Can I still get 100w bulbs?

[JohnW2]

Going very slightly off topic. Fluorescent tubes can make a spinning circular saw blade look stationary. I wonder if any LEDs flicker at the same frequency.

If the LED lamps/bulbs are cheap ones (with just a capacitor and bridge rectifier to control current) then any flicker will be at 100 Hz,the same as a fluorescent tube, but if they have was is effectively a SMPSU, then it could be a much higher frequency.

The difference is, of course that, whatever the frequency, a smoothing capacitor can be used to reduce the amount of flicker (theoretically,to any extent one wishes), whereas with a fluorescent tube with a traditional 'magnetic' ballast, the only thing reducing flicker is the 'persistence' of the phosphor with which the tube is coated. I presume that 'electronic ballasts' probably resulted in much higher frequency 'flickering'.

Kind Regards, John

 

[opps]

If the LED lamps/bulbs are cheap ones (with just a capacitor and bridge rectifier to control current) then any flicker will be at 100 Hz,the same as a fluorescent tube, but if they have was is effectively a SMPSU, then it could be a much higher frequency.

The difference is, of course that, whatever the frequency, a smoothing capacitor can be used to reduce the amount of flicker (theoretically,to any extent one wishes), whereas with a fluorescent tube with a traditional 'magnetic' ballast, the only thing reducing flicker is the 'persistence' of the phosphor with which the tube is coated. I presume that 'electronic ballasts' probably resulted in much higher frequency 'flickering'.

Kind Regards, John

You may well be correct. After digging deeper, I discovered that some twin fluorescent tube fittings were designed to oscillate out of phase, thereby not making table saw blades look stationary.

 

[JohnW2]

You may well be correct. After digging deeper, I discovered that some twin fluorescent tube fittings were designed to oscillate out of phase, thereby not making table saw blades look stationary.

Interesting idea - which I've never heard of - but, at first sight, I can't think of how that could be achieved.

Kind Regards, John

 

[opps]

Interesting idea - which I've never heard of - but, at first sight, I can't think of how that could be achieved.

Kind Regards, John

Post number 7, from this site, talks about lag twin bulbs

Flourescent lights & circular saws

Fitting some fluorescent lights in a workshop tomorrow for a chipie. I thought I heard somewhere that if you have fluorescent lights on, when using, say, a circular saw, it looks like the blade isnt going round. Anyone else heard of this ?

www.diynot.com

 

[Ragnar_AT]

Yes, electronic ballasts are supposed to push the frequency far up into the kHz range, rendering it invisible to the human eye.

In countries that commonly supply three-phase to homes and small businesses it was recommended to spread fluorescent lights with wire-wound ballasts across multiple phases in rooms with spinning machines to avoid strobe effects. In larger workshops that was considered a necessity anyway because of the large reactive currents that lowered the number of lights per circuit quite drastically compared to resistive loads. I remember frequently consulting with an Osram brochure that contained load tables for all sorts of fluorescent and discharge lights when I worked in electrical planning about 20 years ago.

Around that time LED emergency lighting became a thing and it was a godsend for reducing backup battery capacity in large industrial building compared to the usual 400 W discharge shop lights!

 

[opps]

Plenty were, but even there replacing with LED is at least at 50% reduction in energy use. More in some situations.


Yes. Electricity consumption down almost every year and in every sector.
There are efficiency improvements in most areas but lighting is by far the most dramatic.

View attachment 329641
source: https://assets.publishing.service.gov.uk/media/64f1fcba9ee0f2000db7bdd8/DUKES_2023_Chapters_1-7.pdf

I only briefly scanned the PDF, but it doesn't say that the shift to LED lighting has been the main driver in consumption dropping.

Other articles suggest that lighting in domestic properties (globally) only accounts for 4% of domestic consumption. If we assume that LEDs use 75% less electricity, 75% of 4% is only 3%- would that explain the drop of 19% in domestic usage since 2010?

According to an estimation by the International Energy Agency (2016), the residential sector accounted for 21% of the final energy consumption worldwide in 2013. Although there are considerable variations in energy usage across countries, on average, households use 52% of energy for space heating. Compared to the share for space heating, the share of energy consumption for lighting is relatively small and accounts for only 4%.

Granted, some countries/continents will have different lighting requirements, but might it not be the case that improvements in heating systems and insulation have had a bigger impact than lighting?

 

[Ivor Windybottom]

In addition, almost all appliances are now vastly more efficient than in the past. The older appliances take lots of years to get replaced, sometimes decades, so things take time to improve.

E.g. there was a ridiculous power battle among vacuum cleaner makers once, they were proudly boasting the consumption and printing it in massive numbers as being a pseudo performance indicator, most of which was emitted as heat. The EU ended this stupid war by limiting them to a maximum of 900W in 2017, forcing them to improve efficiency instead.

Many TVs used to consume almost as much power in standby as they did when on. This was also forced to be improved.

I calculated that our old oven was costing us about £50 a year just to keep its clock lit up. So we got into the habit of switching off at the wall between uses. No doubt newer appliances aren't so wasteful.

It's very difficult to attribute any single cause to the drop in consumption, unsurprising as there isn't a single cause. But it's obvious that any household switching from filament bulbs to LEDs will definitely save a substantial amount per year, probably covering the cost well within a year.

The wasted energy does heat the room, but this heat is still 3x more expensive than the heat from gas heating or an electric heat pump. Also it's only welcome heat when it's cold, it's a disadvantage in the summer - especially if you have air conditioning, in which case you're paying again to get rid of it.

 

[flameport]

, but might it not be the case that improvements in heating systems and insulation have had a bigger impact than lighting?

Not in the UK - most properties are heated with gas or oil, so electricity use is unrelated.
Insulation improvements have been stalled for the last 10 years because a previous PM decided to 'cut the green crap'

Other articles suggest that lighting in domestic properties (globally) only accounts for 4% of domestic consumption.

Probably true in some places at some times.
Massively depends on the property - if it's a single pendant in each room, lighting use will be small.
However with the massive overuse of downlights in every room, electricity use would be vastly higher as a percentage, such as kitchens with 20x 50W halogen lamps in.

Commercial/industrial installations will be a much higher percentage as lights are typically on for extended periods including permanently, and there are a lot more of them.
They are not all fluorescent to LED conversions either - plenty of retail and hospitality venues used vast amounts of incandescent and halogen lighting until only a few years ago.

 

[Ragnar_AT]

Of course! My guesstimates were based on an average of 75 W per room (all rooms, including hallways, loos, etc.). Replacing the 60 W incandescent in my lounge pendant with a 6 W LED and the 40 W incandescent in the reading light with another probably didn‘t do much to reduce my electricity bills. Living like that myself I tend to forget that there‘s people who have chandeliers with 15 60 W incandescent lamps in their lounge chandeliers (not exaggerated, I saw that once). Likewise, my gran had a boxy glass light in her lounge that I‘d expected to have four 25 W lamps. Much to my surprise I discovered four 60s when I replaced the light.

 

[JohnW2]

.... I tend to forget that there‘s people who have chandeliers with 15 60 W incandescent lamps in their lounge chandeliers (not exaggerated, I saw that once).

I can't quite compete with that, but (as I've probably mentioned before) I have a pretty unusual large kitchen (which is trying to be 'period' ) which has 5 x 3-lamp fittings, plus 3 single lights, not to mention a few 'cupboard lights' - so more than 18 in total. Once upon a time they were all 25W incandescent candle bulbs, hence 450 W. However, for a good few years now they have all been 3 W candle LEDs - hence a bit under one-eighth of the power of the incandescents.

Kind Regards, John