your workshop - whats the best lighting?

[jonbikebod]

I mentioned the strobe effect of fluorescents in an earlier mail. The reason they flicker is the phosphors get excited 50 times a second because that is the frequency of the mains. I double fitment will therefore have the two tubes flickering at exactly the same time and not really improve matters. The reason a filament bulb lamp works better is the filament get heated 50 times a second but stays glowing in between (called persistence). Phosphors react more quickly and this is why they are used in the tubes of (older) TV sets. If they didn’t respond quickly, a moving picture would be blurred.
Jon.

 

[Adam]

I mentioned the strobe effect of fluorescents in an earlier mail. The reason they flicker is the phosphors get excited 50 times a second because that is the frequency of the mains. I double fitment will therefore have the two tubes flickering at exactly the same time and not really improve matters. The reason a filament bulb lamp works better is the filament get heated 50 times a second but stays glowing in between (called persistence). Phosphors react more quickly and this is why they are used in the tubes of (older) TV sets. If they didn’t respond quickly, a moving picture would be blurred.
Jon.

I have to admit I thought the "strobe" effect of fluorecents was only true years ago, - and that for many years now, electronic ballasts now excite at such higher frequencies that no strobe is visible. I've used flourescents as the sole light source in my workshop and never seen such an effect on lathes, electric drill, routers, table saw etc etc.

As far as I know, all modern compact flourescents (as replacement for regular filament bulbs all use electronic ballasts.)

Electronic ballasts usually change the frequency of the power from the standard mains (e.g., 60 Hz in U.S.) frequency to 20,000 Hz or higher, substantially eliminating the stroboscopic effect of flicker (100 or 120 Hz, twice the line frequency) associated with fluorescent lighting (see photosensitive epilepsy). In addition, because more gas remains ionized in the arc stream, the lamps actually operate at about 9% higher efficacy above approximately 10 kHz. Lamp efficacy increases sharply to about 10 kHz and continues to improve until approximately 20 kHz.[1] Because of the higher efficiency of the ballast itself and the improvement of lamp efficacy by operating at a higher frequency electronic ballasts offer higher system efficacy. In addition, the higher operating frequency means that it is often practical to use a capacitor as the current-limiting reactance rather than the inductor required at line frequencies. Capacitors tend to be much lower in loss than inductors, allowing them to more closely approach an "ideal reactance".

 

[Richard Findley]

Hi Adam,

I must admit that I've never actually tested out the strobe effect that I mentioned as my workshop already had double tubes fitted. I guess when a college lecturer tell you somthing you don't really question if the information is out of date

I left college about 10 years ago so not sure if the lecturer was correct at the time or not :?:

Richard

 

[jonbikebod]

Good point Adam. I am not sure how wide spread electronic ballast use is. I bought the ones in my workshop two or three years ago from one of the local shads. The certainly have a heavy block at one end which seems to vibrate at mains frequency. I didn’t take it apart to see if it was a wire wound ballast but that was the impression I got. I would guess that many workshops will be utilising ‘second use’ fitments as well. Can we agree that if you can hear them hum they have the potential to strobe?
If you read my original mail you will understand why I tend to be extra cautious.
Jon.

 

[dickm]

The forum has been through this strobe idea before! Personally, I can't see it being a real problem. To get a strobe effect, the rotating item has to have spokes or something similar (teeth of a saw blade, jaws of a lathe chuck, say) that are uniformly spaced apart, and the strobe effect will only occur at speeds that are exact multiples of 50cps and the number of "spokes".

Readers old enough may remember that up-market record turntables used to have repeated patterns round the edge to use the strobe effect to make sure they were revolving at exactly 33and a third rpm.

 

[PowerTool]

Readers old enough may remember that up-market record turntables used to have repeated patterns round the edge to use the strobe effect to make sure they were revolving at exactly 33and a third rpm.

Ahh,good old strobosynchroscopes - on my old record decks,had them for 33 1/3,and 45 rpm (for anyone much younger than me,this was in the days of vinyl,before the advent of the CD :lol: )

Andrew (pub DJ back in the Eighties..)

 

[exigetastic]

I currently have a halogen worklamp.... the light is rubbish, but at least it warms up the shed

Though as soon as I get the electrics sorted I'll be putting in some flourescents.

Si

 

[Nigel]

Matt there is a big difference in the light output of full spectrum tubes as apposed to standard daylight tubes they are much brighter and give a clearer light to be able to distinguish colours,
They are used in the various trades for colour matching and really give the impression of daylight and are a delight to work with if no natural light is available,


Cheers Nigel