Metal Halide question

[wbrian63]

I got a new 175w Wobble Light.

For the first few weeks (it's used only on the weekends) it worked just fine. Flip the switch, light flickers a bit and starts to glow. Within 3-5 minutes you've got lots of nice light.

This weekend, it decided it needed a break. Worked fine Saturday AM, and I shut it off about 3p when we ran to the home center for more lumber.

Came back and flipped the switch. No immediate glow, but the lamp was still a bit warm from when it was on before. Expected it to strike off in a few minutes.

Got busy and noticed after 10+ minutes, still no glow. After a few more minutes, I noticed it was glowing, but then shortly after that, it "flashed" and went out again. After 30+ minutes of this behavior, it finally came on full blast.

Today, same behavior, but when I looked more closely, I could see a small glow down in the bulb. Irritation got the better of me and I "tapped" sharply on the bulb cover, and it started glowing, but then repeated the glow for a bit, blink and go out thing. It finally restarted a few minutes later.

I know nothing about the technology involved with these type of lamps. Should I replace the bulb, or is what I'm experiencing the ballast?

Suggestions are welcome.

 

[Norcal]

If you moved it around w/ the lamp on or hot, it could lead to lamp failure.

 

[malibu101]

All HID (high intensity discharge) such as metal halide or high pressure sodium lamps and ballasts have a restrike time when restarting hot. Whether or not power is applied, once you turn it off it needs ~15-20 of cool down time until it starts again. What you are describing I call normal.

 

[wbrian63]

We were gone for about an hour.

Shouldn't that be sufficient time to cool down?

Checking a few online sites seem to point to a bad or failing bulb.

Thinking back, when I unpacked the unit, the bulb came out of the box unexpectedly and dropped 6 or so inches onto the wood floor. It was in a cardboard sleeve and I was initially concerned.

Thinking at the time was, OK, if it doesn't light up, then I buggered the bulb, so off to get another one. However, it did light up so I figured I was good to go.

Possibly not.

As far as the "if you moved it around with the lamp on or hot, could lead to lamp failure" - good to know. It does strike me as somewhat strange that the manufacturer would design a lamp like this that for all the world looks to be "construction site hearty", but lamp it with technology that likes to sit still...

They have a larger 400w metal halide setup, plus a 500w halogen. They used to have a 200w florescent setup, which I was interested in to start. That model has been discontinued - no word why. Possibly a good thing, as the bulb was a proprietary part - not available from anywhere but the manufacturer. I think the same thing holds with the 500w halogen bulb.

I'll pick up a new bulb this week and see if that doesn't cure the problem.

I'll also be careful with placement / movement while the lamp is in use or hot.

Thanks for the opinions - I welcome more...

Regards

 

[Cuda]

Metal Halide bulbs are notorious for being finicky. I have seen them do what you are describing at times, and other times work fine.
An hour is ample time for one of these to cool down and restrike so I don't think that's the problem.
The only Metal Halides I have worked with that are not so finicky are Pulse Start types, and they are usually more expensive.
I'm pretty much hooked on T8 flouescents any more. The light is as good if not better than the HID, not as expensive to run, and doesn't have the cool down issues that HID lights have.

 

[wbrian63]

Agreed about the T8's. We've got them everywhere in the shop - this light is purely for construction/deconstruction type work. The shop is only lit in the main space with T8's. The loft, finishing room, closets, equipment alcove, etc are still getting sheathing, so the electrical hasn't been trimmed out to allow for fixtures to be installed. Soon, soon.

Even still, I've never seen a T8 that comes in a neat "weeble" type housing...

I truly wish that the 200W florescent version of this lamp was still available. For whatever reason, they're no longer manufactured, and I've not been able to find out why.

 

[nehog]

Uh, screw the bulb back in the socket! I've had this happen with my sodium lamps, usually on a six month cycle. Can't for the life of me figure out why they want to unscrew themselves, but they do. We're not talking a tiny bit either, usually two full turns loose!

 

[Brandon_K]

Uh, screw the bulb back in the socket! I've had this happen with my sodium lamps, usually on a six month cycle. Can't for the life of me figure out why they want to unscrew themselves, but they do. We're not talking a tiny bit either, usually two full turns loose!

High frequency harmonics, seriously.

As for the wobble light, it definitely sounds like an indication of a bad bulb. Those bulbs are typically good for thousands of hours, though it's possible it was damaged prior to use.

As far as the bulb, I looked at Wobble Light, there isn't anything special about it. It's a 175w MH with a mogul base. Lowes, Home Depot and any electrical supply house will stock them, usually around $25.

 

[z28toz06]

it sounds like the filament might be loose. When you hit it you may have caused the filament to reattach. I have done this with other incan bulbs before. halides degrade over time. they lose color spectrum and some lumens. I dont remember the "hours" rating but it is in the thousands of hours.

 

[Norcal]

it sounds like the filament might be loose. When you hit it you may have caused the filament to reattach. I have done this with other incan bulbs before. halides degrade over time. they lose color spectrum and some lumens. I dont remember the "hours" rating but it is in the thousands of hours.

There is no "filament" in a metal halide lamp.

 

[NAYLOR]

The arc tube might be loose. Try getting a new bulb.

 

[wbrian63]

1 new bulb = 1 reliable lamp. On close examination, there are small glass shards inside the globe of the old bulb. That can't be a good thing...

 

[Random Guy]

1 new bulb = 1 reliable lamp. On close examination, there are small glass shards inside the globe of the old bulb. That can't be a good thing...

Arc tube may have ruptured. MH does that sometimes. Don't worry, it's perfectly safe. Luminaries are designed with possibility in mind, and are designed to safely contain an exploding lamp.