50/60Hz Frequency

Convention.

Slightly smaller wires.

Mostly, because that's the way it's always been and the cost to change would be astronomical.

60 Hz practical for what?

Why not 16.7 Hz?

http://en.wikipedia.org/wiki/15_kV_AC_railway_electrification

It also is makes more sense considering our commitment to the standard divisions of time units as well as degree divisions on a circle.

Until we convert to base 10 format time and circle divisions, 60 hz will probably remain strong.

I sense an opportunity to go off on a rant about how Del & friends gave us a stupid measurement system based upon a king's body parts and kept the good metric system to themselves.

Rant away! :-!

I would jump on an opportunity like that in a pico-day if they had fully converted over to base ten units, but upholding their moral code of being good sports they handicapped themselves by going through all the trouble and expense for an incomplete conversion.

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Anyway I wouldn't want to be too harsh. Little by little, a nano-circle here, a micro-circle there, and eventually thing have come full circle, and I wouldn't want to be on the receiving end of outrage over having convinced the world of the benefits of base ten time, and then not actually using it myself.

Looks like my milliday is up, but stop by tomorrow or the next day.
I'll be around here for the next two centiyears.

It is not possible in Indian countries because the supply there is 50Hz.

Long knives bring bad medicine...

I gave you a GA because you put a great deal of interesting historical information in one paragraph and at the same time showing insight into Edison's personality. Thank you.

If you touch two 50 hertz wires or two 60 hertz wires, ther both "HURT" the same.

....of the same voltage!!!

Which they are not usually....looking domestically at the statement....or even comparing one at 10 volts and the other at 440.....for example!!

You forgot to mention that....

Blame the colonies for 60Hz. The empire for 50Hz.

I lived for a while in a god forsaken town, Mansfield. The history of the electrical supplies around the area is fascinating.
The mines in the area used various frequencies 12½Hz, 13⅓Hz, 25Hz, 36⅔Hz and 50Hz.
Some of the pit villages could be supplied from two different pits, one side of a street on a different frequency to the other.

I service a Paper Mill on the west coast that has both 50HZ and 60HZ in the same facility, complete with a massive rotating frequency converter.

Historically 100 years ago they had a green field installation - not even a town, so they built their own hydro station on 50HZ. About 50 years later the commercial provincial power came their way and it was 60HZ. So they installed the frequency converter so they could sell power to the province. The new paper machines automatically followed the North American standard of 60HZ, but they still run one paper machine on the original 50HZ.

A decade ago they sold the Hydro station for quick cash and an agreement for a decade of 50HZ power at a preferential rate. That has ended and now the hydro station is shutting down the 50HZ generator, so there is now a scamble to figure out how to either keep the 50HZ "pocket", convert to 60HZ, or shut the machine down.

( ---it is a news machine --- the writing is on the wall.)

Only in Wales.

joganand,

I'd like to know the name of your present employer, and the name of the company with which you have the "technical" interview.

Please share with us that information, so that we can endorse you.
Thank you.

Our OP has 16 posts... all of them threads. Hasn't replied to any previous requests.

Odd...

(Figgered it out... thanks lyn! )

OP says:

"After my graduation(Electrical&Electronics engg)" Really?????

mechanical valves

Not really odd, just typical. Sadly.

Why 60 hz?

Impedance of free space: ≈377 ohms

2 * π * 60 hz ≈ 377 radians/sec

( I had a friend in college who wanted to know why those numbers were the same!)

Yes this is true, but how does that translate to efficiency...?

I was taught that in America they use the clock thus 60 HZ as in one minute and Europe using the metric system assumed that 50 HZ was good. No one ever changed and is that good or bad.. We keep on operating no matter the HZ designed into the apparatus.

So, the minute is a different duration in Europe? 50 seconds?

360 is divisible by 60. Is that where you were going?

Hi Lyn: I am not going any where just passing on the information I was given concerning the variance in the two systems. Fairy tail or not that was what was taught and I agree it matters no.

Not correct.

Our "pole-pig"transformers could be a lot smaller and lighter if the frequency was higher,say 400 hz,like at airports.

Motors could also be smaller,and distribution centers transformers also.

Too bad the frequency was decided before we knew quite as much.

History, history, history......

We all forget that such things were set in stone when the technology to turn the alternators (and build the motors!) were still in their (relative) infancy.....

Some early generators were driven by reciprocating steam engines with their high power/torque, big belts instead of gearboxes, but relatively low speeds, till turbines really caught on, then it was too late!!!

There is an interesting Wiki article here:-

http://en.wikipedia.org/wiki/Power_station

Where you can read this sentence:-

The advent of the steam turbine in central station service, around 1906, allowed great expansion of generating capacity. Generators were no longer limited by the power transmission of belts or the relatively slow speed of reciprocating engines, and could grow to enormous sizes.

Here is a good overview of the 50/60Hz reasons etc:-

http://en.wikipedia.org/wiki/Utility_frequency

Where you can read:-

Commutator-type motors do not operate well on high-frequency AC, because the rapid changes of current are opposed by the inductance of the motor field. Though commutator-type universal motors are common in AC household appliances and power tools, they are small motors, less than 1 kW. The induction motor was found to work well on frequencies around 50 to 60 Hz, but with the materials available in the 1890s would not work well at a frequency of, say, 133 Hz. There is a fixed relationship between the number of magnetic poles in the induction motor field, the frequency of the alternating current, and the rotation speed; so, a given standard speed limits the choice of frequency (and the reverse). Once AC electric motors became common, it was important to standardize frequency for compatibility with the customer's equipment.

I trust this helps further.....

It is because we were British Colony. They had selected 50 Hz power supply so they installed 50 Hz generators etc. They had right hand drive vehicles so we were sold such vehicles.So everything British.

Hard to make the connection, though I am sure it is common thought in India. Canada is just as much a colony and it is all 60 hz.

Almost - there are still a few small pockets of 50HZ, like 1/3 of the paper mill in Powell River. There are a few other small pockets, but I forget just where. I thought there were a couple in Quebec and the East coast, but they may be gone now. Typically old paper mills with their own power generation from 100+ years ago. I still see RFQ's with 50/60 Hz requirements here in Canada.

It is possible for you to set up your own generator at 60Hz for your own industry, but don't try connecting it to the 50Hz grid!

It depends on who you ask. Some say that early generators were easy to stabilize at 1800 RPM rather than 1500 RPM. Others say that George Westinghouse picked the higher number when his brother Herman suggested 133 Hz. Still others point out that Tesla was nutty as a fruitcake and loved multiples of 12. Various places in the US had other frequencies - Long Island may still have 25 Hz for all I know - but it got too complicated to use different ones.

"Still others point out that Tesla was nutty as a fruitcake.."

Of course, Tesla was the last of the great Mad Scientists! He didn't just sip from the Madness Well, he tied the rope to his ankles and dove in head first. How else could he have come up with all these wonderful, bizarre, seemingly impossible concepts?

He loved the ideas of rotating fields and spinning fluids, one of his inventions was a frictionless clutch, there the two plates never touched, but interacted through the lubricating medium between and around them.

He also nearly leveled two square blocks in New York once, when an experiment in harmonics proved to me more energetic than he anticipated. The device would not turn off, he had to smash it apart with a hammer.

Yes he was a loonie, but we should all hope to be so loony when we're seeking inspiration for the Next Great Invention.

True, true, he was a brilliant inventor.

I worked once with an engineer who was a world class expert in track circuits. He held dozens of patents, authored many papers, and traveled all over the world doing work. During his lunch hour each day, he worked on a dictionary translating English into some UFO language whose name I forget.

Nutty doesn't negate brilliant. Along those lines, Steinmetz was no poster child for normal behavior either.

"Nutty doesn't negate brilliant"

To further clarify that point, 'The line between Genius and Madness is imperceptibly thin.'

Except in my case. I'm more than a little addlepated, and at least a country mile from being smart. My sister used to call me idiot savant, but I didn't know savant was her nickname for me.

By the way, I worked with one of Tesla's relatives (3rd cousin, twice removed or something) and she said the family all thought he was nuts too, particularly after he let George Westinghouse buy all his patents for next to nothing.

Maybe she meant Idiots Avant (cutting edge idiots, highly developed or advanced), from latin "abante".

I have no clarification of this but was told several times by several folks that 60 Hz is far more dangerous to humans than 50 Hz. I was told that it is more likly fatal to touch 110 120 at 60 HZ than the common 220 V 50 Hz in Europe due to the 60 Hz is the same speed as nerves from the brain to the heart. But where I see a problem with that statment is the natural pacemaker is located near the top close to the middle of the heart. The brain only controls speed of the heart using chemisty such as releasing hormons from the pituatary that in turn cause the Adreanal glands to release adrenalin.

Anyone know if this is BS. I was told that is WHY 50 was chosen over 60 Hz in most of the world.

Anyone know about this. I was also told that the US was thinking ( I beleave this started in CA (Nuts of the world as well as a lot of smart folks mixed in) that there was a posible bill to start converting as much as possible to 100 Hz. Supposadly it would save energy loss???? and save lives???

Anyone know about that??

I do not see it on a search of the net.

Jimy

"...Anyone know if this is BS..."

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I'm going to go out on a limb without any hedging here and call this BS.

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Chance for stopping the heart is related to the total energy expended in key areas, so watts times seconds exposed. I guess depending on the length of the associated sympathetic and parasympathetic nerves as well as self capacitance and inductance, there might be cases/individuals where either 50 hz or 60 hz might represent slightly more threat.

However, the difference in voltage is certain to outweigh any small difference that might be due to such a small difference in frequency. 220 v 50 hz is going to be far more dangerous than 110 v 60 hz if all other conditions are the same.

Dear Joganand,

I will not jump in to discuss the advantages of running at 50 Hz or 60 Hz. All I can tell you is, my country, Venezuela, was 50Hz all over until 1968. The decision was taken at Presidential level to change to 60 Hz, and a three-year period (1968-1971) was assigned for all of the country to run at 60 Hz. I got my EE degree in 1969, so discussion was very active, and I participated in forums, committees and so on. The frequency-changing procedure was traumatic, lots of fridges burnt out, belt coupled MG sets all around, plants losing productions, all sorts of motor were rewound (imagine, for one, how to rewind a 50Hz Schrage motor to run on 60 Hz); lots of disappointments, mishaps, grudges and the like.

A privately owned, major paper mill decided to stay at 50Hz and ordered a new big gas turbine to keep generating 50 Hz for themselves.

Small cities with diesel powerplants kept running at 50Hz until substations were built and tied to the 60Hz grid.

The outcome, as seen almost 50 years later? NOTHING. No further progress, no real improvement in any area. The paper mill ran at 50 Hz for some 10 more years, then entered a 50Hz-60Hz period with separate areas in each frequency, with an awful lot of associated trouble, and finally they shut down the 50Hz turbine because it was too expensive to modify to run at 60 Hz. They bought four packaged ones at 60 Hz, instead, and increased their tie to the 60 Hz grid. I know, I was there.

For the rest of the country, no changes at all.

For me, the only difference was that 1 cycle took 20ms on the scope,(a round figure) and then it was 16.6666ms, harder to square down on the screen. However, having worked all these years as an industry consultant, I have been asked a zillion questions regarding how a 50 Hz motor will run on 60 Hz, how to calculate the new performance, and how to adjust phase-controlled, 50 Hz magamps, M-G sets, Thyratron or SCR drives to run on 60 Hz. Last question on this topic was less than one month ago.

My advice? Leave things as they are, or as we say in Venezuela: "deje quieto al que esta quieto", which, roughly translated, means: "leave alone the guy who is sitting still".

Hope my country's experience will help...

There is certainly a good measure of verdad in that truth.

Probley not the answer you are looking for but in the 70s and 80s I was a musician. Most AMPs at that time were tube rather than Transister ( And there is a lot of argument as to what is best for that kind if use ) But here is the thing. When we heard new music that was something that inspired us we could usually tell if it was recored in the US or GB as these two countries is where 95% of Markatable music comes from. But if you listen carefully you can hear the hum of the AMPs and the PA system and the recording systems in those days. Filtering out the hum is done with noise canceling systems for that. But I know what 50 Hz sounds like and I know what 60 Hz sounds like. A good example is to listen when someone is welding with an AC welder in the US or GB. The tone will be different in each but will stay in my mind if you dwell in it for a moment when you are listening. So. One good thing about having both 50 in part of the world and 60 in our country is we know where a recoding was made just by listening carefully to the hum. Cesare

About one third of the worldwide electrical power consumption is at 60 Hz (20% corresponding to the US alone).

Also 15% of the population is served by 60 Hz.

I have not been able to find this on the web, above results were calculated based on available tables for power consumption, frequency and population for each country. Japan was taken as 50-50 for lack of information, probably consumption at 50 Hz is higher.

Corrections welcome.

brgds

Snel

I did remember some more about this topic. I have a grand memory, but a coupla small TIAs played havoc with the retrieval algorithms.

60 Hz came out of East Pittsburgh's Westinghouse Electric plant in the late nineteenth century. George Westinghouse's brother, Herman, had built some generators running at 133-1/3 Hz. Westinghouse had a very good engineer, name of Shallenberger, who had been doing some work with induction motors, and Westinghouse also brought in Tesla about that time. They pretty quickly came up with these criteria:

• the frequency needed to be above 50 Hz so that arc lights wouldn't have an objectionable flicker;
• whole numbers just seemed better to everybody;
• because of the electric steel of the time, and especially because many of Westinghouse's motors used single cast cores instead of laminations, core losses were unacceptable near 133-1/3 Hz;
• Tesla had already worked out (Ferrari said "copied") the design for 60 Hz polyphase motors.

So, when they cut 133 -1/3 Hz in half, and rounded down to 60 Hz, they found they had a number with acceptable core losses, no light flicker, and one that was easy to do with simple numbers of poles at 1800 RPM. And, it made Tesla happy, as well as gave Westinghouse a distinctive marketing point.

After the first thousand motors or so, it was like the story of VHS vs Beta. First to market usually wins.

If we were doing all this today, we would probably choose something in the 400 Hz to 1000 Hz range.

"...today, we would probably choose something in the 400-1000 Hz range."

Is that because of the way it is done in aviation, and core losses were overcome?

We have inexpensive steel that works at 400 Hz because of aviation, and powders that work past 1 kHz. Just pickin' a coupla numbers that came to mind.

I learnt from your post and I agree with your post, as it all "hangs" together very well in what you said and is simply far more than "possibly" correct I feel, thanks.

I myself do not see pulsing from 50 or 60 Hz lighting or computer screens or anything (its a blessing in disguise!).

But I know people who do, mostly younger than me, though I don't think its an age problem. I had a screen on my company PC years ago that certain people could not look at for such reasons, I simply could not see what they wee talking about!! Though I did believe them by the way!!

I had to, from time to time, design additions to computer equipment that had to work in areas where strong fluorescent lighting was in use, it was amazing to me just how much I had to filter certain sensors (over and above that of my original design!) to rid myself of 50Hz fluctuations, naturally once you looked at the resulting signals on a scope.....some tube manufacturers were worse than others, possibly I believe due to a lack of persistence in the powders, cheaper I expect....though that is just a guess only.....

The pulsing is there, no matter whether 50 or 60 Hz I have found and as you already mentioned, 400Hz would have been a far better choice, if the technology of more than 100 years ago had allowed it. Its as simple as that!! But it didn't!!

Thanks for your post.

TV and Movie frame rates are typically not more than 30 frames per second.

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I suspect the problems that were common with computer screens was probably often due to the frequency of the florescent tubes with magnetic ballasts being slightly more or less or cycling above and below twice that of the computer screens. The resulting beats could be perceived as flashing in a much more readily noticeable frequency range.

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It really should only be fluorescent tubes running on magnetic ballasts causing flashing at twice supply frequency. Phosphors produce light for a period longer than electronic ballasts cycle, so there shouldn't be flicker with electronic ballasts.

couldn't you see pulsing even when entering a TV store [in a 50 Hz country]?

A whole wall covered with TV sets, all working, was hard to bear, especially when seen peripherally.

Of course this was before 100 Hz vertical scanning.

Snel

I really don't see it, whether or not other parts of my brain react to it I cannot say, but I never got headaches or similar, whereby colleagues would walk out of my room about 15 years ago after one look at my computer screen, it almost made them sick.....

I could not even see the problems with the eyes even when not looking directly at the screen (you understand what I am talking about I hope!)....

I had good definition, many years ago an eye doctor was impressed when I showed him that with my glasses (after I was 50), I could read the test card and even had a good go at the printer's name!!

He said whereas the standard for cameras was 1 Mega Pixels (then), he likened it to average people's vision, I had the equivalent of 4 Mega Pixels.......I wonder what he would say today?

But reaction speed, always Slow.....not a bad thing I feel.

Humans can not normally see flicker below 20 Hz. Some can but not many. A good example is the Computer Monitor at 60 to 75 sand TV at 30. Now this is the old Jug or cathode ray tubes. Now. SMPTE Society of Motion Picture Engineers standardized on 24 frame per second as you could not see the flicker and the slower the frames per second the shorter the real of film and the more time per real kept costs and weight down. Now. The goal is to move from film to Lazers that draw RGB on the Movie Screan and the plan is to standardize TV and Movies to be the Same and that standard will be 48 hz or Frames per second. So Back to the bulb in those days. It would take too long for the filament to cool down. even with newer bulbs it can take more than 1/4 of a second to start to see the light diminish after cutting the power. So again I do not think there was any noticeable flicker with a hot heavy filament. Does anyone concurs?? Now to the main question There are good and bad points for both. However. I do not think that 50 Hz was causing flicker. Why. Well I have some very old bulbs that were in my grandmothers battery house where the batteries were kept for the phone system. These were the old glass Jars with Lead and Zink Plates and what looked like the color of cardboard. Some kind of pressed paper. Then those jars were filled a little past the top of the plates with Acid ( Most likely Sulfuric )and on top of that was oil. The oil to keep the water in the electrolyte from evaporating. Those batteries are still there and they still work. Not used for the phone anymore but they work. Anyway in that same building or shed there were fuses of all kinds and packages of very very old light bulbs. Some of the Bulbs were for DC so Great grandfather must have had a Generator somewhere. And keep in Mind. Most cars used DC Generators up until the 60s. Up to the late 60s for Harley Davidson MC. Since the Radio required more Voltage it had what was called a Viberator so as to pulse the current for the transformers. Now I took one of the very old bulbs that were for AC 110 ( Note it said 110 V and not 120 V. They did not say DC on the bulbs unless they were DC like some of the car lights ). 6V DC. I real driving or riding in cars with this setup. Anyway the filament in the old bulbs was very heavy compared to the same type of bulbs at this time. And I sure you all know that you can run DC on an AC bulb ( Filiment type ) but you need to drop the voltage or Amperage or both. Sorry for babbling on. It is just how I talk when writing. But still I do not think there is any big advantage to 60 over 50 or 50 over 60. Nothing to get in a tiff about. I think the Beta vs VHS comparison someone else made is a good one. But Beta was in Fact first. In Fact Sony created Beta ( The first 1/2 inch helical scan Video system. Sony would Not share or license the technology to ANYONE. 3/4 inch and 1 inch and 2 inch were common but not practical for hime use. Victor Company of Japan Got upset that Sony would not share so they came out with VHS. You only have to change the design by about 15% to get around most patents. Victor Co Of Japan was known and is known and JVC. JVC decided to share the technology with all of the other TV MFG companies and that gave them the market edge even after Sony decided it would have to license as well. So the ware continued and VHS won out for many reasons in most of the world. It even got to the point that SONY made and paid for the license to Make VHS after a few years. So the example that was given is correct but backwards mostly. Jim Davison

That may be more true for filaments, but I was talking about fluorescent lighting, that is a big difference, especially when you look at a light sensor using a 'scope!!!

Most (in my estimation) industrial lighting is not filament.....though even then, one can still see/read the frequency with the correct equipment....but the eye is fooled....

Using ancient light bulbs or whatever is not quite what everyone does nowadays to stop falling over things in the dark at home.....

Have fun!!

I fully agree with you. However the idea was what is the advantage of one over the other and a lot of posts were talking about when Tesla was still around and how they came to use 60 HZ. Then posts about seeing flicker. In those days fouresent tubes did not exist. Nor did computer monitors. Now. We can not see a flicker at 50 hz. A fouresent in bad shape will flicker but not at 50 HZ. They flicker due to loss of gas in the tube thus not all power from the ballast is discharched. In some cases I have seen them flicker at rates of less than two times a second or even one time per second. WE did learn that for Movies and TV we have to have frame rates above 30 frames per sec on thus 30 hz to stop folks from having seizures. 48 Frams per second will most likely be the new standard and many new Movies are being recorded at that rate to future proof them. But we all know that even with 60hz fluorescent tubes give us headachs and cause other problems. Our eyes can see the flicker as well as the optic nerves but our brains do not perceive the flicker at those speeds. But it does cause stress and is in a lot of opinions not good for a persons and I also do not like to be around flouresent tubes. With the old computer monitors using Jugs rather than the new flat screens the 50 and 60 Hz gave folks headache just like florescent tubes. So the later models and the Video cards and frame buffers on the cards could be set to 72 for example. That was found to stop the headache and shown on a Camera and TV screen a 60 Hz Monitor would flicker on the TV that had a camera pointed at it. Same with putting a fan in front of a TV and or forewent tube. So I get your point and fully agree with it. 60 Hz is bad news as far as Light sources. But with a filament the filament will not cool and heat as fast as the 50 or 60 Hz so it is not flickering. Even with high speed cameras you can not see the flicker other than when you first turn it on. Also Compact Flourecent tubes have a capacitor in them to keep them from flickering. With fluorescent Tubes the large ones they flicker in part to save on power. They are in fact off half the time. They flash on and off but are off half the time but still give us the same amount of light for practictical reasons if you leave headache out of the equation. So again my point was simply when the original decision was to go with 60 over 50 etc.. the only lights around at that time were filaments and heavy filaments at that. Lighter material did not come round until much later and even they do not have time to cool enough to flicker. And to point out we can not see it. Even in fouresent but it can cause headache and if the fouresent tube and or ballast is bad you can see a flicker but not at 50 or 60 hz. It will be much less before you see it. And is not caused by the frequency of the AC power but by a weak tube or ballast or both. Thus my point is I do not think that tesla decided that 60 over 50 was to stop flicker. I bet it was to have a different speed as they already had a contract to fill. Jim

One post mentioned flicker of arc lights, I presume this refers to "lime" lights. At any rate, your post is interesting on a number of levels, especially in consideration of the "ban" on tungsten bulbs in favor of these ridiculously expensive and practically worthless compact fluorescent bulbs. I hate them. I will happily go after LED bulbs if (1) they come down in price just a bit more, and (2) someone can prove that flicker headaches do not take place with LED bulbs. I suppose they incorporate a full wave rectifier, with at least a modicum of 60 Hz/120 Hz filtration in the form of a capacitor?

The LEDs are down quite a lot. At Several larger Hardware stores they are now below $10 for one that is = to 60 watts of filament bulbs and up to 13.99 for a 100 watt equvalanet. And they are available in several colors (degrees K Not RGB ). So they look better than they used to and they also are softer light than they older more costly harch light that is nice for reading a schematic but useless for normal household light. But Can I ask. Why do you HATE the CF bulbs. I have only CF and now a few LEDs. I very much like CF. They do not flicker. I used a simple variable speed fan to confirm after I read that they did not flicker and give headache etc.. I purchased my first CF in the very early 90s. I was poor at the time and wanted to save on power and I am one that likes a bright home at night. So my power bill was high. Mostly in the winter with long nights. Anyway I could afford only one per month and I was so happy when I got all bulbs in my 2 bed 2 bath home all change from filament to CF. I had severl brands. Fiet was the first one and I still have that same bulb and it still works. It is on my back porch lighting the way from the garage to the house. It is now 23 years old. Anyway when I got all bulbs changed in the first house I was very happy that wilt EVERY light on in the house I was using only 280 Watts. Before the CF if I had turned them all on at the same time it was almost 1800 watts. Thus I never did. They come in all kinds of color including daylight and I like them. In Fact I met the man that designed them. Am still trying to get him to sell me a patent on a very cool technology he put together for Neon Lights but he does not want to part with it or use it and he is old so I guess it will die with him. Anyway I also very much like HIDs for my cars. Am trying to find if any aircraft maker is going to start using them for Landing lights. The current ones get so hot to light up a runway with a filament and they burn out at just the wrong time. I like the LEDs but I do not hate the CF. But would like to know why you hate them so much. Is it the mercury or what?? Jim Oh yea. Even with Arc Lights you can not see flicker at 50 or 60.But it is a good way to get sunburn or I should say Arc light burn if in front of them for long. they put out too much UV. As does a welder. Jim Davison

I have never taken a tungsten bulb out of the package to install it, only to find it does not work, but I have with CF's. You are having a lot better luck with them, as to life, but we switch our lites on/off quite a bit (probably uses more electricity in the long run). I do not like the fact that when I want light right now, at the level I want it at, I get this dim glow that gradually increases (five minutes later) to what I wanted, but it is not the right color temperature to suit my mood (which is apparently dark as I write this).

I do not like CF when wanting to use the dimmers I installed in the master bathroom for the purpose of having light without waking up the dragon (wife) in the morning.

"Each-buyer" is a good source of cheaper LEDs, slightly longer delivery times due to coming from the far east, I have a lot of them in my house....

Some CFs are all wound or twisted over themselves.

What happens to the light that is emitted towards the center and hits the opposite glass tube stretch? Little reflection. Is this considered when boasting the efficiency figures?

Try an IR receiver diode under good/normal fluorescent lighting, look at the output on a scope, the frequency of the supply is quite obvious....

Switch the lighting off and on just to convince yourself that its not simply a noisy power supply on the LED circuit.....though a battery driven one would be better on that score...!!

My eyes do not react to even quite low frequency pulsing.....thankfully.

On the older Florecent with the ballast you are correct. Part of the way they save $ for usage is the fact that they are off half of the time. On Off On Off 60 Times a second in the US and 50 most other places. OR at least most of Europe. Personaly I am like the fellow that does not like CFs when it comes to long tube ballast based lighting. I just hate those and they make a lot of folks have headache and they in my opinion cause eye strain and give the optic nerve one hell of a workout. Just not good for humans vision system. I have no use for them and can get more light for half the power with a CF of a LED. I do love the LEDs. I never have checked if the LEDs flicker. I assume not as I am not bothered by them like I am with Tube Ballased based Fluorescent Jim

I never actually checked what type of ballast was in use as I also don't know when modern ballasts were first introduced.....

Somewhere I have IR detectors, its finding them that will be the problem. If and when they are found, I promise to make tests and post the images.....but don't hold your breath.....

But as I know from that time when I was making these changes to certain computer equipment, that the detectors still detected the frequency even when only using filament bulbs, reduced but still visible.

I would not personally be surprised if even with modern ballasts and tubes the frequency effects will still be visible, maybe at 100 or 120 Hz (just guessing though!!) as I have never looked inside a modern ballast....but I have no proof either way today.

Maybe someone else here has the possibility to test further....

I know where my IR detectors are, problem is to repair my scopes...

These ballasts operate at some tens kHz, but the phosphor persistance won't let you see the "carrier", only the "modulation" at 100 or 120 Hz. Maybe if you detect the leaking UV...

Older electronic ballasts had a lower "optical ripple". Now they are power-factor corrected, so the blinking is back.

Andy: Having worked in a darkroom in high school, I learned how to get around in the dark quite well, but everyone makes fun of my funny shaped ears, and my high-pitched shrieking?

Actually, we always have at least one lower light burning as the old hymn states. The "poor soul who may be sinking" could be myself stubbing a toe on a chair the wifey moved right before bedtime into my path. (She is a former Church of Christ minister's wife, so I rightfully expect stumbling blocks from here on a regular basis.)

What is needed in the world is not so much a better light source, but a better source of power in the first place. I tend to agree with posts that mention higher frequencies, but I cannot imagine the world generation fleet changing this any time soon. Can you imagine what this would entail? Another concern: at those higher frequencies capacitive coupling to earth ground increases, so transmission losses would skyrocket. The only way to surmount both obstacles is this: convert the power to a suitable frequency at the point of use, or simply convert it all to DC at the point of use, either way all appliances would have to change to match that. What a freaking mess!!

Well I agree a new source of power is a great idea. I hate the idea of bunting coal for power. I do like heating my home with it. I used to until it was made against code in the great communist state of California. But there are far far better ways to heat. I personally like Hydro power. The Granola Heads try and tear out all DAMs as say they polute more than a coal or oil power plant. That is Horse Shit. They will say things like plant mater from tress meaning leaves fall into the water behind the dam and then rot. Thus causing gasses. Well. Guess what. That same process happens when it falls on the ground. In fact it happens faster and gives off more gas. Kind of Like Folgers coffee used to advertise that its coffee was mountain grown. And it was. but so it all other brands that are fit for consumption. Those plants need more UV A B and D is one of the reasons. So by omission they lead folks to think that Nuclear and hydro are bad news. If you interview protesters of most power plants you will find they are not the sharpest knives in the drawer. ( Sorry I do not spell very well ) . And many get paid to protest. And if you follow the $ who has to gain from no Hydro and nuclear power? Anyway the new Thorium Nuclear would be very cool to make cheap and safe power. We are only using about 1/3 of the potential Hydro power and you do not have to ALWAYS make a DAM to make hydro power. But DAMs do a lot of good if build well. Even for fish. And it is very easy to control the speed of the Alternators at the dams. Now. You said we should use DC. As you know everyone will say that DC is no good for long distance and that is why AC was addopted. But I never understood this. I used DC and ran DC lines for hundreds of feet and did not get any more lose than AC. Also The States of WA OR and ID make a lot of hydro power. They connect the output from a lot of DAMs to a grid owned mostly by Bonaville power Administration. Used to be a federal ORG now private. Anyway along the columbia river there is a town called THE DALLS OR. That is where the grids lines connect. And that is where a Line runs Non Stop from the Top of OR to LA CA. Now. To save on $ to Build this long non stop line they used DC Rather than AC. The idea is AC is off half the time thus you get almost two times the power over the same gage conductor with DC. Now that is a distance of about 700 Miles. I read that DC could not get from Niagra Falls to Rochester NY. That is about 50 Miles if I recall. Maybe less. Thus again the other reason for AC. The DC line from OR to Los Angles is very efficient even though they have to convert AC to DC in OR and Back to AC in LA. So Not sure the deal with heavy losses on DC over long runs. That line is at 750K Volts. Not sure how many MW it transports if you can look at power as something that is transported. Why are you in a Dark room. I thought everyone went to digital After the new CCDs Made the RED CAM possible. Why use Chemistry now??? What would be the upside??? Jim Davison

Electric transmission facts: P = VI power transmitted to load in network (the current I is shifted from potential V by the phase angle, and is a complex number). Typically increases in inductive loads (motors typically) results in a lower power factor, phase angle increasing (voltage leads current in inductors), but an increase in VAR and Power loading in the system. Transmission losses are as P_L = V_LI, where V_L is voltage loss over distance traveled. This is also stated as P_L = I²Z_L, where Z_L is line impedance.

Z_L = R + jωL + 1/jωC, where R is ohmic resistance, L is reactance, and C is capacitance, with j as imaginary unit vector (square root of -1) and ω is line frequency. It has been found that for normal transmission lines, as AC voltage is increased, there is an increase (at some point) in capacitance to ground, resulting in a lower impedance to ground (so-called radiative losses), this is because air has a finite dielectric constant, insulation bushings also model as a capacitor (of low value), etc. With DC transmission the only factor to consider is R, which is there anyway, but as V increases, the current draw is less (and with constant R, there is less overall line loss), thus some power is transmitted at extremely high DC potential, over long distances with less loss overall than would AC of a slightly lower potential.

I am aware that higher frequencies seem to exhibit higher losses due to radiation effect.

"SMPTE Society of Motion Picture Engineers standardized on 24 frame per second"

in fact it's 24 photograms / s but 48 frames /s (each photogram is illuminated twice).

brgds

Snel

Most folks that are Not in the industry hear or understand Frames. So outside of the industry and even inside the word Frames are still used. Now. Recording in 48 Frames per second is in fact what is in the works to be a standard so most Movies and some TV Shows are using that rate to record and save the Master file. However there is NOT a Television that will display at that rate yet. Not even Ultra High Def or as the public knows it 4K TV. But to save on Storage space and or transfer rates I am not aware of anyone using the same photograms twice except in the case of HI DEF TVs that are displaying older NTSC 30 Frames per secant then every few frame one of them is displayed twice. And in Cases were test Sets at factories that have the ability to decode 48 frames per second but do not have the speed to display 48 will do as you stated. So yes that is the case but not on the market at this time. It is coming though. The main reason is SMPTE's Biologists discovered that with 3D folks get ill and headache watching it. However they discovered that at 48 Frames this effect is eliminated. And it also Helps with normal 2D Images. Even if made a standard it does not stop the older technology to use it. So the Movie is recorded and edited in 48 but after all is done and the master file is made for the Movie a trans coder will convert the file ( In this case file = Movie ) to 24 Frames and at different resolutions. One for DVD and one for Blu-Ray Etc... etc.. Also I do not want to sound smug. But SMPTE is Society of Motion Picture and Television Engineers. ( You left out "And Television ) I am a member but do not claim to know everything about all the standards. My company has to do with High speed networks and cross platform networking and also doing what we already did for the publishing industry and that is to offload as much of the work as possible from the work station and put it on the server. But the main thing is you get the idea about two frame or photo grams being shown two times. The whole idea is to get to higher frequency as it is better for us and the reasons for this are similar or at least in part related to the 50 V 60 Hz issue with AC Power. Jim Davison