250 watt MH

[mjf]

Have a 250w metal halide lamp that appears to "flicker" incredibly fast. It's in an outdoor wall pack and the area it's responsible for lighting is still well lit. Looking directly up at the fixture is when the flicker is noticable. Any ideas as to why this would be occurring?

thanks in advance

 

[480sparky]

Vibration of the lamp?

 

[mjf]

Vibration of the lamp?

I guess that's possible.

But

building is empty (at night)...no machinery, etc in building causing vibration
luminaire is securely secured to (secure) building
socket is properly secured to luminaire
Lamp is securely installed

checked all these items
(OK, I didn't attempt to move the building).

what would be causing this vibration?

any other thoughts or experiences with this type of circumstance?

 

[ron]

Can you touch the housing to see if it is vibrating?

 

[Festus20]

vibration of the lamp

 

[Cow]

I'd probably just replace lamp first, then the ballast too if the problem didn't go away. I'm assuming all wiring connections are tight and the voltage isn't fluctuating.

 

[tom baker]

Simple explanation is a bad lamp. Every now and then one will slip thru production, ever had a bolt with no threads? The lamp mfg process is automated, they make thousands,

But its an odd problem. Post back with what you find.

 

[mcclary's electrical]

The plates in the xfmr are loose and probably vibrating the filament. I've heard MH's on metal buildings that literally sound like an air chisel hitting the tin. Yours is probably vibrating just enough to shake filament

 

[mjf]

thanks for all the replies folks

I'll try to remember to post what I find when I get back over there.