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#1
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fish camp light bulb failure
I would appreciate some help with a 12 volt question.
I set up a 7 light long string of 12 volt, 40 watt bulbs on a strand of 12 guage, outdoor lighting, copper wire. The bulbs and bases were standard Edison screw base types. The lights were connected to a 300 watt DC converter made for outdoor yard lights. In theory, I would like to take the same string (with lower wattage bulbs) on sailing trips. In 4 days, 6 of the seven lights have burned out. One light continues to burn at normal brightness. Any ideas or comments on these failures apprecitated. Thanks Tom |
#2
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fish camp light bulb failure
Overvoltage is my guess....... measure the voltage on any one of the bulbs.
-W "Tom Best" wrote in message om... I would appreciate some help with a 12 volt question. I set up a 7 light long string of 12 volt, 40 watt bulbs on a strand of 12 guage, outdoor lighting, copper wire. The bulbs and bases were standard Edison screw base types. The lights were connected to a 300 watt DC converter made for outdoor yard lights. In theory, I would like to take the same string (with lower wattage bulbs) on sailing trips. In 4 days, 6 of the seven lights have burned out. One light continues to burn at normal brightness. Any ideas or comments on these failures apprecitated. Thanks Tom |
#3
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fish camp light bulb failure
Any ideas or comments on these failures appreciated.
In the time I've spent as an Aviation Electrician, I've seen incandescent bulbs fail for many reasons including: vibration, exposure to temperature extremes, poor quality construction, over voltage, and "hot spots" caused by fingerprints on the globe. If you can eliminate most (or all) of these causes, I'd expect your bulb life to increase. My 2¢ (¯`·._.· £ãrrÿ ·._.·´¯) "Tom Best" wrote in message om... I would appreciate some help with a 12 volt question. I set up a 7 light long string of 12 volt, 40 watt bulbs on a strand of 12 guage, outdoor lighting, copper wire. The bulbs and bases were standard Edison screw base types. The lights were connected to a 300 watt DC converter made for outdoor yard lights. In theory, I would like to take the same string (with lower wattage bulbs) on sailing trips. In 4 days, 6 of the seven lights have burned out. One light continues to burn at normal brightness. Any ideas or comments on these failures apprecitated. Thanks Tom |
#4
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fish camp light bulb failure(info)
TOM make sure that your circuit is a parrallel one, not in series.Also you
cannot reduce the watt of the bulb because you will reduce the resistance of your circuit and let pass to much current on the same bulb (burning action) "Tom Best" a écrit dans le message de om... I would appreciate some help with a 12 volt question. I set up a 7 light long string of 12 volt, 40 watt bulbs on a strand of 12 guage, outdoor lighting, copper wire. The bulbs and bases were standard Edison screw base types. The lights were connected to a 300 watt DC converter made for outdoor yard lights. In theory, I would like to take the same string (with lower wattage bulbs) on sailing trips. In 4 days, 6 of the seven lights have burned out. One light continues to burn at normal brightness. Any ideas or comments on these failures apprecitated. Thanks Tom |
#5
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fish camp light bulb failure(info)
"jean" wrote in message
... TOM make sure that your circuit is a parrallel one, not in series.Also you cannot reduce the watt of the bulb because you will reduce the resistance of your circuit and let pass to much current on the same bulb (burning action) This is incorrect. If you reduce the wattage of the globe, the resistance will INCREASE as it will draw LESS current at the same voltage to get the lower power. ( Power = Voltage*Voltage/Resistance). As the bulbs progressively failed, it is obvious that they must be in parallel as they would all go out if any one failed in a series circuit. regards, Mark |
#6
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fish camp light bulb failure(info)
jean,
I'm confused on what you're saying. 40 watts is the current limit for the bulb, period! Unless of course the voltage is too high thereby forcing more current through. From what I see of these outdoor converters, the voltage output is constant. Manufacturers just don't want you to overdrive them with more wattage of bulbs than the trancformer can put out. -JimL jean wrote: TOM make sure that your circuit is a parrallel one, not in series.Also you cannot reduce the watt of the bulb because you will reduce the resistance of your circuit and let pass to much current on the same bulb (burning action) "Tom Best" a écrit dans le message de om... I would appreciate some help with a 12 volt question. I set up a 7 light long string of 12 volt, 40 watt bulbs on a strand of 12 guage, outdoor lighting, copper wire. The bulbs and bases were standard Edison screw base types. The lights were connected to a 300 watt DC converter made for outdoor yard lights. In theory, I would like to take the same string (with lower wattage bulbs) on sailing trips. In 4 days, 6 of the seven lights have burned out. One light continues to burn at normal brightness. Any ideas or comments on these failures apprecitated. Thanks Tom |
#7
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fish camp light bulb failure(info)
Watts is a measure of power. Current is measured in amperes.
JimL wrote: jean, I'm confused on what you're saying. 40 watts is the current limit for the bulb, period! Unless of course the voltage is too high thereby forcing more current through. From what I see of these outdoor converters, the voltage output is constant. Manufacturers just don't want you to overdrive them with more wattage of bulbs than the trancformer can put out. -JimL jean wrote: TOM make sure that your circuit is a parrallel one, not in series.Also you cannot reduce the watt of the bulb because you will reduce the resistance of your circuit and let pass to much current on the same bulb (burning action) "Tom Best" a écrit dans le message de om... I would appreciate some help with a 12 volt question. I set up a 7 light long string of 12 volt, 40 watt bulbs on a strand of 12 guage, outdoor lighting, copper wire. The bulbs and bases were standard Edison screw base types. The lights were connected to a 300 watt DC converter made for outdoor yard lights. In theory, I would like to take the same string (with lower wattage bulbs) on sailing trips. In 4 days, 6 of the seven lights have burned out. One light continues to burn at normal brightness. Any ideas or comments on these failures apprecitated. Thanks Tom |
#8
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fish camp light bulb failure(info)
jean wrote:
TOM make sure that your circuit is a parrallel one, not in series.Also you cannot reduce the watt of the bulb because you will reduce the resistance of your circuit and let pass to much current on the same bulb (burning action) jean; 1) The original poster stated that he had seven (7) bulbs "in parallel", so that's not an issue. 2) Do not understand your "reduce the watt of the bulb" statement. It appears wrong. If you reduce the wattage LESS current will flow (Volts x current = watts). And the resistance will INCREASE. Basic Ohms Law! Example: 12 volts x 1 amp = 12 watts. Resistance of lamp is Volts/Amp = 12/1 = 12 ohms. Example: 12 volts x 2 amps = 24 watts. Resistance of lamp is .......12/2 = 6 ohms. Thus: Twice the resistance results in half the wattage. |
#9
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fish camp light bulb failure(info)
Thanks for the info. Small (important?) corrections and additional
info follows: Seven bulbs in paralled and are 25 watts, not 40 watts. Resulting in a total of 175 watts on a 300 watt transformer. However, one bulb still burns at regular brightness. The copper wire is 12 guage and stranded. About 30 feet long. I though the low voltage yard lights were transformed to 12 volt DC not 12 volt AC. Is that the issue? Tom |
#10
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fish camp light bulb failure(info)
"Tom Best" wrote in message om... I though the low voltage yard lights were transformed to 12 volt DC not 12 volt AC. Is that the issue? The light bulb would not care if it got 12 VDC or 12VAC. It might help if you provided more detail on the "DC Converter". Why are you using a DC converter instead of a simple AC transformer? You said it was made for this so one would assume the voltage is correct, but you should measure it anyway. Have the lights been on 24 hours a day, or just a few hours each evening? Light bulbs are rated in number of hours they can be expected to last. Some light bulbs will last thousands of hours. Others, like a projector bulb for example, may last only tens of hours. Heat, shock and vibration are reasons for premature bulb failure. Some bulbs are not rated to operate in an "upside down" position, as it will cause the base to overheat. Make sure that the bulb is not being used in an inappropriate application. Perhaps if you told us exactly what bulbs you were using it would help. You said they were in a screw base, are these the 12volt bulbs that are often used in RVs or boats? Rod McInnis |
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