LED Work lights for milling machine

[John Stevenson 1Participant @johnstevenson1]

Here's one answer

Build two CREE lights into the end of the spindle casting, in this case the spindle is a HF converted motor.

Switch all the lights out, supply with 5v at 350ma

Prepare to start welding

[Michael HornerParticipant @michaelhorner54327]

wow!

[Sub MandrelParticipant @submandrel]

One of my stepsons gave me a Cree torch for Christmas. Scary bright, with variable brightness and flashing. It has a Lithium battery and a scary looking charging arrangement…

Neil

<Hurriedly removes grocer's apostrophe before anyone can notice>

Edited By Stub Mandrel on 18/03/2013 21:06:26

[modeng2000Participant @modeng2000]

I came across this on another site and thought it might make interesting reading with this increased use of LED lighting for our machine tools.

http://lnk.nu/cree.com/2dnu.pdf

Edited By John Stevenson on 03/04/2013 08:57:55

Edited By Diane Carney on 14/04/2013 00:01:40

[John HinkleyParticipant @johnhinkley26699]

Hi,

Can a moderator please edit the long url in modeng2000's post to link – it's not only made the posts go under the ads, but on my iPad they're coming out the other side!

John

[modeng2000Participant @modeng2000]

Sorry about the long url, it is fine on my display so I thought all would be ok.

John

[dcostaParticipant @dcosta]

Good morning John.

You could also do that ***LINK***.

Regards
Dias Costa

[Michael GilliganParticipant @michaelgilligan61133]

Excellent, and very "resposnible" info from Cree.

… Essential reading for anyone using LED lights.

Thanks for posting the link.

MichaelG.

[Michael GilliganParticipant @michaelgilligan61133]

Erratum

for "resposnible" please read "responsible"

… but please do read the Cree document.

MichaelG.

[Sub MandrelParticipant @submandrel]

regardless of

LED color, Cree advises users

to not look directly at any

operating LED component

Err… as most LEDs are either indicators or in display screens, does that mean we have to treat them like the Hydra and only watch them in a mirror?

""Didn't you see the car in front brake at the red light, sir?"

"Sorry officer, Cree told me I must not look directly at any operating LED component!"

Neil

[Michael GilliganParticipant @michaelgilligan61133]

Neil,

I think you will find that Cree's definition of an "LED component" differs from your interpretation.

MichaelG.

.

Some further reading, here

Edited By Michael Gilligan on 03/04/2013 11:20:56

Edited By Michael Gilligan on 03/04/2013 11:21:34

[Sub MandrelParticipant @submandrel]

Mods – apologies but by cutting and pasting from that PDF my text seems to have overstepped the bounds of its box! I should have used the paste as plain text buitton

I understand Cree's document means. I just think a document that specifically states some products are harmless, prints a risk table identifying the ones that are harmless (and which are potentially risky) and then says don't look at any of them is taking the precautionary prinicple a bit too far. I see the dead hand of the insurance underwriter inserting that sentence into an otherwise very good document.

I see that Wikipedia is behind the curve and still refers to the laser regulations.

Neil

Edited By Stub Mandrel on 03/04/2013 13:17:49

[Michael GilliganParticipant @michaelgilligan61133]

Neil,

Regarding the Cree document

I think the problem actually lies with the sentence immediately preceding the one that you quoted. [delete the word "of" and the sentence makes more sense]

MichaelG.

Edited By Michael Gilligan on 03/04/2013 13:59:16

[Jim NolanParticipant @jimnolan76764]

I was in Lidle today and they are selling 30 led rope lights that are on an adhesive backing strip and can be shortened. Might work in some applications?

Jim

[John Stevenson 1Participant @johnstevenson1]

Bought a couple of the panels as shown in the first post.

Stuck them inside a die cast box and wired them in series with a bridge rectifier so they will run off the machines 24v AC lighting circuit, I get 28v DC

Then mounted these on one of the lock line coolant pipes which works but isn't that great due to size and weight but hey, it's working.

Yesterday doing some deep keyways with the light close up on the vise I noticed that it has a definite strobe effect. Not enough so you will stick your finger in but visible enough so that by playing with the speed control you can get it to change from going forward, slow it, stop it and then make it appear to go in reverse.

No idea if it's the fact I have two side by side on the same supply

[peter walton 1Participant @peterwalton1]

To get rid of the strobe effrct you will need some capacitance smoothing added.

If the amps are quite high then a lot of capacitance will be needed.

Peter

[Ian S CParticipant @iansc]

Or you can calibrate it and use it as a tacho. Ian S C

[Sub MandrelParticipant @submandrel]

+1 to Peter's suggestion.

Neil

[Ian PParticipant @ianp]

Posted by John Stevenson on 16/04/2013 09:06:16:

Bought a couple of the panels as shown in the first post.

Stuck them inside a die cast box and wired them in series with a bridge rectifier so they will run off the machines 24v AC lighting circuit, I get 28v DC

Then mounted these on one of the lock line coolant pipes which works but isn't that great due to size and weight but hey, it's working.

Yesterday doing some deep keyways with the light close up on the vise I noticed that it has a definite strobe effect. Not enough so you will stick your finger in but visible enough so that by playing with the speed control you can get it to change from going forward, slow it, stop it and then make it appear to go in reverse.

 

No idea if it's the fact I have two side by side on the same supply

John

24V AC after going through a bridge rectifer is not DC, (well not pure DC). The effect you are seeing is because the LEDs are not continuously lit. They may look like they are on all the time but in fact because LED have very fast response times (no filament to heat up) they will definitely be dark for a very brief period every cycle of the supply.

Adding capacitance will get over that problem but it also raises the voltage and you might overun the LEDs.

I have not seen the LED panels you are using but I assume they will consist of a series/parallel array of LEDs and resistors intended to be used on 12V DC systems, If they are designed for automotive applications they should cope with spikes and surges and 12 Volts that is actually over 14V (when the engine is running.

It would not surprise me if you could compare two your panels side by side, one driven on pure DC and one on your 'half of 24V' system, that the DC driven one produced a better quality (colour) of light.

Driving LEDs properly is actually quite a complex subject (not one I know much about) but they do perform well enough for most purposes with the most rudimetary supplies.

Ian P

 

PS What are you using to measure the 28 Volts? If your meter is good quality digital then it will be reading the true RMS, If you add a capacitor the voltage will increase significantly, try it.

 

Edited By Ian Phillips on 16/04/2013 22:18:05

[John Stevenson 1Participant @johnstevenson1]

It was a crappy old £400 fluke meter, couldn't find my decent Aldi £3 one.

[BazyleParticipant @bazyle]

My own test on some panels showed they didn't turn on with a 6v lead acid battery so with your unsmoothed supply it will be off for a significant period at the start and end of the cycle.

I also got 12LED panels which takes 80ma on 12v. Thinking of using some along the underside of shelf over bench and for illuminating small areas like dials.

Some of my panels are wired the wrong way round ie red negative, so don't be put off if they don't seem to work at first.

Final note – I got a new broadband router last week and the flashing blue LED on that lights up the front room all on its own.

[John Stevenson 1Participant @johnstevenson1]

By my calculations if I fit a cap I'll be runing at 35 volts which should be Ok at 17.5 v per panel.

I have run one of these at 15v for a whole day with no problem and have pushed one up to 22v for a short while to see it it could take it, bout a few so if I blew one, no sweat.

I'll stick a cap on tomorrow and try it, need to modify it anyway as the lock line stand isn't up to it but I have some ideas on this anyway.

[Les Jones 1Participant @lesjones1]

Hi John.
I would suggest using about a 100uF 50 V capacitor. Also put a resistor in series with the panels to drop the voltage to 15 v per panel. If your 24 V AC IS 24 V then I recon you will have a little less than 35 volts. (24 x 1.414 = 33.9 less about 1.4 volts drop in the bridge rectifier = 32.5) But as the transformer will be very lightly loaded you will probable have a slightly higer voltage. I have bought 2 differnent types of these panels The first version uses type 5050 LEDs (These have 6 pins on each LED package) They consume 360 mA on 12 volts or 620 mA on 15 volts The second type uses type 3528 LEDs (These have 2 pins on each LED package) They consume 230 mA on 12 volts and 430 mA on 15 volts. Assuming your supply is 35 voltsthen if you have the panels with 5050 LEDs the
the resistor required will be 5/0.62 = 8.06 ohms (Use 8.2 ohm) use a 5 W (or larger) resistor if the panels use the 3528 LEDs the the resistor reqired will be 5/0.43 = 11.63 ohms (Use a 12 ohm) use a 3 W (or larger) resistor

Les.

[John Stevenson 1Participant @johnstevenson1]

Thanks to Les we got somewhere, most of the assorted caps were only 25v working and thought this was a bit close. Found a 47uf 50 and tried that but still got the strobe effect.

Searched a bit harder and found some 1000uf at 100 v working and this cured it.

Then decided to do something about the lock line mounting which just flooed with the weight of the head.

As it stood or rather not quite stood tonight, need to make an acrylic cover on the laser for this.

So, and this is a tip I pinched from a guy called Evan Williams off another forum. He used black binding wire but when you work for rewind companies copper wire is easier to get hold of.

9 winds round my elbow like winding cable.

Twist it up on two bars.

then cut the ends off and thread thru some flexible consuit with the correct ends just for looks.

Jobs a good un and this was taken tonight with no other lighting on at all.

[Les Jones 1Participant @lesjones1]

Hi,
Here are two other LED light sources that others might find useful.

10 Watt LED floodlight.

These are available on ebay for about £11.00
They are claimed to be IP65 rated and are available in 12 V and 230 v versions.
The 12 V version does not work very well on 12 V DC but is OK on 12 VAC as this gives about 15 V when rectified inside the lamp. (They need about 15 V DC to work well.)
They are dicast so they are quite heavy (350 gm) so they would need a good flexible mount if used as a machine light.

10 Watt LED array.

These 10 Watt LED arrays are VERY bright but they must be mounted on some kind of heat sink to keep them cool. The array is about 22mm x 30mm. There are two types. one is an array of three groups of three series connected LEDs connected in parallel. These reqire a voltage of about 9 to 10 volts. Like all LEDs they MUST NOT BE DRIVEN from a constant voltage source. They should be driven from a constant current source (900 – 1000 mA for this type. ) which can be as simple as a contant voltage supply a few volts above the LED voltage with a suitable series resistor. THe picture shows one of these arrays mounted on the lid of a 3.5" disk drive for cooling. The components above the disk lid are a proper constant current source. The second type of these LED arrays is made from nine LEDs connected in series. These require a CONSTANT CURRENT of about 330 mA. The voltage across this array will be about 20 – 30 volts.
I have bought 5 of each type for about £7.50 (About £1.50 each.) to try out. (The second type has not yet arrived.)

Les.

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