Announcement

Collapse
No announcement yet.

The circle LED mill spindle light -- update

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • The circle LED mill spindle light -- update

    Problems did crop up with the 'umbrella' circle LED light and though it involved the power going to it - I'm not not up enough on 'lectrics to say just what!

    Heres what transpired -- had that 9v wart on it, and the first time I was actually using the mill for a good while leaving the light on, I noticed (after an undetermined time -- 30min/hour? that it was out. On checking it over determined the wall wart was dead and the lite was OK, so tried another wall wart of 5v/10a and after about 5 min the light would start to do do a slow blink -- could not find a resistor in my junk that would change any thing enough, So, based on one of the previous posters suggestion (crrmeyer/Charles) I went to Radio Shack and got a 4 1/2v/1600ma wall wart.
    http://www.radioshack.com/product/in...ductId=2049707
    Hooked it up this morning and its been on now some 12-14 hours with nice bright lite, no blinking and no discernable heat off the bulbs, so it would seem this is gonna work.

    So you guys that ordered one of the lights ....well, be prepared.

    Another glitch arose with using hot glue to stick it -- that didnt work either -- that chinese metal was just toooo slick The obvious answer to that is, of course, huh Frank Ford?, to use 2-3 little button magnets.
    If everything seems to be going well, you have obviously overlooked something........

  • #2
    I've got a 5V Wall Wart set aside of this project. What would it take to make it work correctly?
    Russ
    Master Floor Sweeper

    Comment


    • #3
      Limit the current to the amount the light normally draws from batteries. The wart also must be able to supply that amount of current comfortably so it will need to be about a 800 ma or better rating based on the reported current in the previous thread. One easy trick to use is to drop the voltage with a diode. Any 1n4000 series diode will work. Radio Shack has them in packs of 20 or so for a couple of bucks. Each diode in series with the supply will drop the voltage by about 1/2 volt. Since the LEDs are all in parallel dropping the voltage has the effect of limiting the current. White LEDs need about 4 volts DC minimum to work properly.
      Free software for calculating bolt circles and similar: Click Here

      Comment


      • #4
        I spotted an LED ring-light at the local Shucks auto supply (also known as Checker and a few others, in other places) and gave it a look. This particular one, unfortunately, was too small an ID to go around my Bridgeport-clone spindle, but probably would have been fine for my smaller mill-drill spindle.

        Just throwing that out as a possible alternate source, if anyone needs one.

        The best light I ever saw was (as was mentioned in an earlier thread) one of those ring fluorescent bulbs. The fellow I saw using it had it on one of those Grizzly mills with the ram-mounted head (Millrite clone) and was doing woodworking with it (as Griz advertises the mill for.)

        So he didn't have any real swarf protection for the bulb, and all he did was paint the top half black.

        I'm sure somebody could fab up an aluminum-and-plexiglass housing for one for a metalworking application, but on the other hand, it'll start getting even bulkier that way.

        Doc.
        Doc's Machine. (Probably not what you expect.)

        Comment


        • #5
          One problem I can see with this setup is that often when I'm keywaying shafts unless I use very long cutters I finish up with the extended quill or head bumping a fan or similar on the job.

          Anything this size mounted on the head or quill would limit what I need to do as not everything is flat and stands proud.

          .
          .

          Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.



          Comment


          • #6
            I got mine mounted yesterday. I used the magnets. I'm using a small plastic battery holder similar to what radio shack sells on mine. The advertisement says it will run 30 hours on 3 AA batteries, that's good enough for me.


            BTW- I made a AA holder for my chi-com digital calipers on my mill and haven't changed a battery in about a year even with our cold winters.
            - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
            Thank you to our families of soldiers, many of whom have given so much more then the rest of us for the Freedom we enjoy.

            It is true, there is nothing free about freedom, don't be so quick to give it away.

            Comment


            • #7
              The claim for 30 hours on a set of batteries, will doubtless be based on "till it's too dim to see". LEDs pull progrssively less current as the battery voltage drops. What is quite bright at first will often fall off to a mediocre glow in 1/2 of an hour when pulling at 800ma from a AA battery pack. At the end of the hour the current will drop to more like 150 ma or so. This is what lets them make such long life claims.

              As a certified flashaholic (flashlight freak) I've worked with a lot of LEDs on my machines. I have a small LED light on my micro mill and another one on my lathe. Both are driven by leftover wall warts.

              I can help with formulas if needed.

              Dan
              At the end of the project, there is a profound difference between spare parts and extra parts.

              Comment


              • #8
                One way to build an ultra slim light would be to use surface mounted LEDs on a circular PCB and then drop that into a wide face groove on the back of a 1/8" - 3/16" thick polycarbonate ring. The back could be sealed with whatever will withstand oil and coolant.

                The surface mounted LEDs will lack the lensing of the T5 LEDs but will cover a large area with diffuse light with the lack of aiming made up by the quantity of LEDs.

                Incidentally, for sharpest image, a fluorescent ring or LED ring are not the best solution. Separate light sources from several directions create the "interference" necessary to give the eye and brain a sharper image.

                But back to the super thin ring, maybe a group project (buy) is called for if there is interest

                Den

                Comment


                • #9
                  I am working (have been for a while) on a lathe work lamp that uses 3 1 watt medium white emitters that cost about 2 dollars each from DealX. It can easily be adapted to work on a mill as it is a triangular configuration with a hole in the middle. The actual light assembly is 1/4 thick with small shields that project another 1/4 on each LED. I'll post a picture later or tomorrow.

                  There are some cheap and effective solutions to the power issue too using regulated micro power supplies that cost a few dollars. More later.
                  Free software for calculating bolt circles and similar: Click Here

                  Comment


                  • #10
                    As a cheap & safe power source for lighting LED's would it not be possible to power them somehow by winding the lead around the power cable for the machine? I recall you could power an LED by wrapping wire around a soldering iron.
                    Peter - novice home machinist, modern motorcycle enthusiast.

                    Denford Viceroy 280 Synchro (11 x 24)
                    Herbert 0V adapted to R8 by 'Sir John'.
                    Monarch 10EE 1942

                    Comment


                    • #11
                      Nice thought but a little too simplistic. Wrapping a wire around the outside of the cable won't pick up any power. To do that you need to wrap a wire around a small chunk of iron and also wrap just one of the current carrying conductor around that piece of iron too. That does work and is called a transformer. You are possibly thinking of lighting up a mini neon bulb using stray electric fields near a current carrying conductor. The amount of power available that way is thousands of times less than what is needed.
                      Free software for calculating bolt circles and similar: Click Here

                      Comment


                      • #12
                        So, I freely admit to being out of my depth here. I do have the background (though not used in MANY years to eventually research and figure out the answer, but it's beyond the point of diminishing returns for me, so I'm hoping someone with fresh and available knowledge can provide a leg up, so to speak.

                        So if I substitute a 4.5V xformer, will that be sufficient? Or is there still too little resistance in the circuit and damage would result. Seems like a 5V circuit limited to drop the voltage would be a better choice. The xformer I have on hand is easily able to handle the amperage, and the voltage could be tweaked any number of ways. Being a static "load", it could be a simple resistor easily calculated, or a varistor for "dimming" and fine control, or perhaps a control diode as Evan describes. Any problem with this?

                        And I've run into situations like John describes. And for that reason, I was already planning to do a "twist lock" mount for easy removal. You know, holes for screw heads with slots (arcs in this case) like used to mount power strips and such. I thought about magnets, but I do too much steel and have enough problems with swarf intrusion and such as it is, I'm not adding any magnets even shrouded by the main light fixture. If I need to remove the ring, I still have the 300W articulated arm light I'm using now. It's just that the harsh Shadow and heat of that thing causes it's own problems for general every day use, particularly when I have low precision work just cutting to a layout line or prick punch.

                        Speaking of the fixture itself, I'm pondering whether to use the plastic back, or make an aluminum replacement. But I'm too lazy to drill all those precise holes, so I'll probably use the plastic front as long as it seems to hold up.
                        Russ
                        Master Floor Sweeper

                        Comment


                        • #13
                          I can't give you an exact answer. The method of wiring all the LEDs in parallel to run them from batteries is a NOT recommended way of powering LEDs. It is commonly used on cheap battery powered LED lamps and flashlights where saving a penny or two is the difference between profit and loss.

                          The reason I can't give you an answer is that this method of powering an LED or a bunch of them is unpredictable and unreliable. Even with batteries there is the possibility of damage from excess current. Or, they must err on the safe side so much that the LEDs are running at much less than rated current. The problem is that an LED doesn't conduct like a resistor.

                          With a resistor if you up the voltage the current is directly proportional to the increase. With an LED once it is conducting and making light even a very small increase in voltage can result in a very large increase in current. It's like raising the water behind a dam. Nothing flows until it is over the top but then even a slight rise results in ALL the extra water running over.

                          LEDs of the same exact type will vary from batch to batch in exactly what voltage it takes for this to happen.

                          The proper way to run LEDs is with a current limiter for each LED or string of LEDs in series only. The only way to determine a safe value of current for your lamp is to measure how much it draws when hooked to your power source. Then multiply 20 milliamps (0.020 amps) times the number of LEDs to arrive at the maximum safe current. Then reduce that to about 75% to account for variations in the individual LEDs and changes in supply voltage. If the lamps draws that much or less when connected to the wart then you should be OK. If it draws more then try a low value resistor or a diode in series with the power lead. Measure again until you get it below the calculated maximum.
                          Last edited by Evan; 03-01-2009, 10:15 AM.
                          Free software for calculating bolt circles and similar: Click Here

                          Comment


                          • #14
                            What happens tif you over-volt LED's? Do they blow or have reduced lifespan?
                            Peter - novice home machinist, modern motorcycle enthusiast.

                            Denford Viceroy 280 Synchro (11 x 24)
                            Herbert 0V adapted to R8 by 'Sir John'.
                            Monarch 10EE 1942

                            Comment


                            • #15
                              Originally posted by Peter.
                              What happens tif you over-volt LED's? Do they blow or have reduced lifespan?
                              Depending on the degree of overvoltage/overcurrent they may be converted into DEDs (Dark Emitting Diodes) or, in extreme cases, NEDs (Noise Emitting Diodes). The lifespan of a NED is very short, and the NED phase may coincide with a PED (Particle Emitting Diode) mode, followed by a permanent DED condition.
                              Weston Bye - Author, The Mechatronist column, Digital Machinist magazine
                              ~Practitioner of the Electromechanical Arts~

                              Comment

                              Working...
                              X