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Thread: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.

  1. #91
    Flashaholic JP Labs's Avatar
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    Default Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.

    Just a quick update so you guys know I am still around! I am very busy at the moment, with travel, work, collecting firewood for the winter, car maintenance, and other chores.

    My lamp, ignitor, housing, and power supply are sitting here in boxes, ready to play as soon as I can free up some time and clear up some bench space. I hope to unpack it this weekend.
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    Default Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.

    I am waiting.

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    Flashaholic JP Labs's Avatar
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    Default Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.

    OK, today I finally made time to clean up shop space and unpack my toys.

    The Power Supply was very well packed:


    So were the housing and ignitor:


    But, do they work? A bit worried about the gamble.....

    Power supply lights up, and amps preset works. Good!


    The housing was designed for a lamp that runs anode (+) up. My HBO200 runs anode down. So I had to install upside down for the housing, placing the arc way too low, even at full adjustment. This could be remedied with a spacer, but it's good enough for testing.


    Crossing my fingers.......












    Will I be disappointed?




























    Hooray!!


    It was fully warmed up within about 8-10 minutes. I ran it for about 15 minutes.


    The hot spot completely misses the optics, so the fiber cable is dim.


    Next I need to start working on a lamp mount for the searchlight. Progress will be slower than before, it is a very busy time. But I hope to work on it every weekend for a while, at least.
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    Default Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.

    Hurray! The power supply issue is out of the way now.
    WWII 60" Carbon Arc (Sold), 1.6KW NightSun, 1KW VSS-3A, .8KW TrakkaBeam, 600W M-134 Light, 500W X-500-14s, 500W Starburst, 500W A120b, 450 Watt AEG German Leopard 1 Tank Light, 300W Locators, Megaray, 150W Communicator, Maxabeam Gen3, Pichel 75W Mini-Novas

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    Default Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.

    Nothing new?
    WWII 60" Carbon Arc (Sold), 1.6KW NightSun, 1KW VSS-3A, .8KW TrakkaBeam, 600W M-134 Light, 500W X-500-14s, 500W Starburst, 500W A120b, 450 Watt AEG German Leopard 1 Tank Light, 300W Locators, Megaray, 150W Communicator, Maxabeam Gen3, Pichel 75W Mini-Novas

  6. #96
    Flashaholic JP Labs's Avatar
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    Default Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.

    Ok, I'm back. Like I mentioned, it's been busy.

    I did finally get back to playing with the light a little bit today. But first, a totally off topic diversion for a moment. This is what has used up my free time the last couple of weekends:



    A wood shed and a mechanical wood splitter. The latter is a spring loaded, gravity assisted gizmo which spares me the effort of swinging a splitting maul.
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    Flashaholic JP Labs's Avatar
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    Default Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.

    Here are a couple more shots of it running:




    The lamp is still positioned about 1/4 inch too low here, so it's a small fraction of the intended intensity.

    All of the cables plugged right in. All of the various safety interlocks worked. I had to reverse the DC+ and DC- at the housing, though. The HBO lamp has + (Anode) on the bottom; it came with the Cathode connection on the bottom.



    I also collected several bits which will be helpful in mounting the lamp, although in what configuration, I am not yet sure.



    Included are a 10 mm brad point drill and a 10 mm center cutting end mill, to make the pocked for the lamp base. Also a pair of 4 mm x 0.7 mm plug taps, so I can retain lamp in my pending custom heatsink, using the threaded terminal at the very end of the lamp.
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    Flashaholic JP Labs's Avatar
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    Default Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.

    The Delrin and PVC pieces shown above will be used for electrical isolation. The heat sink will be machined down to fit inside a cylindrical plastic housing which attaches to the reflector. So, only the cool, outer edges of the fins will touch plastic.

    I need to devise the means of lamp positioning before I go much further.

    Here is a shot on the inside of the lamp housing. Note the mechanism at the left. This positions the reflector in x,y,z axis. I would like to convert this for lamp mounting use, but it will be very difficult to keep the forced air cooling if I do. The body has no passages for airflow, and it fills the ID of the reflector fairly tightly.



    Isn't it pretty in there?

    Here is the outside view:



    And here it is, removed - it is the round piece to the right. The black one is the shutter assembly and a 'dark shield' interlock:



    The entire inner assembly, the gray and the silver parts, move in and out about 0.240". The silver part angles up/down, left/right PLENTY far. I would like more z and less x,y, but the mechanism is almost perfect for the job. Except for the lack of an airflow path.

    I could simply make the lamp adapter long, like 4" instead of 2", and feed the cooling air in from the side instead of axially, but I really don't want much excess length hanging off the back of the reflector. Worse, I think, is this solution would require the lamp to be cantilevered a long ways out from the adjusting mechanism. That would not be good for precision.

    I could also do a simple 3-screw mounting with springs under the screws. But, then, all 3 screws need to be turned for any adjustment. I want one just for focus, and two independent ones for the x,y.

    Next, I need to make the heat sink, play with the pieces for a while, and think.
    Last edited by JP Labs; 11-01-2014 at 10:04 PM.
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    Default Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.

    I figured out the necessary dimensions to mount the lamp and center the arc at the reflector's focal point.

    The arc location is 1.575" (40 mm) from the face of the lamp's Anode end. The parabola has an externally threaded mounting sleeve that was not shown in the original drawing, but is sketched in, below.

    This drawing is marked up to reference the arc location to the rear flange of that mounting sleeve.



    A 2" schedule 40 PVC pipe is a slight interference fit with the smooth ID of that threaded sleeve. So, I can use the PVC as the first layer of HV isolation, between the lamp adjuster and the reflector/frame assembly. This will enable gross tuning of lamp center, to enable a range of lamp sizes to be fitted.

    I think, with a little creativity, I will be able to use the x,y,z mirror stage from the lamp housing as my lamp adjuster.



    Here it is disassembled, below. The part on the left is the part that moves in and out, z axis. The tilting stage (x,y) is on the bottom of that, barely visible through the hole and under the bottom edge.

    The part on the right is the rear cap, upside-down in this view:




    Here is the x,y stage removed from the end of the z axis piece:


    Remember that the positioning stage had no airpath. Well, it does now. Almost. I turned down part of the OD to allow annular airflow. Then I cut a path in the front face to spread air out in the gap between the z axis part, and the x,y part:



    Finally, I hogged out a few gaps between key features I can't ruin, from the outer lip around the front face. The result is an air path to feed cooling flow from a fan mounted to the side of the mounting tube, to the back of the x,y stage.

    Below is a VERY rough approximation of how the parts will interface. Note that the main mounting tube, a piece of 2" PVC, is NOT shown here. It will be attached to the flange of the 'top hat' in this picture, and will cover the whole assembly, except for about 0.5" of the heatsink. There will be clearance inside that tube for the guts to move.

    A small blower will be located on the side closest to the camera, mounted to a hole in the (not shown) outer PVC mounting tube. The PVC shown here represents the 2nd layer of HV isolation, to which the heat sink and lamp assembly will be mounted. I might use Delrin or Nylon instead, but you get the idea.

    The heat sink will wind up only about 2" long and will be partly nested inside the insulation piece:



    I still need to drill holes in the x,y stage to feed air to the back of the heat sink.

    Here is the 12v blower I found. It is 3" across by about 1" thick, quiet, and powerful enough for this task, I think:



    Next, I need to figure out how, exactly, I am going to mount the whole thing to the reflector such that there is room for the adjustment range, and airflow. Then, machine a suitable heat sink from that giant donor, above, and start putting it all together.
    Last edited by JP Labs; 11-02-2014 at 06:51 PM.
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    Default Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.

    Just keep in mind that the pvc may gasoff and cause deposit issues at those temperatures.
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    Default Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.

    I think it will be pretty cool there, as they will only touch the outer, coldest part of the heat sink fins. The PVC will be directly fan cooled, too. But thanks for the suggestion; I will watch the temperature and keep an eye on the reflector and glass for any fogging.
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    Default Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.

    Congratulations on your venture. The beam this will throw will be incredible.

    Keep in mind, only certain short-arc lamps benefit from heat sinks. Lamps with Molybdenum "foil" seals don't benefit from heat sinks. Only lamps having seals with rod construction benefit from heat sinks because only the rods are thick enough to transfer the heat.

    Lamps with rod seals are much longer because they have graduated construction to compensate for the expansion differences between the quartz and the electrode shafts, whereas Molybdenum foil in smaller lamps is close enough in thermal expansion to quartz to be usable up to a certain foil size. Only the higher powered multi-kilowatt lamps have the rod construction, because it's a more involved construction and the more simple foil seal construction can't be used because foils have a maximum electrical current due to the limited foil size required for maintaining a seal before the difference in thermal expansion becomes an issue.

    But the foils are not thick enough to conduct practically any heat away from the seal to the heat sink. I had to change my plan after I found this out the hard way. Foil seals need direct air flow to cool the seal. In my testing, even very large blocks of copper heat sinks did absolutely nothing to assist in cooling the seals. Unfortunately you'll likely have this issue too, as the lamp you're using has foil seals. To be fully assured of lamp seal cooling effectiveness in the enclosure, you'll need to obtain from the lamp manufacturer a modified lamp having thermocouples embedded into the seals.
    Last edited by get-lit; 11-03-2014 at 02:59 AM.
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    Default Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.

    Quote Originally Posted by get-lit View Post
    Congratulations on your venture. The beam this will throw will be incredible.

    Keep in mind, only certain short-arc lamps benefit from heat sinks. Lamps with Molybdenum "foil" seals don't benefit from heat sinks. Only lamps having seals with rod construction benefit from heat sinks because only the rods are thick enough to transfer the heat.

    Lamps with rod seals are much longer because they have graduated construction to compensate for the expansion differences between the quartz and the electrode shafts, whereas Molybdenum foil in smaller lamps is close enough in thermal expansion to quartz to be usable up to a certain foil size. Only the higher powered multi-kilowatt lamps have the rod construction, because it's a more involved construction and the more simple foil seal construction can't be used because foils have a maximum electrical current due to the limited foil size required for maintaining a seal before the difference in thermal expansion becomes an issue.

    But the foils are not thick enough to conduct practically any heat away from the seal to the heat sink. I had to change my plan after I found this out the hard way. Foil seals need direct air flow to cool the seal. In my testing, even very large blocks of copper heat sinks did absolutely nothing to assist in cooling the seals. Unfortunately you'll likely have this issue too, as the lamp you're using has foil seals. To be fully assured of lamp seal cooling effectiveness in the enclosure, you'll need to obtain from the lamp manufacturer a modified lamp having thermocouples embedded into the seals.
    Hello, get-lit. Thanks for dropping by and offering your kind, helpful input! I really enjoy your writing, your fascinating beamshot simulations, and the Nightsword design discussions. You have a well honed, BEAUTIFUL design, there. Impressive design/engineering skills!

    That is some new info to me, about the thermal path effectiveness of Mb foil seals, vs rods. It makes sense, but I was not aware of the distinction, and frankly didn't even know about the difference in these alternative designs.

    So, if I understand correctly, in the case of a high pressure Hg lamp, with Molybdnum foil seals, which requires forced cooling: the cooling requirement is to keep the foil seals from melting or being overstressed due to differential thermal expansion vs the quartz. You don't want to overcool the quartz envelope itself, however, as that would lower the operating mercury pressure, hurting efficiency and possibly resulting in Hg condensation on the quartz during operation. So, you have to direct air at the two straight sections on either end of the lamp, rather than at the metal caps on the ends, because the thermal path to the metal caps is poor.

    Correct so far?

    So, my configuration will not work for Mb foil seal lamps that require forced cooling. I would need a different, more complex airflow arrangement to actually cool the quartz shafts of the lamp without cooling the spherical envelope.

    In the case of a rod-style lamp that requires forced cooling, the rods carry heat to the end caps more effectively, allowing the caps, or a heat sink in thermal communication with the caps, to be the forced-air target, and still keep the Mb rods cool enough. In this case, the rods would help cool the electrodes themselves, too. I could run such lamps in this configuration, assuming the cooling rate is correct for each lamp end.

    Still good?

    The Osram HBO 200 W/2 lamp I am using now is a Mb seal type lamp, as you observed. Remember, it is a very high pressure Hg lamp, not an Xe lamp. From the spec sheets I have seen, it says 'passive' in the column for cooling requirements. The larger lamps (HBO1000 for example) will state an air velocity requirement in this same data field. So, I think this lamp does not require forced air cooling.

    Would you agree that I am interpreting this specification correctly?

    There is also a maximum temperature listed for the HBO200 lamp base ends, in this case 250C. So, I could actually run this lamp with no cooling, as long as the base stays below 250C. Because it is undesirable to overcool the envelope of a VHP type Hg lamp, the less cooling, the better, to a point. The lamp needs to reach design temperatures to work well, mostly due to the need to achieve high Hg gas pressures.

    My reason for using forced air cooling with the HBO200 is not to cool the lamp itself, but to enable me to use relatively low temperature plastic as my HV isolation material. If I simply installed the lamp directly into a plastic base, I would achieve the necessary HV isolation, but the plastic would be insulating the lamp base end, and elevating it's temperature. And the plastic would soften, expand, and perhaps melt. So, I am using a heat sink to make my lamp mount. The cooling air only needs to reduce the temperature of the heat sink enough so that is can interface to plastic without softening it. The plastic will be further cooled by the airflow. The airflow path will be such that there is no direct impingement upon the round lamp envelope. So, I don't think I need to change the configuration for this HBO200 lamp, I think I am ok. Other reasons for my adding (filtered) forced air are to minimize ozone accumulation inside the light, to keep overall temperatures of the lamp low, and to discourage bugs, dust, or rain from coming inside.

    Does my approach make sense in this context, and do you think it will work for this lamp, considering the lamp's passive cooling rating?

    Note that the Oriel housing I have is rated for this lamp. It simply uses a chunk of brass as the mount at the lower end of the lamp. A fan provides some airflow to purge the housing of hot air, with no airflow directed at any part of the lamp, and minimal flow at the brass base. There are metal light baffles between the fan and lamp which cause a diffuse, low velocity airflow through the housing, mostly near the walls. See pic a few posts up.
    Last edited by JP Labs; 11-03-2014 at 08:57 AM.
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    Default Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.

    FRITZHID, in consideration of your comment about outgassing from hot PVC, I took a better look at the fit of the parts, and what I might do to further increase air velocity over the PVC. I went back to the lathe and reduced the OD of the x,y plate further (about 0.090"). This will increase the bypass airflow around the outside of the heat sink holder, which will pass more air between the OD of the PVC heat sink holder, and the ID of the PVC mounting tube. Now, I am actively cooling the full length of 3 of the 4 cylindrical PVC surfaces, instead of just the inside of the piece holding the heat sink.



    I also carved up the x,y plate to add airflow passages to feed the heat sink:


    This shot shows the PVC heat sink holder mounted to the x,y plate. It is tapered to allow for tilt of the assembly inside the main mounting tube. The heat sink will be similarly tapered. Alignment is not perfect; this was 2AM and things were getting blurry, but I was on a roll. I will need to true it up on the lathe again, to make the heat sink concentric with and parallel to the x,y base:



    In this view, you can see a semi-circular cutout in the left side, near the bottom of the PVC. This is where the HV + lead will exit from the lamp holder assembly. It will pass through the outer PVC mounting tube. I hope it is flexible enough:


    For HV isolation, the closest point between the high voltage and the parts that need to be HV safe will be a 0.500" air gap. This is about 4x the arc gap distance. This clearance will exist between the screw which retains the HV lead to the bottom of the heat sink, and the center of bottom surface in the above x,y plate. I could add a plastic baffle here if this is insufficient, but airflow would suffer. I will probably make a plastic cap to cover the fastener, to improve the resistance at this path without blocking much air. HV only exists in the circuit for a fraction of a second while the 'ignite' button is pushed, and the only metal which is potentially exposed via this path is the x,y,z assembly, not the frame or reflector. So, exposure risk is pretty low, but I would like to maximize the isolation within design limitations, of course. Still, an important safety consideration will be to never attempt to strike the lamp while adjusting it's position.

    Today I will work on heat sink machining.
    Last edited by JP Labs; 11-03-2014 at 10:20 AM.
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    Flashaholic JP Labs's Avatar
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    Default Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.

    One slight concern for me now is that this configuration, with a HV live metal heat sink inside two layers of plastic, inside a grounded metal parabola, is basically a capacitor. Hopefully, it will not be a problem for the power supply to have this added capacitance in the system.
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    Flashaholic* get-lit's Avatar
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    Default Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.

    Ahh.. I didn't realize this is 200W, which may not require forced air cooling. I know 100W doesn't, but I was under the impression that 200W was on the threshold, yet recommended. According to that spec sheet, I'd say convection is fine.


    Yes, if it required forced air cooling, it "should" be air directed onto the seals themselves. A slow steady flow of air perpendicular to the lamp is perfect. The amount of airflow required onto the seals is plenty low enough that it would not negatively affect envelope temperature whatsoever. This kind of air flow was not practical for my configuration. I spent a lot time testing with thermocouple lamps to find a work-around so that inline air flow could be used to cool both seals without over-cooling the envelope.


    If you're sure your lamp doesn't require forced air cooling, then instead of using forced air to cool the HV wire, I'd insulate it with a better material. I'd simply insert the HV wire into solid but bendable PTFE tubing and stick with convection cooling.
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    Default Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.

    Quote Originally Posted by get-lit View Post
    Ahh.. I didn't realize this is 200W, which may not require forced air cooling. I know 100W doesn't, but I was under the impression that 200W was on the threshold, yet recommended. According to that spec sheet, I'd say convection is fine.


    Yes, if it required forced air cooling, it "should" be air directed onto the seals themselves. A slow steady flow of air perpendicular to the lamp is perfect. The amount of airflow required onto the seals is plenty low enough that it would not negatively affect envelope temperature whatsoever. This kind of air flow was not practical for my configuration. I spent a lot time testing with thermocouple lamps to find a work-around so that inline air flow could be used to cool both seals without over-cooling the envelope.


    If you're sure your lamp doesn't require forced air cooling, then instead of using forced air to cool the HV wire, I'd insulate it with a better material. I'd simply insert the HV wire into solid but bendable PTFE tubing and stick with convection cooling.
    Yes, with this power supply, 200W is about as big a lamp as I can run. I may try the HBO100 at some point, too. That model has the highest surface brightness, by a pretty wide margin. It will be interesting to see if that is visibly better than the 200.

    It is the lamp mount, made from a heat sink, that I am trying to insulate against HV leakage. Not the HV wire, itself. That is 50 kV High Tension lead.
    Last edited by JP Labs; 11-03-2014 at 06:59 PM.
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    Default Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.

    OK, I did some more work today. Here is the heatsink, bottom view. The OD is turned down, there is a step to fit the PVC collar, and a screw for the Anode wire is fitted:


    That screw is aligned to be accessible through one of the cooling holes. I made a longer plastic part so the air gap from that screw to the metal plate is increased to 1":


    Lamp fitted. This assembly is the same diameter as the hole in the reflector.

    It is now evident that the silvered section at the bottom of the lamp envelope will shadow a pretty large portion of the parabola, perhaps a 6" circle in the center. This may be a critical flaw.

    Is there any way to partially remove this silvering?




    Added a brass disc to direct the exit air outwards, instead of at the lamp:


    Here it is mounted on the x,y,z positioner:


    In this shot, it has been assembled to the mounting tube, which inserts into the parabola's threaded sleeve:


    Like this:


    Next step, add a cutout and mount the blower. Also the anode wire. Blower goes about here:


    Note that these PVC parts were machined on nearly all surfaces. ID, OD, ends. They were convenient donor material. It would not be an easy task to turn tubes from solid Nylon stock, and plastic tubing in the right sizes and materials was elusive. This worked well, so far at least. We will see how it holds out once I turn up the heat.
    Last edited by JP Labs; 11-03-2014 at 07:15 PM.
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    Default Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.

    It's turning out very nicely. The lamp reflective coating is internal. There may be a version of the lamp available without that coating.
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    Default Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.

    Your above post was fun to go through. Anxious to see it lit and the long range beam shots.
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    Default Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.

    Me too! Beam shots may be a while. At least from anyplace remote where I can hit any distant targets. After several hours more work I should be able to bench test it to get some temperature measurements, though.

    I'm going to need to make some kind of a cart to support this heavy rig, rather than the tripod I currently use. I intentionally mounted the light above eye level in the prior iteration, to prevent folks from looking inside while it's aimed straight up in beacon mode. I should do that again.

    Of course, I still need to check the PS on inverter power, too. I don't have the guts to try that yet; need to at least run it on grid power for a while first - it would be sad to kill this PS so soon!

    I did finally order some 50kV cable to extend the leads. I need to figure out how to go about splicing this safely, if I want to keep the stock PS and ignitor connections. Or, maybe I can un-crimp and re-crimp the rather unique terminals to make new wire runs with the old connectors. Can this stuff be soldered, or is crimping required?

    More thoughts on the reflective area of the lamp:
    While I was surprised to see how much of the reflector will be in shadow, I guess it is not so bad. I had been thinking of it only as a loss in lumens, but really, I am still using the 'best' part of the reflector - the larger diameter portion. And the variation in distance from arc over the usable portion of the reflector will be less than if I used the entire reflector. So, optically, it should colimate even better than if the entire surface was used. The unfortunate part is that a significant portion of the lamps output is redirected outward by that internal reflective area, so lumen utilization is not so good and spill will be greater. BVH encouraged me not to worry too much about this earlier, and I am starting to understand why.

    If I could invert the lamp to put the reflector at the top, that would increase Lumens focused, and would reduce the unfocused light output. The lamp is nearly symmetrical and is optionally rated for AC use, so it might last a while that way, especially if I started the lamp in proper orientation (pointed at the ground in this case) when heating the mercury condensed at the bottom Anode is critical. It could be rotated it upright after warm-up, and pointed down again for shutdown and cooling. This should work fine for horizontal use, but for aiming straight up, maybe not. Lamp is not rated for inverted use in any circumstances, but perhaps that is due to starting and shutdown orientation requirements.

    Also, with the lamp installed upside down, the cathode end would be cooled, not the anode. Combining that with the inverted orientation could be pushing the thermal conditions too far. I don't dare try any of this for a while. Maybe if output is disappointing - which I am not thinking will be a problem!

    One more thing - while the tempered glass cover lens "probably blocks enough UV to be relatively safe", that is not good enough for me. I also ordered a sheet of clear UV filtering 'window security film' in 4 mil thickness. I will laminate that to the outside of the cover lens. It will ensure the UV A and B are at low levels. I may lose another 5-10% output (wild guess) but it seems a prudent measure. That film will help contain the glass in case of breakage, too. Unfortunately, it will scratch easily if on the outside, but I don't think it would survive for long on the inside surface, with rampant UV levels.
    Last edited by JP Labs; 11-04-2014 at 11:04 AM.
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  22. #112
    Flashaholic* FRITZHID's Avatar
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    Default Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.

    In my experience, splicing HV wires is very risky... each splice, no matter how well done, is a weak point.... the slightest gap or air space is a point of failure... I suggest total replacement.....
    That being said, I HAVE used adhesive heatshrink tubing in multiple layers on HV but it makes the wire bulky and can cause gasoff issues in some cases.
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  23. #113
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    Default Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.

    I recently came across a bunch of clear shrink tube I bought years ago that is KV rated. I was going to toss it....but just couldn't so I still have it. I don't remember much about it so I'll try to find it again to get a brand name or other info so I can look up the specs. If the specs are good enough, you can have some of it. As Fritz has done....I've spliced quite a few HV wire runs and used 4 layers of non-adheasive shrink tube with success. Mostly with automotive ballasts applications, including a couple of 80 Watt Blitz HID conversions which strike somewhere around 30 to 35 KV.

    The only Short Arc lamps I have seen that utilize heat sinks at one or both ends are the Cermax/Luxtel ceramic body lamps. I've not seen one conventional SA lamp with a heat sink in either convection or forced air cooling applications. You might be over-engineering this, but that's just a shot from the hip, so to speak. Maybe take some temp measurements with an IR Thermo and see where you're at.

    Just a quick search returned this 36KV rated tube for bus bars.

    http://www.shrink-tubing.com.tw/high...ubing/hb3.html
    Last edited by BVH; 11-04-2014 at 12:32 PM.
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  24. #114
    Flashaholic JP Labs's Avatar
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    Default Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.

    Thanks for the splicing comments.

    Yes, I am probably over engineering it! That's half the fun. I want a vented enclosure, so may as well make the most of the airflow, too.

    The heatsink and plastic are both non-black surfaces, so won't read accurately on IR unless I paint them. I will stick an insulated thermocouple onto the plastic/heatsink junction to check temp.

    I did get the blower mounted and the anode wire installed. Then I blew all the dust out with 90 psi, and blew up my blower's wheel. I grafted the axial fan on for a test, and it works OK, but it's loud. I will get another blower. But this will work for testing.

    Next step, bench test the lamp & mount assembly. Might be a little while.
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    Default Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.

    I finished the fan, wiring, and tested the light in the shop tonight. I'll get to the pics later. Here's what I learned:

    Once I thought about it, I couldn't measure temperature as intended - the heat sink is live and the thermocouple wire is conductive. So, I didn't. Nothing melted.

    This HBO lamp does NOT like much cooling. With the blower on, the lamp would strike fine, but would not warm up. It got to about 50W and stopped climbing. I reduced airflow to about half, but that didn't help much. So I turned the fan off. Lamp warmed up as normal, over several more minutes. At 200W, it required 3.3A. Turned fan back on, power began to slowly drop again. But at only 3.4A, it stabilized at 200W again, working fine. Rated amperage is 3.6A, so mine is still running a little low. Probably not significantly overcooled, at least, as more cooling drives amperage up to maintain power.

    With the fan on, the ozone smell is pretty strong. I opened the garage door.

    Seems to focus OK. The only thing I could hit from the shop was a transformer on a pole, maybe 25 yards away.

    The spotlight runs fine pointed straight up. Decent at 45. But it won't run horizontal!

    It acts like it cools off again. It dims over a minute or two, power dropping, voltage dropping, amps constant as set.

    Stopping the fan didn't help. Cranking the amps did help a little, but I only went up to 4.1A. That is 14% more than rated, and 24% more that it required to run vertically. This allowed it to stabilize at about 90 Watts. Output was significantly reduced. No visible flickering or anything odd. It behaved like it does when too cool. Very low voltage, about 22V - another indication that the mercury pressure is too low, thus not hot enough.

    Lamp looks fine after shutdown.

    I did find conflicting info about orientation for the HBO when I was researching it. One spec sheet said S90, one said S45. I guess S45 is correct (+/- 45 deg).

    Has anybody else actually used an HBO lamp in a spotlight? If so, did this occur? Any suggestions?

    If not, are there any known short arc Hg lamps that WILL work both horizontal and vertical? What DC SA lamps work, in general?

    I know I've seen beamshots taken horzontally in the short arc threads, but I don't remember any discussion of the stability of lamp operation in that orientation. Or anybody that specifically used a super high pressure Hg type lamp, really. Xenon, yes.

    Maybe I just need to crank the amps, readjust every time it's aimed? Cumbersome. Don't want to blow the bulb. The L2 version of the lamp (kind of like an LED bin, I think. The lower end of the voltage variation) runs at 4.2A for the same 200W. I think 10-15% overcurrent is within reason, so maybe I could try as much as 4.8A without worry.

    I think the Xenon lamps are better for horizontal output, right? Lot fewer lumens though.

    I wonder how badly my new MSR400SA would behave, driven on DC.

    3rd lamp tried. 2nd failure. Discouraged.
    Last edited by JP Labs; 11-08-2014 at 08:22 PM.
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  26. #116
    Flashaholic JP Labs's Avatar
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    Default Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.

    Here's the air inlet:


    Blower mounted:


    Filter added:


    There was noticeable air motion at the lamp envelope, so I added a bigger air deflector around the base:




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  27. #117
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    Default Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.

    I only made one HV splice on each cable, for the Ignitor connectors. I am confident it is adequate. Overkill, I think. Here's how I did it:

    Load 4x heat shrink on each cable.


    Solder:


    Rubber tape:


    Liquid Insulation:


    Slit vacuum line:


    Then another layer of the liquid insulation, then the heat shrink:


    Ready to go:
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  28. #118
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    Default Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.

    Great pics. I have only 1 HgXe and that is the 300 Watt Locator. It runs fine from 5 degrees below horizon to vertical. It uses a small fan to recirculate the air within the glass dome. No air is exchanged.

    Today, I did some high voltage wire splicing of my own on the Target Source. I used 5 layers of non-adheasive heat shrink with no issues. My closest distance from + to - is about 5/8".
    WWII 60" Carbon Arc (Sold), 1.6KW NightSun, 1KW VSS-3A, .8KW TrakkaBeam, 600W M-134 Light, 500W X-500-14s, 500W Starburst, 500W A120b, 450 Watt AEG German Leopard 1 Tank Light, 300W Locators, Megaray, 150W Communicator, Maxabeam Gen3, Pichel 75W Mini-Novas

  29. #119
    Flashaholic JP Labs's Avatar
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    Default Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.

    I laid polycarbonate sheeting over the light to kill any UV while running it inside:




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  30. #120
    Flashaholic JP Labs's Avatar
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    Default Re: Scored a Nice 16" Parabolic Reflector. HID or Short Arc? Test Beamshots w/ HID.

    Quote Originally Posted by BVH View Post
    Great pics. I have only 1 HgXe and that is the 300 Watt Locator. It runs fine from 5 degrees below horizon to vertical. It uses a small fan to recirculate the air within the glass dome. No air is exchanged.

    Today, I did some high voltage wire splicing of my own on the Target Source. I used 5 layers of non-adheasive heat shrink with no issues. My closest distance from + to - is about 5/8".
    What specific lamp does your locator use?
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