form109
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just wondering is it possible to remote ballast a high pressure sodium lamp?
does the ignitor have to be close to the lamp to reliably ignite the lamp?
if not so will using heavy guage wiring make it possible?
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gmercury2000
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You can but I believe the ignitor is supposed to be within 2 ft of the lamp.
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form109
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if its more than 2ft away from the lamp will the ignitor be strained and have a harder time igniting the lamp.
does this have anything to do with voltage drop as distance increases.
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Mercury Man
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With alternating current there should not be a voltage drop because of distance, this only occurs with direct current. I have remotely ballasted an HPS lamp with the ballast/ignitor about six feet away and the lamp started up fine. Would it be any different than remotely ballasting a fluorescent lamp, and having a preheat ballast with the starter mounted further away from the lamp?
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lightman64
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Zero 88 Lighting Controls Rule!
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yes, there is no problem with remote ballasting a HPS lamp.
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The future of street lighting is Induction, not nasty HPS lights or cr@ppy LED lights! Preheat CFL's should make a comeback!
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TudorWhiz
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We have remote HPS clamshells in Frederick, and the ignitors are mounted on the arm
Also they DO make series HPS ballasts!
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For pictures of my streetlight collection and other streetlight pictures with some various pictures that are not in this website, please visit http://www.galleryoflights.org/ under GullWhiz
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form109
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With alternating current there should not be a voltage drop because of distance, this only occurs with direct current. I have remotely ballasted an HPS lamp with the ballast/ignitor about six feet away and the lamp started up fine. Would it be any different than remotely ballasting a fluorescent lamp, and having a preheat ballast with the starter mounted further away from the lamp?
i believe a certain amount of voltage drop occurs in all circuits,weather they be AC or DC,the distance between the lamp,ballast and ignitor is usually not long enough to cause a noticable voltage drop. @brian actually direct current has less voltage drop than ac,as Direct Current is currently being utilized for power transmission in a few parts of the world,including the united states.
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DimBulb
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I thought there was much more loss over distance with DC than AC. Isn't that why Tesla's alternating current won out over Edison's direct current? Power plants could be located further away with AC.
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My very first word was LIGHT!
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form109
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Alternating Current won cause it is cheaper to generate and transmit,Direct Current has two lines,while Alternating Current has three,this lower cost of line construction in DC Lines is offset by the cost of rectifiers and static inverter's.
in direct current power transmission the AC is converted to DC by Rectifiers,older installations used Mercury Arc Rectifiers,newer installations use Solid State Rectifiers,the DC is then converted back to Ac with inverters.
its relatively simple to convert AC to DC,however it is expensive to convert DC to AC.
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« Last Edit: January 10, 2009, 09:50:55 AM by form109 »
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SeanB~1
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AC is easier to transport over long distance, using simple transformers to change voltage, but DC can carry higher power for the same peak voltage ( This is determined by brakdown voltage, AC voltage is measured in RMS units, generally the peak is 1.414 times that for a pure sine wave) but needs more sophisticated equipment to convert.
As to the ignitors, they generate a high voltage pulse to start the lamps, and this pulse has a relatively low energy, so any long cabling will attenuate the pulse voltage due to capacitive loading, making starting more problematic. You can put a simple series ballast a long way from the lamp, but the 3 wire ignitor must be close to the lamp to get reliable starting.
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Medved
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Semiparalel ignitors are usually rated for much larger cable capacitance to lamp - 2nF (~20m/60foot of regular 3*2.5mm^2 cable) is not as rare value for them. But if the superimposed type fit well close to the lamp, it is better to use it - as you don't have to deal with long cable, run in routed in humid area, stressed to multikV ignition spikes. But when you want to use the (e.g. MH 70W Rx7s) lamp in a lantern originaly designed for incandescent (R7s 300..500W halogen floods), where is usually no place for decent ignitor placement, is better to se a long-range semiparallel one inside the ballast box and better quality cable to the lamp.
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No more selfballasted c***
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