Ichthyoid (Bill)-Riddle me this LED question please!

[grouper therapy]

grouper therapy;702971 wrote: output of the 3 fixtures / by output of the 4 fixtures = % of par from each fixture
or total number of original fixtures/ total number of future fixtures = % of par from each.

assuming output is linear.

 

[acroholic]

Ripped Tide;702953 wrote: How do you have the 9 currently arranged? Would it be difficult to incorporate the other three? I was thinking about your tank the other day and wondering how you had the lights set up. What are the dimensions of that tank?

Tank is 72" x 36." With top trim, the tank is basically broken up into three 24" x 36" sections, so I have the modules running sideways front to back. Pic is easier. Here:
<fieldset class="gc-fieldset">
<legend> Attached files </legend>

>

class="gc-images" title="CIMG4630.jpg[/IMG] style="max-width:300px" /></a> </fieldset>

 

[johniii]

Ok you guys are entirely too smart for me. Y'all make my brain hurt.

 

[rdnelson]

Very interesting. After 30+ years in electrical construction, this is a whole new side of lighting for me. LOL Kind of makes the Foot Candle look wimpy. LOL

Bill, I am curious where your office is located. We just finished the expansion of a medical manufacturers local distribution and repair facility in Marietta.

 

[rdnelson]

Ripped Tide;702945 wrote:

During a normal electrical current, is there still significant electron exchange? Wouldn't this cause the particles to decay over time? How could the rate of decay be determined? And if there is no decay, there has to be some molecular change, right?

The flow of current in an electrical circuit is in essence the flow of electrons. In simple direct current, an electron is forced into the circuit from the source (say a battery). This electron is accepted by an atom of the conducting material. Because the conducting material resists the forced change to it's atomic make up, it will in turn give off an electron to it's neighboring atom. This sets up a chain reaction. In Alternating Current, this process is continually revised (60 times per second in the US). The ability of a certain material to accept or give up electrons determines it's usefulness as a conductor or an insulator. If the outer orbit of electrons contains 7 electrons it is extremely stable and will not give up or receive electrons easily making it a good insulator. If on the other hand, it has 3 or 4 electrons, it is constantly trying to achieve 7. This means it will easily accept the addition of another electron. This is why Gold and Silver are such good conductors.

Now from a stand point of light, the electrons never leave the conducting material which means there is no degradation of the conductor. What does happen is, if the flow of electrons is inhibited, it will generate heat. This heat is what causes the tungsten filament in an incandescent lamp to glow and give off photons. In fluorsescent lamps, the flow of electricity through a gas will cause the gas to ionize and in turn glow. As for LED, they are new enough to my industry that I have not researched how they actually generator the photons.

 

[ripped tide]

Rich, thanks for the explanation. I was under the impression that corrosion would occur under long term exposure to an electrical current. (that was my explanation to my self why old wires that have been completely enclosed from weather still become brittle and break easily.)

Dave, it looks like those lights line up perfectly on the 300. Would you rotate them all to accommodate the additional modules?

 

[rdnelson]

No problem. The biggest cause of fatigue in old wiring has more to do with heat than anything. As current raises and lowers so does the heat that is generated by it. Continued changes in a materials temperature can change the molecular sturcture somewhat. It will also cause the materials to expand and contract. That was what the big problem was with the aluminum wiring manufactured in the 70s. Because it expanded and contracted so much with the changes in temp, it would cause loose connections at the termination points. Today, it is manufactured with a much more stable aluminum alloy which elevates the bulk of that.

 

[ichthyoid]

This illustrates very simply how electrons lose energy by releasing photons.

<div class="gc_ifarem_title">Atomic Emission Animation - YouTube</div>

This happens by the same mechanism, regardless of the substance that gets excited, whether it be solid, liquid or gas.

LED's and most light bulbs are solids, flourescent tubes use mercury which has been 'boiled' into gas form within the tube, and 'glowsticks' use liquids which also release photons during a chemical reaction.

The ways different substances get 'excited' varies also. Some are excited by electrical conduction, some by getting irradiated by light, nuclear energy, etc., and others via a chemical reaction (glowsticks), as examples.

 

[ripped tide]

So, with different levels of energy being release, will this have an influence of the spectrum of light?

That being said, and if the answer is yes, could I produce different spectrums from one conducting medium by changing levels of energy fed to the medium? Or does spectrum come from type of conducting medium that you are using to produce the light?

 

[ichthyoid]

Wavelength is determined by the specific material being excited and what 'transitions' can occur (are allowed by quantum mechanics).

In metal halide, flourescent and 'white' LED's there are phosphors that are responsible for the 'visible' spectrum

In the case of the MH and flourescent the phosphor absorbs UV and releases longer wavelengths in the visible spectrum.

With white LED's, there is a 'blue' LED encased in a phosphor as well. The phosphor absorbs the blue (~455nM) and 'glows' or flouresces with visible wavelengths, just like the other two lights above.

LED's are just more efficient at producing the light from electricity, because they are solid state semiconductors. Just like transistors are more efficient than vacuum tubes.

The MH lamp is the 'vacuum tube' of the lighting world. It may not be very efficient, but when it comes to producing large volumes of white light, it could not be beaten until the advent of high power LED's.

 

[falos]

I thank lasers are the only form of light that can change color by increse- decrease of current part due to the cooling devises used as far as light we use for reef tanks the color is usuly prodused by the element there filled with being burned

 

[ichthyoid]

falos;703016 wrote: I thank lasers are the only form of light that can change color by increse- decrease of current part due to the cooling devises used as far as light we use for reef tanks the color is usuly prodused by the element there filled with being burned

The only laser that is 'tunable' with regard to wavelength is a 'free electron' laser. They are incredibly expensive and complex.

In lamps the 'color' is produced by phosphors as I described above. There IS a dependence on the elements used to manufacture the phosphors, for colors/spectrum emitted. Phosphor blends are the 'trade secrets' of lamp manufacturers. This is why you can pay over $100 for a MH light bulb. They actual materials used to make them only cost a couple of bucks.

Also- The elements do not get 'burned' in lamps, in the conventional sense. It is tempting to think so, because the lamp will darken and turn black with age. That is due to other reasons.

 

[grouper therapy]

Dave
In any scenario where more identical outlets are added and equilibrium is assured of the outlets, you simply divide the # of outlets you have by the # of outlets want to have and that will give you the percentage of the total that each outlet will need to produce. Goes for valves ,openings, etc.

 

[acroholic]

Ripped Tide;703000 wrote: Dave, it looks like those lights line up perfectly on the 300. Would you rotate them all to accommodate the additional modules?

They line up pretty well thanks to a plumb bob and using a measuring tape on the tank frame itself. Drilled the module hanger holes after the steel frame was installed.

If I use the extra three modules, I'd just slide one on the front end of each set of rails, respace them, and run all 12 of them at 75% instead of nine at 100%.

Edit:

grouper therapy;703019 wrote: Dave
In any scenario where more identical outlets are added and equilibrium is assured of the outlets, you simply divide the # of outlets you have by the # of outlets want to have and that will give you the percentage of the total that each outlet will need to produce. Goes for valves ,openings, etc.

Thanks Dave. I was kind of hung up on the light overlap aspect of it.

 

[enderg60]

Acroholic;702842 wrote: I can't think of anyone more qualified to answer this than you, but if anyone else knows please feel free to post. I had someone ask me this via PM on another forum and I told them I'd try to find the answer.

Let's say you are running LEDs, and they are all the same, and are dimmable percentage wise. You have three units running, and you want to add a 4th. How do you keep the intensity level (PAR I guess) the same as 3 units after you add a 4th? Example, you run the 3 at 100%, a 4th unit adds 1/3 more total light, so do you dim the now 4 units by 1/3 down to 66% from 100%? Or is there more to it than this? I know with more units over a given tank space there will be more light overlap, etc.

Or is this basically a get a PAR meter and measure points on the reef and set your intensity level accordingly?

once again I have no idea how a thread like this can get so long.

you have 3 fixtures at 100% and want the same amount of light with 4.

3 x 100% = 300%
300% / 4 = 75%

so running all 4 at 75% will be the same amount of light as 3 at 100%.

 

[grouper therapy]

Acroholic;703044 wrote: They line up pretty well thanks to a plumb bob and using a measuring tape on the tank frame itself. Drilled the module hanger holes after the steel frame was installed.

If I use the extra three modules, I'd just slide one on the front end of each set of rails, respace them, and run all 12 of them at 75% instead of nine at 100%.

Edit:

Thanks Dave. I was kind of hung up on the light overlap aspect of it.

Yea that is a different question there for sure. Lots of variables to that one. I'd like to see that formula with water clarity. surface agitation. etc. all factored in.

 

[thesilence87]

Can I tack on a question too, Bill? I'm looking to possibly switch to LED's, and I was wondering if there were any units that you would consider usable in the $100-$200 price range. I'm looking to use a single unit to light a 40g breeder.

 

[mojo]

ichthyoid;702891 wrote: Actually this isn't too difficult of a problem, if we stop to think about what we are trying to determine. You may rememeber ratios and proportions from algebra (boooo, hisss from the crowd). Well this is a proportion. It goes something like this-

We know that we have 3 fixtures and they equal 100% of whatever light/PAR we get. We would like to duplicate that using 4 fixtures, so we write it like this-

Except it's not quite that simple. Having four 100w light bulbs isn't the same as having a 400w light bulb. Instead, it follows the inverse square law (yes, ISL is typically used for distance from a light source, but also applies to multiplicatives of light).

Four lights instead of one light would be three times as much light. Eight lights would be four times as much light.

 

[grouper therapy]

mojo;703383 wrote: Except it's not quite that simple. Having four 100w light bulbs isn't the same as having a 400w light bulb. Instead, it follows the inverse square law (yes, ISL is typically used for distance from a light source, but also applies to multiplicatives of light).

Four lights instead of one light would be three times as much light. Eight lights would be four times as much light.

That would only apply if the light was focused in the exact same area. Correct?

 

[mojo]

grouper therapy;703393 wrote: That would only apply if the light was focused in the exact same area. Correct?

From my understanding, it'd apply in the situation that Dave was originally asking about. He wanted to know what percentage to dim his lights so that thee lights would generate the same amount of as four in his tank.

I believe the answer to his question would be "not enough dimming to worry about"...