LED/Halogen Drivers

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LED/Halogen Drivers

This topic has 16 replies, 12 voices, and was last updated 12 October 2022 at 16:11 by Martin Kyte.

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10 October 2022 at 10:05 #616764
Lynne
Participant
@lynne
Good Morning, My mill, and lathe are currently illuminated using MR16 12v halogen driven by a Dais DA-E60 electronic transformer. I would like to replace the halogen bulbs with led's. Can I use the current drivers. Searching the web does'nt really tell me yes or no, but most sites tell me that one needs an LED driver. Would someone enlighten me. Thanks, Lynne
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10 October 2022 at 10:05 #28871
Lynne
Participant
@lynne
10 October 2022 at 10:29 #616768
Neil Wyatt
Moderator
@neilwyatt
That's a good question.

My experience is that 12V halogen bulbs swap well with 12V LED ones.

'Current' driver misled me for a moment as I thought you had a 'constant current' power supply which would overwhelm LEDs at Halogen currents!

Neil
10 October 2022 at 12:02 #616782
John Baguley
Participant
@johnbaguley78655
We used to have 12v Halogen bulbs driven by electronic transformers fitted over the bars at my local RBL Club. I swapped all of the bulbs for LED a few years ago and they work fine with the original electronic transformers. The 'transformers' last a lot longer now as they used to regularly fail with the old halogen bulbs.

John
10 October 2022 at 12:30 #616788
Ian P
Participant
@ianp
It depends on what you mean by LEDs

An LED is a single 'Light Emitting Diode' but has nowadays become the term for all sorts of lighting equipment that incorporates LEDs. This lighting equipment can contain anything from one to hundreds of diode elements and may or not contain the specific circuitry that is needed to correctly drive the LEDs.

If you purchase a light unit containing LEDs and its labelled or marked as being suitable for (say) 12 Volts then it will already incorporate the necessary current limiting components and can be connected in place of a incandescent lamp.

Ian P
10 October 2022 at 13:26 #616790
Andrew Entwistle
Participant
@andrewentwistle
Hi Lynne,

Something to consider when moving from halogen to LED lighting of machine tools is the stroboscopic effect of LEDs driven by most switched mode power supplies. This can make the moving chuck appear slow moving or even stationary. For this reason I have kept the halogen illumination for the lathe at work.

Andrew.
10 October 2022 at 16:14 #616801
Lynne
Participant
@lynne
Hi, the LED bulbs I am proposing to use are like for like replacements for the halogen bulbs, ie mr16 51mm dia. 4.6w upwards, depending on what I am prepared to pay. Seeing as others have done a straight swap without problems, that is what I propose to do. I will watch out for the strobe effect on the lathe. Thanks for the responses. Regards Lynne
10 October 2022 at 17:22 #616811
duncan webster 1
Participant
@duncanwebster1
Posted by Andrew Entwistle on 10/10/2022 13:26:02:

Hi Lynne,

Something to consider when moving from halogen to LED lighting of machine tools is the stroboscopic effect of LEDs driven by most switched mode power supplies. This can make the moving chuck appear slow moving or even stationary. For this reason I have kept the halogen illumination for the lathe at work.

Andrew.

Is this real? Typical switch mode power supply works at 40 kHz, so to make a 4 jaw chuck stand still it would need to be doing 10,000 revs per sec, which is a bit more then most model engineers machine tools.
10 October 2022 at 19:17 #616822
Frances IoM
Participant
@francesiom58905
no cheap LED drivers do show a strobe effect – the cause is the 50Hz or 100Hz if full wave rectifier before the PWM output stage modulates the drive voltage and the eye is quite sensitive to changes of light intensity.

Cure is to stick a relatively large capacitor of correct voltage across the supply

Edited By Frances IoM on 10/10/2022 20:10:52
10 October 2022 at 20:00 #616828
duncan webster 1
Participant
@duncanwebster1
That all makes sense, you learn dome thing every day
10 October 2022 at 22:00 #616837
Martin Kyte
Participant
@martinkyte99762
I have always had a tendency to build my own LED drivers especially for lab work. My issue was always making sure they turned off completely. The solution was to add a parallel resistor to get well below the bias voltage otherwise the current sensing cct would supply sufficient current to cause the led to emit the odd stray photon which really messed up the microscopy. Different situations need different solutions.

regards Martin
11 October 2022 at 20:03 #616966
Ebenezer Good
Participant
@ebenezergood76202
I've got GU4 12v led replacements for halogens in my kitchen lights, they don't seem to last very long, I was thinking about replacing the 3 transformers with an led driver to see if it improved lamp life.
12 October 2022 at 11:13 #617009
John Doe 2
Participant
@johndoe2
By coincidence I have just been changing my bathroom down-lighters for LED units, and have found some really good ones.

They are by Xcite in Worcestershire; order code: XCBDL10WW. I got mine from City Electrical Factors: CEF, and they are available on line. There are two colour temperatures available. 115mm diameter, including the flange, and 82mm in length.

They are completely sealed to IP54 – the LEDs are integral and not plug-in – and are double insulated and self contained: mains in, no external driver required. Plastic housing with a flange on the front. I am sure they could be easily adapted by removing the side clips and mounting to a bracket for machine work.

They give out an astonishing amount of bright light – 700 lumens – and the LEDs are mounted behind a diffuser layer, so are shadow free. A claimed 30,000 hour life with a 3 year warranty.

By spinning my variable speed hand-held battery drill close under one of the lights, I can just make out a weak strobe effect at some speeds, but I don't know if that would be a problem on a large machine tool.

I have no connection to Xcite or CEF.

Edited By John Doe 2 on 12/10/2022 11:31:57
12 October 2022 at 11:47 #617015
martin haysom
Participant
@martinhaysom48469
i use all LED light in my workshop never noticed the "alleged" strobe effect
12 October 2022 at 12:00 #617017
Martin Kyte
Participant
@martinkyte99762
Strobing is a function of the driver cct not the led. The cheaper the driver cct the more light fluctuations you get.

regards Martin
12 October 2022 at 16:08 #617035
SillyOldDuffer
Moderator
@sillyoldduffer
Not all strobing is strobing!

The same effect can be caused by pure unmodulated light bouncing off a shiny surface like a chuck jaw.

In this picture I've angled the stopped chuck so the jaws don't bounce light into the camera:

And in this photo the chuck has been turned slightly to angle the jaws to reflect light into the lens (or eyeball):

When the chuck is rotating the jaws are much brighter at one angle between eye and light source than the others, which is enough to fool the brain that the chuck isn't turning, or might if it wasn't for gear and motor noise.

In my experience real strobe effect caused by rpm matching the frequency of a flashing lamp is quite hard to see unless the rotating item is strongly illuminated by flashes whilst the rest of the workshop is dim. Strobe accidents were certainly a problem on noisy poorly lit old-fashioned factory floors. They tended to be filthy black, with relatively few lamps in the ceiling for general illumination, maybe a work-lamp on the machine and lots of distractions. And the racket caused by surrounding machines made mistakes far more likely because the operator couldn't hear his own machine.

I think strobe effect is unlikely to catch a Model Engineer out in his own workshop partly because we know when our machines are turning and partly because decent lighting makes strobe effect hard to see in a reasonably bright room. Anyone ever had an accident due to strobe or my reflecting effect?

Dave
12 October 2022 at 16:11 #617037
Martin Kyte
Participant
@martinkyte99762
I would agree with that Dave .

regards Martin
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