Fluorescent tubes -> LEDs?

[ericmark]

Ballast describes the device, not its function, as does transformer, so an electronic device which replaces them is some sort of switch mode power supply not really an electronic ballast or electronic transformer, although with the latter it still transformers, but we would not call a battery charger a transformer even if it does transform the supply from 230 volt AC to 14 volt DC.

 

[Harry Bloomfield]

Ballast describes the device, not its function, as does transformer, so an electronic device which replaces them is some sort of switch mode power supply not really an electronic ballast or electronic transformer, although with the latter it still transformers, but we would not call a battery charger a transformer even if it does transform the supply from 230 volt AC to 14 volt DC.

Got you - they are in fact a rather specialised switch mode power supply SMPSU, but they are commonly referred to as an e-ballast. Just as the SMPSU's used for 12v downlighters are wrongly referred to as 'transformers'.

 

[JohnW2]

Ballast describes the device, not its function....

Maybe! Does anyone know how this seeming rather odd word came to be used to describe such a device, if not also its function ("ballasting"? ).

Is the word used similarly in any context other than fluorescent lighting?

Kind Regards, John

 

[Harry Bloomfield]

It's other name is a 'choke' it chokes the voltage, or drops it once the tube strikes, they also long ago used a resistor for the same purpose. A choke in electronics, following a DC power supply, prevents or rejects the ac but allows the dc through.

Other than that, ballast is put in a ship, to make it sit deeper in the sea, or counter-balance the pull on the sails.

 

[JohnW2]

It's other name is a 'choke' ...

"choke" is a very long-established generic term for any series inductor, and that is exactly what I would call the things in fluorescent fittings were it not for this "ballast" word Every DC power supply I built back in the 60s had a choke as part of the (50Hz or 100Hz) smoothing, and I used "RF chokes" very extensively in those days.

However, none of this explains how/why (or even when) the "ballast" word came to be used in this context! As you go on to say ..

Other than that, ballast is put in a ship, to make it sit deeper in the sea, or counter-balance the pull on the sails.

Indeed - none of which has even a remote connection with an inductor/.choke used in sn electrical context.

Kind Regards, John

 

[Harry Bloomfield]

"choke" is a very long-established generic term for any series inductor, and that is exactly what I would call the things in fluorescent fittings were it not for this "ballast" word Every DC power supply I built back in the 60s had a choke as part of the (50Hz or 100Hz) smoothing, and I used "RF chokes" very extensively in those days.

However, none of this explains how/why (or even when) the "ballast" word came to be used in this context! As you go on to say ..

Indeed - none of which has even a remote connection with an inductor/.choke used in sn electrical context.

Kind Regards, John

My best idea is ballast in a ship = heavy weight, and early ballast were certainly quite weighty.

 

[Harry Bloomfield]

You obviously like technical puzzles, I have a curiosty from around 50 years ago. Around 1971 making my way down to Penzance, which is a very long drive from here where I live, in a Triumph Dolomite. I was on route to my holidays setting off straight from work and got to (I think) Bodmin Moor around 2am and decided on a kip in the back, parked up out in the wilds and quite tired and a dry evening/ morning, absolutely black.

Whilst manouvering inside - engine off, road lights all off - I happened to catch the horn button and the entire windscreen glass flashed up what seemed to be in complete blackness, a bright florescent blue. I tried it several times and each time it did the same, whilst ever the horn was pressed - bright blue.

 

[ericmark]

Is the word used similarly in any context other than fluorescent lighting?

Yes, with 110 volt traffic lights when first the new law came out requiring vehicle sensing the GEC micro wave detector (RADAR) required 55-0-55 volt, Mullard would work with 110 volt. So the 110 volt generators needed altering to provide 55-0-55 volt it was 110 volt with no earth i.e. IT.

So the unit I would have called a auto transformer was called a ballast by Forest City who made the portable traffic lights, it was short lived, as using a PEN from the controller to traffic light head caused problems when the PEN was lost, one could get 55 volts from traffic light head to true earth, and it seems 25 volt can kill a cow, so the ballast was fitted inside the RADAR head to give the centre tap, so no current flowed down the earth wire. Think talking about 1977 or there about, we still used the generator from earlier sets all though one depot still had a set of gas traffic lights, seems they never worked very well, mantels kept breaking and they would go on fire, the new law allowed them to be scrapped without any red faces.

 

[JohnW2]

My best idea is ballast in a ship = heavy weight, and early ballast were certainly quite weighty.

Hmmm. I don't buy that one

In every one of those PSUs I built back it the 60d/70s, although the smoothing chokes were certainly fairly big and heavy (often heavier than the ballasts in fluoro fittings), the associated transformer was invariably much bigger and heavier - but they were still called "transformers" (not "ballasts"), despite its weight

Kind Regards, John

 

[JohnW2]

Yes, with 110 volt traffic lights when first the new law came out requiring vehicle sensing the GEC micro wave detector (RADAR) required 55-0-55 volt, Mullard would work with 110 volt. So the 110 volt generators needed altering to provide 55-0-55 volt it was 110 volt with no earth i.e. IT. ... So the unit I would have called a auto transformer was called a ballast by Forest City who made the portable traffic lights ...

Fair enough, but that's an anecdote relating to a very specific and specialised area, about which I doubt that manufacturers, sellers and users of fluorescent light fittings would have known anything - so I don't think it can explain how the word "ballast" came to be used in the latter context!

Kind Regards, John

 

[shagster]

Thanks for all the replies (and the interesting discussion). I've decided it's pointless to think about upgrading these light fittings until one of them fails (either tube or ballast).

 

[JohnW2]

Thanks for all the replies (and the interesting discussion). I've decided it's pointless to think about upgrading these light fittings until one of them fails (either tube or ballast).

That may well be the most sensible approach.

Kind Regards, John