even influence design. Instead of laptop chargers, they'd just have cords, and the laptops themselves would run on 24 or 48 or whatever, directly.

Tim

--
Deep Friar: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms
Reply to
Tim Williams

In addition to the thick busbars required when using low DC voltages, the device power supplies are most likely not isolated, so the ground signal would be common among many devices, causing all kind of ground potential problems if devices connected to two different outlets are connected together with a signal cable.

If each device is required to have an isolated power supply, then much higher DC voltages could be used, eliminating the need for rectification, PFC and storage capacitor in each device.

Existing CAT5 cables could be used to deliver moderate power using the Power over Ethernet concept (44 V).

A few years ago, there was a lot of talks about using 42 V (3 x "12 V" batteries) in cars, but I have not heard much about it recently. If this becomes popular in the car industry, this might also be an option for in house DC distribution.

24 Vdc is widely used in control systems and heavy trucks and would be a candidate for DC power distribution voltage.

Much small devices are already charged (5 V) through the USB connector, so integrating a powered USB hub into each mains outlet might simplify things. Of course, the 5 Vdc power would have to be generated locally from the normal AC distribution at each outlet.

Reply to
Paul Keinanen

Ah, but we have that already, from all sorts of erroneously grounded equipment. AV equipment is the worst, being the most sensitive to ground loop problems.

DC would be better, because you don't get that awful HUMMM everywhere. Just an offset. And most such circuits are AC coupled, so you don't see the offset, whereas you would get 60Hz.

The next issue that pops up, is your power supply clean enough that it's not whining or hissing or clicking or chattering, especially from other devices on the line? That can be worse, since you can't just notch out

60Hz anymore.

There becomes a large incentive to build cheap, crappy supplies. Who needs caps when the supply is already filtered? Who needs CM chokes when it's only two wires, already grounded?

But there's nothing inherently wrong with such a system. Build quality is for the market to decide, just like it is for everything else today. Consumer electronics is inevitably varying shades of crap, and you get what you pay for. After a few years, competing supplies and appliances figure out their own balance of cleanliness. Who needs standards at all?...

Joy of joys, someone bumps your power cord, it comes loose for a microsecond and the whole thing turns off! What brownout time do supplies manage today, something like 10-20ms?

Meh, at least the cord certainly won't be ancient NEMA-1. Easy enough to specify one with actually reasonable connections.

That would be handy for on-the-go appliances -- plug it in at home, plug it in on the road. Who needs two cords?

Tim

--
Deep Friar: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms
Reply to
Tim Williams

The PC won't be a problem, because it won't be equipped with that kind of connector, and would be beyond the rating of the outlet. The same applies to all the other kinds of device - only those many devices that need little power but still have to be plugged in (those currently running on a wall wart) would be candidates.

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John
Reply to
John O'Flaherty

Just shunt the bum one, swap it out, and remove the shunt. I think some series-string Xmas lights have an automatic thing that shorts the bulb when the filament blows, so the rest don't go out.

Or come up with LEDs that are bright enough to provide actual illumination. :-)

Cheers! Rich

Reply to
Rich Grise

And tons and tons of copper wire. =:-O

Cheers! Rich

Reply to
Rich Grise

Thinking it over some more, I see a better way. If the standardization of small device power supply voltages and connectors could be achieved, all those at a local outlet could be powered by a single transformer/connector panel that would plug into the existing mains. A lot of connector space and transformers would be replaced by a single inexpensive device. It won't happen.

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John
Reply to
John O'Flaherty

Have you seen induction lighting?

Reply to
JosephKK

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