MH Ballast Power Draws
 

Hi there,

I was just wondering what the normal power draw should be on a magnetic ballast 250 watt DE bulb should be? I noticed tonight that one of the bulbs had blown a fuse on my profilux power bar so I hooked it up to a watt meter and found that it's drawing a consistent 420-430 watts after the start up phase. This seemed really high to me so I checked the other one and it's reading the same thing.

They're both factory magnetic ballasts on a geisseman fixture and the fact that they are both reading identical draws makes me want to rule out a faulty ballast (Pretty slim odds that both are pooched but you never know).

So, are these normal draws? I had been expecting in the neighbourhood of 300-350 but maybe I just pulled that number out of my butt.

Thanks

Been a while since I checked but believe my 250W PFO was around 300W

Measure how many amps they are drawing.

IIRC, 5.5 amps.

Peak amps was 7.1, once it settled down 5 and change seems to be the number I'm remembering

sounds a tiny bit high but now unreasonable, usaly they are around 400ish

Steve

That's a bit high for an HQI ballast, but not ridiculous. Is it more than a few years old?

If you want to save some electricity at the cost of some PAR go with electronic ballasts which will draw as advertised. Electronics are also smaller, lighter, run cooler and silent but they do cost more.

http://www.fortunecity.com/meltingpo...ie/38/id53.htm

What does the capacitor do in the ballast circuit?
The capacitor controls the power. Making the ballast more efficient (HPF).


How do you know when the capacitor has gone bad?

The lamp will not normally work if the ballast circuit is a CW or CWA.
Testing is the only way to know when the capacitor has gone bad on HX-HPF and R ballast circuits. On HX-HPF and R the amp draw will almost double when the capacitor fails.

Bryan: The site you linked to prompts a warning message that it has been flagged as an attack site by google/firefox

Fkshiu: The current ballasts are at least 3 or 4 years old but I am not sure of the exact age since I bought the fixture used.

I have considered E-ballasts and done some looking at Sanjay's site, I am unsure how much a drop in Par will affect my tank, all of my sps' are up in the top 8" of water and I have no plans to populate the bottom with sps.

My other concern with E-Ballasts would be interference, I seem to remember reading somewhere that electro magnetic interference has been an issue with these, the ballasts would be about 4 feet from my profilux controller and 5 feet from the lcd tv/stereo/bluray set up. Any thoughts?