Halide/Ballast Question

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biotoxin

Aquarium Advice Freak
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Sep 21, 2003
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I know this is probably a stupid question but...i ordered a 70w ushio halide but i was unaware its really 75w. My ballast is rated at 70w's is that gona present a problem if i wana run this bulb?
 
I don't think so...it should light it with no problem. 70w is a common size in MH and I'm pretty sure Ushio wouldn't put out a bulb that the 70w ballasts wouldn't light. Just my bet guess.
 
Hi,

My recomendation would be to get the proper bulb or balast. While the 70w unit may light the bulb it will run it at very reduced effeciancy. This is because gas discharge bulbs are very, very current sensitive. In fact, the ballast's primary job is to exactly regulate the amount of current required by the gas contents in a particularly rated and matched bulb. If there was no ballast, most gas discharge type bulbs would explode - i.e. the supply of electrons would be limitless and the gases in the bulbs would become over ionized and flooded with electrons until the gases in the bulb underwent a chemical reaction that might cause an explosion.

BTW, a magnetic ballast controls the flow of current by using a magnetic coil while an electronic ballast uses an electronic current sensing circut to know how much voltage it should apply to the lamps electrodes. This precise control of current through the gases is what keeps the bulbs elctron collisions at the right rate to cause them to emit the proper amount of photons.

Bottom line - first, the 70w ballast may have difficulty starting the bulb, secondly, even if it starts it, it is likely to do so over a longer period of time exposing the bulbs electrodes to greater wear and tear, and thirdly, it is not likely to regulate the current through the bulb properly resulting in decreased output spectrum and power.

HTH

Tom
 
I need to add something:

If for some reason it does work out, you're obviously going to break some law of physics thus causing the planet to be destroyed in some unholy manner. So you have to ask yourself, is 5W really worth it?

Jim

oh yeah, if anything stated here is inaccurate, please feel free to correct me :lol:
 
i contacted aromat and they said the bulb would run fine. I realize the bulb might be run at a reduced rate but i really dont see the signifcance of 5w. Also, its a monumental waste of time for me to try and find a new bulb and ballast since i've already invested too much time and money into this. I ordered that bulb under the pretense of it being 70w thus the model number : UH-70AQ.
 
Yep - Like I mentioned - it will likely work - though there will be some reduced performance and likely reduced life of the bulb. Assume they told you that - BTW it is a little important depending on whether it is a magnetic ballast or an electronic ballast.

Did you ask them if they would honor the warranty if you were running it with 75W bulbs? (not that you would tell them that if it broke :) )

You might also want to ask them if it's protected by a fuse (naturally it must be) and at what current level will the fuse blow? I also noticed in their spec sheet that it mentions that it's 70W output at 120VAC but many residences operate at 100 VAC (typically based on location yours could be anything from about 95 to 120). So at 100 VAC will it still be able to generate 70W, or will it drop to perhaps 65 watts? Just some thoughts if you want to be sure of its long term use.

BTW - cool site.

None the less - Go for it if you've got other constraints :)

Tom
 
actually i just talked to a technical rep for aromat for about 30 mins who told me that the ballast fires at a continuous 70w so the 75w bulb wouldnt pull off more than the ballast can handle. He also said that since its running at 70w instead of 75 that i would actually see an increase in bulb life since high wattage degrades the contacts more. The bulb functions within a 5% range and for it to run @70w is not harmful to the bulb or the ballast. He also mentioned that ushio said that their bulbs would fire at 70w and wouldnt harm them since its not firing at a full 75w the bulb is still within its recommended tolerances.
 
Sort of like asking a chrysler salesperson if their cars perform as good as BMW :)

Yep - could be - I'd still be a bit skeptical as it is the initial start-up that wears the anode's in these bulbs. It is clear that the bulb will not draw any more than the ballast can supply, in fact that exactly seems to be the problem. The power available for start-up (this is where the elements in the bulb ionize the gases in the bulb and supplies the neccessary free electrons for continuous light) is what predominantly wears the elements down. Since these elements are specifically engineered to handle specific amounts of current evenly - it is likely that there will be a change in the elements performance (it may develop a hot spot that wears, or the full element will not be energized, etc.). But after all - we're only talking about 8% difference.

Warranty - affected by this?

BTW - Just my opinion, Half truth: Higher wattage definitely wears elements quicker, because Ballast will fire the elements with a greater amount of current than the element was designed to handle. But the proper current does not. Lower current may, as it will take longer to reach the operating level of the bulb it is accompanied with. There is a reason why these devices are designed and rated for specific values. They may work outside those - but rarely optimally.

Also really, I'm not here to argue for you with someone who gets paid to tell you great stuff about his product... So as I said before:

If you've got the constraints - and you need to use this one - and they told you everything is ok - go for it.

Tom
 
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