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The Post-Incandescent Future

Posted August 19, 2015 2:59 PM by Hannes
Pathfinder Tags: CFL graphene incandescent bulb

I've always admired incandescent light bulbs, and find it amazing that an electrified wire filament could hold a near-monopoly on commercial electric lighting for a century or so. Since the mid-1990s, though, many different lighting technologies have sprouted up, all vying to succeed the trusty Edison bulb.

The incandescent bulb's drawbacks are well known. To begin with, their luminous efficacy-the basic measure of how efficiently they produce light, in lumens per watt-in a word, sucks. A 40 W bulb has a luminous efficacy of about 12.6 lm/W for an overall efficiency of 1.8%. If that sub-2% figure doesn't sound terrible enough, it's only a little under 50 times brighter than a candle. Incandescent bulbs convert most of their energy into heat, which is wasteful unless you're using one to heat a terrarium or power an Easy-Bake Oven. This poor performance and new pushes toward energy efficiency have led governments worldwide to order phase-outs or bans on incandescent bulbs.

Swirly CFL bulbs have grown in popularity and dropped in cost, and they're roughly 3-5 times more efficient than traditional incandescents. LED bulbs are about the same efficiency-wise, although research points to a pretty high ceiling as far as possible luminous efficacy.

More recently, lighting researchers have begun experimenting with the celebrated supermaterial graphene. A graphene-coated LED bulb co-developed by the University of Manchester and its spin-off company Graphene Lighting PLC, both in the UK, will likely go commercial later this year. While the university claims the lamps will be "competitively priced" and manufactured using sustainable components, there's been no mention of a more precise retail cost. It's also worth noting that last month Canadian investors Oriana Resources Corp. signed papers to acquire Graphene Lighting PLC. How this will affect lamp production remains to be seen.

In June, researchers from Columbia University and two Korean organizations announced that they'd jointly developed an on-chip light source using a suspended graphene filament. The device requires little power to heat up to the point of emitting visible light, in this case around 2500° C, and despite being only one atom thick, the graphene strip emitted light visible to the naked eye. While the press release hints that the team's more interested in the lamp's potential heating abilities, it could be useful in transparent displays and optical communications. And in an ironic twist apparently not lost on the research team, graphene is derived from carbon-the same filament material used in Edison's original incandescent bulb.

Despite its history of fearmongering, the so-called US "light bulb ban" only applies to the manufacture of 40- and 60-watt incandescents that don't meet certain brightness standards and efficiency ratings, and there are plenty of other options as far as wattage and bulb type. Still, a select few manufacturers have been producing and marketing "rough service" bulbs that legally buck the US ban on general service bulb production. At most retailers these "newcandescent" bulbs carry a steep price tag (over $5 per bulb), so you're probably better off biting the bullet and getting the cheaper CFLs anyway.

As the era of incandescent bulbs winds down, it seems we're only certain of the fact that the dominant lamp of the future is still unknown.

Image credit: Vinovin/CC BY 2.0

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#1

Re: The Post-Incandescent Future

08/19/2015 8:05 PM

The 'less than 2%' figure is often used, but it's not correct. The real figure is almost exactly 6% for a standard incandescent light having a 2500 Kelvin color temperture.

Now granted, 6% isn't great. But the 'less than 2%' figure includes transmission line losses from the generator source to the light bulb, which is a loss that all types of lighting will experience including CFLs and LEDs.

For halogen incandescent light bulbs running at a 3000 Kelvin color temperature the efficacy is around 12%.

What's ignored in such analyses is the simplicity of lighting systems using incandescent light bulbs compared to other lighting systems, the power utilized to make them vs making the much more complex CFLs and LEDs, and the power utilized to dispose of the waste.

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#2

Re: The Post-Incandescent Future

08/19/2015 8:32 PM

I still only want to use incandescent bulbs in my attic. I hardly go up there so why waste an expensive bulb that only gets turned on a couple of times a year. Plus the old bulbs are a lot more tolerant to high temperatures.

Most of the rest of my bulbs are CFL's and some are going over to LED's as the price/light quality improves. I just bought some 40W equiv LED globes for bath fixtures at Sam's Club. $10 for a two pack. They only use 5W each and look just as good if not better than the tungsten version. Went back again today to buy some more and they are sold out.

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#3
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Re: The Post-Incandescent Future

08/19/2015 10:25 PM

Walmart offers a good assortment, you pay extra for the dimmable version...here's a 60 watt equivalent for $2.44 , also the color does vary, 3000k is more bluewhite and 2700k is less of a glare...the watt usage and lumens output varies as well...so it might take some experimentation to find the perfect light to suit your taste for a specific location....

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Re: The Post-Incandescent Future

08/19/2015 10:43 PM

By and large, I have not been satisfied with alternatives to my preferred 3 - way incandescent bulbs. The light output I have seen is NOT good for reading, at least not for what I have experimented with. To be fair, I have not yet tried the new LED bulbs but at the cost of them I don't feel like investing that kind of money only to find they are inferior in terms of useful illumination.

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#5

Re: The Post-Incandescent Future

08/20/2015 8:34 AM

I tend to look at it in a different light(pun intended). In my plant, I have been converting to alternate lighting, in particular, LED, not only for the reduced power consumption but also the reduced "maintenance" costs. The cost of the bulb is only one part of the story, the more expensive cost is sending a person out/up to change the bulb. That cost is usually more than the bulb cost. At home you really have no extra cost except what you spend in gas money to go and get the bulbs.

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#6

Re: The Post-Incandescent Future

08/20/2015 10:08 AM

"so you're probably better off biting the bullet and getting the cheaper CFLs anyway."

Not if you've got original artwork on the walls. 9And if you dabble in art, or have friends/relatives who do, your going to gave originals up there.) Even with all the 'UV blocking' glass they're supposed to make the bulbs from, and the 'UV blocking' glass used on picture frames, CFL's WILL fade original artwork over time. They'll fade ALL artwork, but if it's a lithograph or a piece of computer-printed art, you can always just get a new copy. You cannot get a new original, that's the POINT of it being original artwork.

Check out any Fine Art museum in the world, they'll only be using incandescent lights in the galleries. Possibly LED lighting, since there are no real UV emmissions from blended RGB LED lamps (plus, if you've got seperate dimmers for each channel, you can make the light any color you want), although there will be some UV from 'white' LEDS, which are actually blue-UV leds with a yellow phosphor coating, the human eye combines blue and yellow to make white, although the paintings won't look 'right' under white LED, since it's not REAL (broad-spectrum) white light.

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#7

Re: The Post-Incandescent Future

08/20/2015 12:04 PM

"so you're probably better off biting the bullet and getting the cheaper CFLs anyway."

I'm surprised they still make CFLs! I haven't bought one in at least 5 years. They are unreliable (I have a box of dead ones in the garage), they are very fragile (that box contains the remains of several broken ones), they are hard to dispose of properly (which is why that box is still there), they contain mercury (used to in the case of the broken ones), many of them take a while to reach full brightness (especially when they are cold), they tend to have a yellowish color (probably to imitate the incandescents they are to replace), and they emit a lot of electrical noise.

The only positive I see for CFLs is their energy efficiency, and current LEDs exceed that efficiency.

There are a lot of different kinds of LED replacements, and obviously some are better than others in one aspect or another, but they have none of the disadvantages listed for the CFLs. I did have a few of the early LED lamps fail partially or completely, but I considered that an investment in the development of the technology. Not a single one of the 20 or 30 LED lamps I've purchased over the last 3 or 4 years has failed. That 20 or 30 lamps does does not include the several hundred Christmas lights I've gotten. I've never broken one by dropping it or stepping on it.

LEDs can be discarded along with other e-waste, contain no mercury and only tiny quantities of other toxic substances (as do virtually all electronics), have full brightness instantly at any ordinary temperature, have what I consider much more pleasing color (as long as they have a color temperature of 2700K or higher), and emit much less electrical noise than CFL's.

To check that last item, and verify the efficiency, I recently checked the current waveforms of several different lighting devices. I placed a precision 0.1Ω resistor in series with each device, so you have to multiply the indicated RMS currents by 10 to get the actual current. The measured voltage during the test period was steady at 123VAC 60Hz (to be precise, it varied from 122.7 to 123.0). Here are some typical waveforms:

First, a standard 40W incandescent lamp. Sorry, not a very clear image, but it is the expected sine wave. 0.333A * 123V = 41.0 Watts actual.

Above is the standard CFL "curly lamp", labelled 14W. The waveform is highly non-sinusoidal, and contains considerable oscillator noise. 0.197 A * 123 V = 24 Watts actual power, so not as efficient as they claim.

Above is the standard dual 4' shop fluorescent light with an electronic ballast. They are commonly thought to use 10 Watts per foot, so this would be 80W. It is a much less drastic deviation from sinusoidal than the CFL, and has less high frequency noise, in this case at 43kHz. 0.736 A * 123 V = 90.5 Watts actual.

This is Costco's LED shop light, purchased just a couple of months ago, and labelled 38W. It looks essentially like the dual 4' fluorescent, although it is only 3.8' long. The overall waveform is amazingly close to a sine wave, although it does contain some high frequency noise. If I measured the HF frequency, I didn't write it down. It is considerably brighter than the similar fluorescent, and has a whiter color. I bought one to try, and immediately went down to buy another. 0.387 A * 123 V = 37.7 Watts actual.

Finally, here is a standard LED Lamp, rated13W. Again, fairly close to a sine wave, but this time with an interesting glitch at about 2/3 of peak voltage. 0.096 A *123 V = 11.8 Watts actual.

I'm not happy with these images. One of these days I hope to do it again with a better camera/lighting setup, and if I can find something appropriate, I'd hope to get some measure of light output.

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#8
In reply to #7

Re: The Post-Incandescent Future

08/20/2015 12:32 PM

Still, clear enough to get the information across, Incandescent produces the least electrical noise (it's a passive component, just a resistor)

Second is the LEDS, with mostly sinusoidal patters, and a little low-amp noise from the control circuits.

Third place goes to the ballasted flourescent, which really mangles the sine wive.

And last place goes to the curly bulbs, which throw out enough spikes to build another Transcontenental Railroad, if you'll allow the fanciful metaphor.

What we really need to get LED lighting to take off is for there to be a 'sea change' in the way lighting is wired in the house. Reserve the 110VAC voltage for power outlets and use 24VDC to supply lights and ceiling fans. We can make fan motors that will run on 24VDC, and LED lighting will be simplified by DC power, no more rectification issues, and dimming LEDs becomes much easier, as the dimmer switch would just be a voltage divider to reduce the CD voltage, instead of the complex devices we use now to 'chop off' the AC after so many degrees of the sine wave, which the AC-DC converting LED lights have to compensate for to count as 'dimmable.' From there it even becomes child's play to use the 24VDC to run in-wall USB 'fast chargers' that would power/recharge a cellphone or tablet.

Add to that the fact that anything below 50 Volts is considered Very Low Voltage, and therefore not regulated under the electrical codes, and the lighting becomes so much simpler to wire up, especially in a place like Chicago, where the codes require everything 50V and above (which would mean, the 110/220 service) to be inside metal pipe. You could even run the 24VDC in the same PVC pipe as Cat5E/Cat6 cable, simplifying the work to get a house 'network ready.' (I personally find hard-wiring a network to be more stable, and more secure, than relying on wireless for everything.)

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Re: The Post-Incandescent Future

08/25/2015 2:34 PM

Low voltage lighting has been around for a long time. It is used in travel trailers and motor homes. I like the idea of a dedicated 24VDC lighting circuit for houses. An AC to DC converter would be installed alongside the regular AC panel with a terminal strip to tie in the individual low voltage wiring circuits. It could be retrofitted to existing homes at little cost (no tearing into walls or ceilings). Switched fixtures would be kept the same; only the "hot" side of he power would be terminated and replaced with the + from the converter; easily a DIY job. There is already a huge selection of low voltage lighting fixtures on the market. I suspect any resistance (no pun intended) to low voltage wiring systems would come from electricians and their unions.

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#9
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Re: The Post-Incandescent Future

08/20/2015 12:34 PM

One thing I noticed with CFLs is the effect they have on switches, where the load becomes inductive rather than resistive.

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#11
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Re: The Post-Incandescent Future

08/20/2015 1:06 PM

I hadn't thought about that, but with those high current spikes, It could indeed be a problem for light-duty switches, especially in an industrial/commercial situation where one switch (or relay) controls many similar lamps.

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Re: The Post-Incandescent Future

08/20/2015 1:15 PM

Yeah, you'd think they would have tried to ballance it out with some sort of ballast, like the straight tubes have in their mountings.

Unless whoever approved the design thought adding a ballast was a 'waste of money,' and ignored the potential damage such loads would do to their control switches.

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Re: The Post-Incandescent Future

08/20/2015 1:23 PM

I noticed it when flipping on the outside light. I could see the arc in the gap between the toggle and the faceplate in the dark room. I tried both incandescent and CFLs. the CFLs won the spark test. Although not a scientific experiment, it did give a clue to why I have had to replace the three way lamp switches when using CFL three ways.

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#10
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Re: The Post-Incandescent Future

08/20/2015 12:56 PM

Very nice graphical representation....thanks for sharing

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#14
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Re: The Post-Incandescent Future

08/20/2015 2:44 PM

This is easily the best thing I've seen on the Internet in quite a while. May I share the link to your response?

http://cr4.globalspec.com/comment/1109121/Re-The-Post-Incandescent-Future

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#15
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Re: The Post-Incandescent Future

08/20/2015 2:52 PM

Thank you, and sure!

You've just raised the priority level of doing this again, but better.

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#16
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Re: The Post-Incandescent Future

08/20/2015 4:10 PM

Thanks. I'm trying to wrap my head around the different types of lighting. Growing up an thinking strictly in Watts, a unit of power, has crippled me for proper comparison. I try to understand lumens, candles, candela, Kelvin, but I haven't gotten anything fixed internally, yet, so as to be intuitive. Seeing this little demonstration in Watts makes sense to me.

One thing I'd like to do is take this to the local high school, there's only one, and help them replicate this. I think this would be a great learning lab.

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#17
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Re: The Post-Incandescent Future

08/20/2015 6:11 PM

I too have difficulty with the various units of light intensity and energy.

Please do take it to the school! They probably won't have an oscilloscope with a digital readout like mine, but there is no reason they could not use a digital (or even analog) voltmeter in parallel with the 'scope. I'll make a drawing of the setup and post it shortly...Just make sure the resistor, 'scope, and voltmeter are on the neutral side of the power line. In case they don't have one, very low value resistors are common in the charging circuits of laptop computers. Surely someone in the class knows of somebody that has a dead laptop. I'm almost certain I've seen 0.1 Ω resistors there, but I just looked at three dead laptop logic boards, and I saw 0.05Ω, 0.025Ω, and 0.015Ω, but no 0.1 Ω resistors. Of course any of those values would work, when used with an appropriate scaling factor, as long as the 'scope and voltmeter have sufficient sensitivity.

I used 0.1Ω, because I had one on hand, it barely reduces the supply voltage, and the scaling factor is 10, so I just move the decimal point one place and I'm done. You could also use a 1.0Ω resistor and a scaling factor of 1, with still a very small reduction in supply voltage.

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#18
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Re: The Post-Incandescent Future

08/20/2015 6:25 PM

Good recommendations. I'd have to work this out with the instructor, but it looks like a decent practical lab to me.

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#19
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Re: The Post-Incandescent Future

08/20/2015 7:21 PM

Here's the basic setup:

There are all sorts of things that can be taught using this setup. I've loved the oscilloscope for at least 60 years, because it so graphically shows what is going on! I'm definitely a visually/graphically oriented person. If anyone needs help using this, they can contact me via a personal message here in CR4 (click on my avatar).

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#20
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Re: The Post-Incandescent Future

08/20/2015 7:29 PM

Correction!

I doubt if anyone would notice, but in the text for the Costco shop light, I put down 0.387 Amps, reading if from the blurry 'Scope image. I checked with my spreadsheet of data, and the value should be 0.307 Amps, which when multiplied by 123 Volts does indeed give 37.7 Watts of power.

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#24
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Re: The Post-Incandescent Future

11/01/2015 12:53 PM

Two points :

CFLs are not that unreliable, I fitted 3 "100W equivalent" 240V bulbs in our living room luminaire in 1999 and one is still working, only in the last two years have two failed. They took 500 kWh off the annual electric bill. I guess they were made in Europe not China! Another factor which just occurred to me is that these bulbs are nearly horizontal rather than usual "cap up"- must help the electronics to avoid tube heat. I think that frequent switching knocks the life claims a lot. Another factor may be that 115V is double the current for the electronics c.f. 230V & probably twice the dissipation/heating

I am not sure your power measurements are all accurate - with none-sinusoid currents, one cannot just multiply amps by volts, even if the amps are r.m.s. I use integration of V x I over several cycles on the ".csv" screen dump of my digital oscilloscope.

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#25
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Re: The Post-Incandescent Future

11/01/2015 8:25 PM

Interesting! I don't believe I've ever seen a CFL made anywhere else but China. From my experience with other devices, I would expect them to last longer when made elsewhere. I commonly write the installation date on lamps, but unfortunately I have not kept a record when I replaced them.

There is no doubt that the horizontal position is preferred over base up, and it may well be preferable to base down.

Since fluorescents are inherently high voltage devices, you are probably right on the 230/115 V concept. Now when it comes to LEDs, the 115V will have the advantage.

I can't argue about the power calculations. My 'scope is still working well, but it is around 25 years old. It does have the digital display for any one value, but only one...

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#26
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Re: The Post-Incandescent Future

11/02/2015 6:22 AM

Thanks dkwarner, for putting revealing evidence into the discussion.

On the power measurement, for capacitor input power supplies, like in the CFLs, the current shape is nearly triangular and the current draw is all near peak voltage. Because the voltage near peak is flattened & almost constant, you can estimate the mean volt value during the current draw. You can also estimate a right-angle triangle of current equivalent to the curvy trapezoid on the screen and take the area as 1/2 height x width to get a mean current over half-cycle. Considering it as a DC pulse current at nearly fixed voltage the watts comes out within ~10% of doing an elaborate calculation and a lot closer than rms volts x amps.

I usually do a check this way to make sure I have not made a stupid mistake in the integration or scaling factors.

If you need greater accuracy, you can pencil the scope traces onto translucent paper and split the time into several intervals to measure the V x I better.

The picture is the current & volts to my laptop. Peak volts 333, peak amps 0.88. Watts estimated 26. Mains volts at home always seems a bit clipped flat at the top - I guess it is all the electronics which only conducts near peak volts!

regards,

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#27
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Re: The Post-Incandescent Future

11/02/2015 10:19 AM

As to the power measurement/calculations, the important thing would be to know how the power company's kWh meter reacts to non-sinusoidal currents.

I have a 'smart meter", which was installed a few years back. I have no knowledge of how it handles power measurement. I do know that my electric bills dropped significantly after they installed it, and have stayed lower. I did not pay attention to whether the meter was installed at or near the same time as a change in rate structure...

Nice sharp image! Is it a photograph, or does the 'scope provide that as an output to a computer? The 333V voltage threw me off for a second, 'till I realized you did say Peak... Does the 'scope provide RMS values for comparison?

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#28
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Re: The Post-Incandescent Future

11/02/2015 2:16 PM

You are right that the metering will have an effect. My meter is still a spinning disc electromechanical. A smart meter is threatened sometime. I do not know what "smart" will mean.

The church hall got a smart meter a few months ago - it seems dumb to me because there is solar generation and although we know how much is generated [from a dedicated meter] and how much is bought-in, the actual consumption of the building is now unknown - because there is no export value. So far as I can tell, the previous electronic meter could record export, if only they had programmed it to do so, so I guess this one could.

My oscilloscope is a USB attachment to a computer (Stingray DS1M12 +/- 12 bit 1Ms/s 250 kHz analog bandwidth DC/AC coupled). It does a .bmp file dump of the display, which I convert to .png to reduce the file size or a .csv text file of recorded values. It also has an rms/mean/peak/frequency display window for each channel & a 10 bit output generator sine/square/triangle which can also cycle through a file of user-defined values. There is also data log software which can record for extended periods. It has well repaid me over the 8 years I have had it.

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#29
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Re: The Post-Incandescent Future

11/02/2015 3:58 PM

Very interesting. Right now, I'm recording the voltage and current used by a vacuum furnace (480V 3Ø, up to 450A/phase) We rented a Dent ELITEpro™ XC Logger and current transformers to do it, but I'd love to have our own equipment...

That's very good news that you are still happy with it after 8 years. Now if they only had software for Macs...

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#30
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Re: The Post-Incandescent Future

11/03/2015 6:19 AM

That's most interesting. I have used the Magnelab Inc CTs.

MAGNELAB

600 Weaver Park Road, Longmont, CO 80501

Phone (303) 772-9100 Fax (303) 772-9400

They give a standard 333 mV full scale voltage o/p - no real limit on length of voltage output leads, but my 50 amp nominal one can go up to 200 amp. They come in split core or normal. A great improvement, for the electronic era, on the 5 amp standard CT.

If you have a really challenging problem where CT saturation is a bugbear or very high bandwidth, Rogowski coils are expensive.

http://www.pemuk.com/

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#31
In reply to #30

Re: The Post-Incandescent Future

11/03/2015 10:22 AM

Thanks for the info. I will be Investigating further...

A little over 60 years ago, My mother played the organ at a church in Longmont.

We are using Rogowski CTs that were provided with the logger.

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#32
In reply to #31

Re: The Post-Incandescent Future

11/03/2015 12:45 PM

dkwarner,

I got my USB scope from http://www.easysync-ltd.com/

The USA is listed as www.alliedelec.com. Also, Mouser Electronics are listed as distributer.

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#21

Re: The Post-Incandescent Future

08/21/2015 2:17 PM

I'll give up incandescent bulbs when they pry them from my charred, dead fingers.

I like the trend toward different types of lighting. More choices is good. What I don't like is the damn government then eliminating some of those choices. I like incandescent. I don't like CFLs - for all the previously mentioned reasons. I really like LEDs more and more as their cost comes down.

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#22

Re: The Post-Incandescent Future

08/21/2015 11:59 PM

The meaning of light measurement terms....

The lumens are a measurement of the total light output...to double the light output you multiply the lumens by 4...

...."the range of the light will double and the light will appear twice as bright to the eye.

This is because the perceived light intensity is proportional to the square root of lumen output. So if you double the lumens, the light is only intensified by a factor of square root 2 or 1.41 times as bright. It should also throw 1.41 times further also, as long as you compare the same light with different outputs as the beam angle is very important here. A smaller beam angle will throw farther than a wide beam angle."

http://www.theledlight.com/lumens.html

...converter calculator...

http://www.translatorscafe.com/cafe/EN/units-converter/luminance/3-7/candela%2Ffoot%C2%B2-lumen%2Fmeter%C2%B2%2Fsteradian/

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#33

Re: The Post-Incandescent Future

03/07/2017 8:56 PM

Incandescent lamp luminous efficiency and LED there is a big gap, there is the irradiation surface may be similar, but in the height of the irradiation or there will be a certain deviation

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#34
In reply to #33

Re: The Post-Incandescent Future

03/08/2017 1:37 PM

Welcome to CR4!

It appears that English is not your first language. I think you are saying something more-or-less equivalent to:

The luminous efficiency of LEDs is vastly greater than that of incandescent lamps. Although the area from which the energy radiates may be similar, there is a large difference in the spectrum of light radiated.

Both of these statements are true. If that is not what you were trying to express, then please try to rephrase your statements.

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