LED Work lights for milling machine

Hi Michael,

I was assuming the OP had no previous experience of electronics. An off the shelf PWM unit would be fine, but 47R wirewounds are also cheap as chips.

With PWM the cool thing to do is to make the LEDs flash a rude message in morse, but so fast you can't spot the marks and spaces

Neil

Fair comment Neil

MichaelG.

Les,

Thanks for your reply. That's much as I expected. I have a variable power supply that I can use for now while I try to find a suitable source that will send to France.

John

Don't you have an old modem / router / some other electrical gizmo power suppy? Ask around your friends as the world is full of them and mostly 12v. We ship about 2 or 3 million a year.

Hi Bazyle,
You suggestion is a good one but I have come across a few routers that use a 12 V AC supply. John would need to check that they are the type with DC output.
One advantage with the non plug in type is that they could be mounted inside the mill control box and supplied from the mains inside the mill to make a tidy installation.

Les.

Edited By Les Jones 1 on 05/03/2013 10:22:06

I have used an old 12v dc plug pack to power the LED's. Also mounted a power outlet on the outside of the mill column and wired it to the main on/off switch on the mill. Added a double adaptor to supply power to the plug pack and also to the power feed. When the mill is turned on, the power feed and the LED's also come on.

Sent to China to get some low wattage lights, according to the bumf they are very economical to run.

Parcel arrived today, unpacked it and fitted them to my X3.

Not very bright at all, might be economical to run but I feel someone is taking the pìss ??

Inspired by John's picture I just went out to take a photo of my mill lit up with a hurricane lamp, but my blooming camera's gone flat.

Neil

Edited By Stub Mandrel on 05/03/2013 20:11:04

Hi John,

Not sure which lights you purchased but mine are definitely bright enough to iluminate the work area. In fact I have removed the globes from the existing lamps (shown it top right of photo) because it was too bright. (Photo was taken in a dark room with only the LED lights turned on)

Paul.

Edited By Paul Lousick on 05/03/2013 21:40:34

HI John, Had a closer look at your photo and think that I know what the problem is. You have the lights pointing up towards the ceiling and they are not shining onto your work. Gives a nice mood atmospere to the workshop though. A couple of tee light candles would probably have the same effect. Nice one !

hi john

looks to me like you bought the wrong ones they look like t-lights to me

have a look at the start of this thread sombodys put a link on

i got 6 and i have'nt wired them up yet but i have got my sunglasses out ready

The type to get are the ones shown in the very first post which have 48 led's surface mounted on an area of about 5 by 4 cm. With a 12V led driver they are BRIGHT, I was going to fit two on my mill but might only need one.

Doug

Seriously, I did buy some of these panel ones from China, just not got round to looking at them until last night.

I did post earlier I had sent for some. Don't know if they are the same as every one else's, come with three adaptors to replace bulb fittings ?

First of all tried it on a wall wart at 6 volts but no light which suprised me as these things are usually voltage sensitive if they don't have an inbuilt driver. So last night stuck it on a professional power supply.

Up to 7.5 volts they don't work, after 8 v then come on but not that bright, at 12v they are quite bright and throw off a decent light, power supply was reading 0.45 amps. 15v increased the light a fair amount and flat out at 22 volts it was drawing 1 amp but very, very bright.

No idea on the life at this voltage or heat given off but today I'm going to soak one at 15 volts and se how it last up.

Very impressed on what light they do throw out.

Depending on the type of LED array, you might need to be carful that the supply is smoothed DC rather than half wave rectified - simple rectified supply would produce a strobe at 50 Hz I would imagine.

John,

Please see my earlier post, in this thread, regarding PWM dimmers.

... It's the way to go !!

MichaelG.

What a brave chap you are John, 22V at 1A sounds a bit extreme for these panels but it does show they are very tolerant of over voltage. Can't imagine they would last long at that voltage but it will be interesting to see how you get on at 15V for soak test.

Doug

Hi John,
The reason for the LEDs not comming on until the voltage exceeds about 8 volts is that LEDs behave a bit like a zenner diode. They do not start to conduct until the voltage across them exceeds a certain value. This is about 3 volts for white LEDs and about 1.8 for red LEDs As you LED arrays will have groups of 3 LEDs in series they are just starting to conduct with about 2.7 volts across each one. As Neil pointed out earlier on this thread you can consider the array as 3 LEDs in series with an 8 ohm resistor (In the type of array I bought) at 12 volts the voltage across the 3 LEDs was 9.3 volts and 2.7 across the resistor which gives acurrent of 2.7/8 = 338 mA As the voltage across the LEDs stays more or less constant with a 15 V supply there would be 5.7 volts across the resistor giving a current of 5.7/8 = 713 mA.

The arrays I bought used type 5050 LEDs which is actualy a package containing 3 individual LEDs. Looking at the data sheet on this device I could not decide if the disipation rating refered to the package or each individual LED so I do not know the maximum current it would be safe to pass through each LED.

For another project I bought some of these 12 LED arrays

Here is some information on this type.
The array consumes about 110 mA with 12 volt supply.

The 5050 LED package contains 3 LED's

The LED's are arranged as follows.

The three LED's in each package are connected in parallel.

They are arranged as 4 groups of three LED packages. The 4 groups are in parallel. There is asingle 10 ohm current limiting resistor in the negative lead. There is a bridge rectifier (4 seperate diodes) so they can run on AC or DC

110/4 = 27.5 mA So each package of three LED's passes 27.5 mA Each LED within the package passes 9.2 mA

12V - 1.2V (For drop in bridge rectifier) = 10.8 V
Drop across 10 ohm resistor = 10 * 0.11 = 1.1 V
10.8 V - 1.1 V = 9.7 V
As this is across 3 LED's in series each LED has 3.23 volts acress it.

Les.

Has anyone tried the long strips of 48 leds that also come up on ebay? I might get some next week. I'm wondering if they would wrap round the rim of a normal machine lampshade and give a more spread light than the blocks. Mounting is not quite so simple.

Reliability - although they quote very long life probably based on the best case figure given by the LED silicon mfr they are expected to be used in car interior lights which are only on for a minute at a time. Probably only do an hour a month so they might not be so good when used for a few houts at a time.

I'm not brave, I was born with a crowbar in one hand !!

Point is somewhere down the line someone will over rate one, nice to know what they will stand.

Anyway, been running all morning at 15v sat , not glued to a piece of alloy 4" square by 1/4" thick, alloy is hardly warm.

If you rest the side of your hand on the LEDS they are warm but comfortable warm,

not "shìtthatwasf@##kinghot" [tm] warm

Hi Bazyle,
On some other forum I saw someone using a ring of LEDs on their mill like these.
They are sold for use on cars. they seem to be called "angel eyes" If you do a search on ebay for "led angel eyes" you will find them in different sizes.

Les.