New installed Metal Halide lamps getting busted and looking weird

[Mahdi]

Hi,

i have just installed new Metal Halide lamps on old fixtures in a soccer field, the color illuminating from some of the lamps was greenish, i checked the ballast and ignitor they were very old and in a bad condition so i replaced them and the Metal Halide lamp worked fine.

Other newly installed lamps after one day stopped working and the glass didn't break, but looked like the below photos. i decided to replace all ballast and ignitors and install another brand of lamps, and everything seems to be normal for the time being.

My question is, what could cause the glass of a Metal Halide lamp to bend inwards?

Thanks,

 

[don_resqcapt19]

That is typically from excessive heat. The glass got hot enough for the glass to get soft and "flow".

 

[hillbilly1]

Since you have an igniter, these are pulse start MH?

 

[gadfly56]

That is typically from excessive heat. The glass got hot enough for the glass to get soft and "flow".

I know quartz lamps for theater fixtures will fail if improperly handled. If you get a fingerprint on the glass, it will create a hot spot during operation and the envelope will fail there. I always cleaned the glass with IPA after installing them to keep that from happening.

 

[don_resqcapt19]

I know quartz lamps for theater fixtures will fail if improperly handled. If you get a fingerprint on the glass, it will create a hot spot during operation and the envelope will fail there. I always cleaned the glass with IPA after installing them to keep that from happening.

They will also expand a lot if you operate a base down lamp, in a base up position with some stage lighting equipment. Learned that in high school. Did not have an real guidance and installed the light upside down. The OD was about twice what it should be when I took them down after the play.

 

[gadfly56]

They will also expand a lot if you operate a base down lamp, in a base up position with some stage lighting equipment. Learned that in high school. Did not have an real guidance and installed the light upside down. The OD was about twice what it should be when I took them down after the play.

Where they the old 1,000w mogul base 9x16's (10x20?)? Never had that happen to me, but I rarely worked with luminaires above 500 watts, all small community theaters.

 

[Joe.B]

Since you have an igniter, these are pulse start MH?

I kind of wondered if something was wrong there too. I thought ignitors were only used for HPS bulbs?

 

[don_resqcapt19]

Where they the old 1,000w mogul base 9x16's (10x20?)? Never had that happen to me, but I rarely worked with luminaires above 500 watts, all small community theaters.

I think they were 500 or 750 watt, and as I recall a bayonet or bi-pin base. Too long ago to remember those details.

 

[Mahdi]

Since you have an igniter, these are pulse start MH?

Yes they are.

 

[Mahdi]

That is typically from excessive heat. The glass got hot enough for the glass to get soft and "flow".

So the cause of excessive heat is the old ballasts right ?
The stamped date on the ballast is 2009, i think it was time to replace them.

 

[hillbilly1]

I kind of wondered if something was wrong there too. I thought ignitors were only used for HPS bulbs?

Pulse start MH use starters, but regular MH do not. The lamp will have”PS” in the part number, if the fixture is PS from the factory, a regular MH lamp will not make contact with the center terminal, if the fixture was retrofitted, that may be the issue, a regular MH lamp instead of a PS lamp was installed.

 

[Joe.B]

Pulse start MH use starters, but regular MH do not. The lamp will have”PS” in the part number, if the fixture is PS from the factory, a regular MH lamp will not make contact with the center terminal, if the fixture was retrofitted, that may be the issue, a regular MH lamp instead of a PS lamp was installed.

Ah, thank you. Good to know.

 

[Little Bill]

Pulse start MH use starters, but regular MH do not. The lamp will have”PS” in the part number, if the fixture is PS from the factory, a regular MH lamp will not make contact with the center terminal, if the fixture was retrofitted, that may be the issue, a regular MH lamp instead of a PS lamp was installed.

The other type is called "probe" start, never heard it called "regular".

 

[hillbilly1]

The other type is called "probe" start, never heard it called "regular".

Pulse start MH hasn’t been around as long. The restrike time is much quicker with the pulse start.

 

[Flicker Index]

They're picky about how they're operated. Seeing where the thread starter is from, the unusual envelope is not a standard US size lamp.

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