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    bluebottle's Avatar
    bluebottle Posts: 3, Reputation: 1
    New Member
     
    #1

    May 18, 2005, 04:59 AM
    Modifying a HID ballast, spooky!
    Hi chaps,

    I have a 400W Metal Halide bulb and ballast. The bulb socket is permanantly attached to the end of the ballast and the unit is designed to hang vertically from the opposite end of the ballast.
    I would like to separate the ballast from the bulb by two meters. I have opened the ballast and the job is a piece of lolly, physically. The two wire feed from a capacitor inside the ballast to the bulb socket are run through two holes drilled through the entire legth of the transformer plates. I assume this is to save space in the slim, compact design. I speculate this may also be used to set some sort of pulse or timing. I would like to change nothing about this part of the design. My qestion is: Does altering the length of the feed cables (Through the transformer plates) to the bulb socket cause any issues? I plan to use 3 core cable. The third cable used to link the ballast housing and a new metal clip that will hold the bulb socket.

    Give me the thumbs up and it'll be done by the end of the week.

    Cheers

    bluebottle
    labman's Avatar
    labman Posts: 10,580, Reputation: 551
    Uber Member
     
    #2

    May 18, 2005, 09:39 AM
    I don't quite understand how ballasts work. Still, look at the capacitor. I would guess it is closer to a Farad than a micro Farad. 3' of wire is not going to add much capacitance. In computers and RF devices, adding a little wire can eat up all the signal with too much capacitance. The one other problem is RF interference. If something near by has problems, somebody that knows a lot more than I do, will have to help. There is also the matter of an FCC license.

    I like to make my modifications easy to undo. If you had the base from an old bulb, you could use it in the existing base. I am more familiar with metal halide bulbs that use a standard bulb socket. You could also connect things up with alligator clips, the proper size fuse, and see what happens. Be sure and use wire rated for the voltage.
    Flickit's Avatar
    Flickit Posts: 278, Reputation: 2
    Full Member
     
    #3

    May 18, 2005, 10:16 AM
    The dressing of the...
    Quote Originally Posted by labman
    I don't quite understand how ballasts work. Still, look at the capacitor. I would guess it is closer to a Farad than a micro Farad. 3' of wire is not going to add much capacitance. In computers and RF devices, adding a little wire can eat up all the signal with too much capacitance. The one other problem is RF interference. If something near by has problems, somebody that knows a lot more than I do, will have to help. There is also the matter of an FCC license.

    I like to make my modifications easy to undo. If you had the base from an old bulb, you could use it in the existing base. I am more familiar with metal halide bulbs that use a standard bulb socket. You could also connect things up with alligator clips, the proper size fuse, and see what happens. Be sure and use wire rated for the voltage.
    ... wires seem to indicate that the frame and x-former may be part of a shield to prevent the RF spray from causing an FCC/interference problem. If Labman is right and the capacitor is large-valued, then be sure to run the extended wires near a ground plane to make this 'shield' continuous. If you lose some light intensity in the process, it indicates the loss may be due to ground coupling through the extended wiring and that possibly the capacitor is not as large valued as believed to be.
    bluebottle's Avatar
    bluebottle Posts: 3, Reputation: 1
    New Member
     
    #4

    May 18, 2005, 03:18 PM
    Comparing a HPS with remote bulb socket
    Thank you guys,

    I made in error in the subject line of my original quote. HPS (high pressure sodium) should have been HID (High intensity discharge). I have edited my original post.

    I have a HPS system to compare designs. Are the wiring and components similar in design to a metal halide system?
    Flickit's Avatar
    Flickit Posts: 278, Reputation: 2
    Full Member
     
    #5

    May 18, 2005, 03:56 PM
    These are all from...
    Quote Originally Posted by bluebottle
    Thank you guys,

    I made in error in the subject line of my original quote. HPS (high presure sodium) should have been HID (High intensity discharge). I have edited my original post.

    I have a HPS system to compare designs. Are the wiring and components similar in design to a metal halide system?
    ... the same or similar family and the original replies should hold...
    tkrussell's Avatar
    tkrussell Posts: 9,651, Reputation: 724
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    #6

    May 18, 2005, 06:39 PM
    Check with the manufacturer of the ballast you have, the distances range from 10 feet up to 50 feet, depending on the type of HPS ballast you have, and the enclosure of the ballast.

    Remote installation of HID ballasts is not uncommon. Many street lights have the ballast in the large base at street level with the lamp at the top of the 30 or 40 foot pole. This is done for various reasons. One is the fixture can be smaller and light weight and does not need to support the weight of the ballast. This also helps with wind load in areas subjected to high winds often.

    Industrial mill type plants often remote ballasts down lower than the 50 foot high ceiling, again keeping weight down and not having large heavy weights above the plant. Also the heat is greater at these heights in certain industries, and the heat can affect ballast operation.

    The ballast must be installed in a metal enclosure for obvious reasons, protection of the ballast , and containment of sparks should a failure occur.

    The wiring must be the appropriate for the installation. You mention cord. Is this going to be a portable device? Cord shall not be installed permenently in a structure, and cannot offer physical protection of the wiring.

    An equipment ground must connect from the grounded ballast enclosure to the metal shell of the enclosure supporting the lampholder. If you use three wire cable, two for the lamp, and one for the ground , you are all set.


    Wire size may be a factor for voltage drop. If you use a minimum of #12, you will have no problems.


    FYI, all ballasts capacitors are rated in microfarads, size according the ballast wattage to help correct the low power factor of the indctive laod of the transformer.

    Hope this helps. Keep in mind the ballast and lamp operating temperature So be sure the installation is a quality job to protect from fire damage that can be caused by the heaat from each device.
    bluebottle's Avatar
    bluebottle Posts: 3, Reputation: 1
    New Member
     
    #7

    May 23, 2005, 05:06 PM
    Jobs done
    Hi there,

    I've installed about 2m of cable. The light seems to be running sweet. Tempreture seems to be fine.

    Thank you everyone who participated

    bluebottle

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