Lights keep turning off

[Krugar]

Okay I picked up a 70W ballast from Oliver & a 20K bulb from Ivan.

Wired it up and at first nothing but arcing in the bulb. After reseating the bulb it fired, but now it'll only stay on for about 45 minutes & it shuts down.

I can unplug it & plug it back in & it fires up again.

If I had to guess I'd think static. The fixture's ground is connected to one side of the chasis & the other side of the chasis is connected to the outlet's ground.

Do I need to connect the ground wires & tap off to the chasis instead? Any ideas?

The other thing is the bulb is whiter than I thought it would be to start. I realize bulbs need some burn in time & I only have about 3 hours on this one, anyone with a 70W 20K finding the same?

Cheers!

[ReefSalt]

What type of Ballast? and what gage wire are you using,some electronic ballast are tempermental on wire gage,I had an issue with a good electronic ballast that we were testing,it would fire the bulb then turn off.and then start up again, several min to hrs later(dont recall exactly)
And Yes I would allways connect the ground.20k`s should be a blue tint at start up.

[frank]

make shure your gounds are all connected together also metal halide and mercury vapour bulbs will go on and off because the life of the bulb is over leave your light on and when it goes off let it stay like that for about a half hour if it goes back on most likely your bulb is finish or the wiring is not setup right

[Krugar]

It's a NAIS M7012CK if that helps.

The wiring is a sacrifical grounded extension cord 16/3 rated for 13A & 1625W according to the CSA sticker on it.

My grounds currently look like this:

light --- ballast ---- outlet.

Do I need to wire them like this:

light -----+----- outlet
.............|
..........Ballast

Sorry I'm not terribly good at diagrams.

Thanks!

[Krugar]

I hope the bulb's good, I just picked it up.

I'll connect the grounds together as you suggested Frank & see if that makes any difference.

Thanks!

[IJO]

We've had this happen with a couple other 20k DE's and the one we've tested were very blue... sounds like you got a defect. Bring it back and we'll swap it for another.

IJO

[Krugar]

I thought it should have more blue in it, this one is only blue when it's warming up & then it looks closer to a 10K. But if it takes 100 hours to burn in as Robin suggested that'll be a while.

The fixture's bigger than I thought it was so I'm building yet another canopy. The bulb's only getting test burns right now.

Anyway I just combined my grounds & tapped out to the chasis. I just lit it up to see if that changes anything. I'll let ya know in about 40 more minutes.

Cheers!

[Krugar]

Something else I just noticed, I only have a fan on the fixture but the ballast is thermally protected & is getting pretty warm.

Considering how hot my 400W ballasts gets I didn't think it was a problem, but I've never used one this small. Do I need a fan on it too?

Cheers!

[Krugar]

Well it just shut off again. I'll give you a shout tomorrow to arrange a swap Ivan, thanks!

[Krugar]

The new bulb seems to be working much better. I had it running for about an hour, then I moved it off the tank (easing them into the idea of bright light) & turned it back to get some time on the bulb.

It shut off again in about a half hour, but I'm thinking this could be a fluke. It's now been running for about 1.5 hours after unplugging it & plugging it back in.

Anyway, there's a "nipple" in the middle the tube. Does this go up, down, or does it matter?

Thanks!

[Flame*Angel]

Nipple orientation is irrelavent.

[One Salty Dog]

I am really beginning to wonder about some of these light threads .. .they always end up with a discussion about nipples!!
Rob

[aragorn69]

Very true, nipple orientation may be irrelavent, but I do have a preference, but I won't get into that here. ;-)

[Flame*Angel]

I'm really no expert in this but it really sounds like the problem is more with the ballast or wiring to it than with the bulbs.

Heh, OSD - it is MUCH harder to squash a rumour than start one. I don't know how anyone ever thought that the direction of the nipple could change the light it gives off but it certainly persuaded a lot of people for a long time.

[One Salty Dog]

That's for sure... The dam nipple on all these bulbs is nothing more then where the bulb was attached to a glass rod in the manufacturing stage. Nothing more.
Rob

[Toutouche]

I'm just waiting to see what the next "fad" is in reefing... Perhaps piercing that nipplehttp://mindscraps.com/s/ups/layla_phoenix/boobies.gif on the bulb!!!!!!!:p: ;)

[liv]

its not the ballast as it works great on the 10k and 6.5 k... but if you are convinced it is, i'll swap it with one of mine. i have had them running a few months now.
I also have the same issue with the 20k.

[tang_man_montreal]

Well, I plugged it up again today, and noticed 2 things...

1) After 45 minutes, I still had a hissing sound, until...

2) after 45 minutes, it shut off by itself.

This seems to now be a common issue with the ballast/bulb combo. Is it truly the 20k 70w bulb causing the ballast to shut-off by itself? Or is it a bad ballast? Or is it that they are incompatible?

Ivan, depending on the outcome of this thread, I may need to replace the bulb, the ballast, or both... :(

On a high note, The color of the 20k bulb was exactly what I was looking (while it lasted) for on my frag grow out tank. I hope that I can get a 20k to work with this ballast...

[CableGuy]

I have 2-70 watt ballasts from liv coming with 2-20K bulbs from Ivan, I hope they work. I will let you know what the out come is when they arrive.

[Krugar]

Well I don't know what to say but here's my experience:

Nipple down -> bulb temperature cools to about 10K very quickly and lamp shuts off in 45 minutes to 1 hour.

Nipple up -> bulb temperature still cools to about 10K, but it takes longer. Lamp has run unintterupted for 6 hours.

I have not changed the wiring on the ballast, nor have I swithced ballasts. I have moved the lighting fixture around.

The slower colour shift could easily just be part of the regular "burn in" for the bulb.

I have not tried to duplicate the lamp switching off by moving the bulb to a nipple down position.

I did check that the contacts were good and solid on the lamp in both the nipple up and nipple down positions. I also recheck prior to changing from a nipple down to a nipple up position.

So I don't know what to say here. For mogul based bulbs aside from the Bottum up / Horizontal orientation I can tell you there is no differnce from experience. I've used these bulbs and most don't care if a BU bulb is mounted horizontall or vice versa.

Some however do & I've seen firing problems with the ones that are finicky. Usually these just don't start in the wrong posistion, but I guess it's possible that they'd shut down too, I just haven't personally seen it.

Generally in my experiance I would suspect the bulb in this behaviour, not the ballast. I've discussed it with some friends that have been using HID lighting longer than I have and they also immediately suspected the bulb.

The same hasn't worked for others so it's entirely possible that my second bulb is intermittantly "flakey". Then again I'm told I shouldn't rub zoos on my gums as it produces nasty side effects....

Cheers!

[Toutouche]

Kruger,
Tell you what..., rub some of them there zoos on your gums and it should tell you if the bulb is flaky or not. Nipples have nothing to do with the lighting. (Unless they're dancing and have glitter on 'em..., then lighting can make a HUGE diffference!!).

[Krugar]

If the nipples were dancing and glittery I've either been too close to the zoos or I'm in a lot of trouble with my wife... :)

Ivan's testing some more of the 20K 70W at his place perhaps I just have a flakey bulb still.

Would it help if I got a horse shoe or mounted a rabbit's foot? Mabey if I tied it to a black cat for a while...

Cheers!

[Toutouche]

You could try!! Wouldn't hurt!!