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BULB DISCUSSION BOARDS => Modern Electric Lighting => Topic started by: mr_big on February 17, 2005, 03:46:52 pm

Title: melted electrode in mercury lamp
Post by: mr_big on February 17, 2005, 03:46:52 pm

OK I don't know how this happened but the starting electrode in my new Sylvania 1000 watt mercury lamp has melted I turned it on it ran for a few seconds and then the breaker blew any ideas on this one

Title: Re: melted electrode in mercury lamp
Post by: pSlawinski on February 17, 2005, 09:44:19 pm

1) Did you run this on a ballast?  (If your answer is NO then you killed it by over driving it)

2) If you did run this on a ballast how old is it?  Your ballast could be dead, and I would not suggest running any other lamps on it.

Title: Re: melted electrode in mercury lamp
Post by: mr_big on February 18, 2005, 11:14:15 am

I did run this on a ballast and the lamp is brand new
I have a fefw extra that are really heavily used but still start easily
I will have to try one of them to see if it happens

Title: Re: melted electrode in mercury lamp
Post by: pSlawinski on February 19, 2005, 09:37:21 pm

What condition is the ballast in?  How many devices are on the circuit you ran that lamp on?

Title: Re: melted electrode in mercury lamp
Post by: mr_big on February 23, 2005, 11:22:24 am

this is the only thing that I have on this circuit I don't think the ballast is bad because the other lamps that I ran on it worked fine
One of the lamps that I had a clear Sylvania 1000 watt mercury lamp did not work because it was heavily used and the arc tube was completly black it was because it was running in a fixture on a tree that was covered in ivy so I could not see the lamp
I have checked the wiring and voltage in my house and it is 120 wolts AC So I don't think it could be that

Title: Re: melted electrode in mercury lamp
Post by: pSlawinski on February 23, 2005, 11:52:26 am

The only thing I can think of that would cause the starting electrode to fail immediately would be a ballast failure.  As for your circuit breaker popping that could be from the ballast drawling more current after being turned on.  I have run my 1000W ballast on the same circuit as my computer, which is plugged into an uninterruptible power supply (UPS).  Immediately after plugging in the ballast the UPS beeps as if the power had been cut or there was a brown out.  If the circuit you run your ballast on is on a 10A breaker it is possible that the higher current drawl right after starting could be to blame for your breaker popping.  A 1000W ballast drawls ~8.333A during normal operation.  I'm not sure what the current drawl is during startup, but I believe it would be higher than 8.333A.

I guess you could also just have a bad lamp. Did you say the starting electrode was completely melted, or just slightly?  As far as I know Osram Sylvania mercury lamps are not particularly know for their quality...

Title: Re: melted electrode in mercury lamp
Post by: mr_big on February 23, 2005, 03:40:01 pm

the starting electrode was completly melted
I know about the breaker it was a new 20 amp breaker I just replaced my entire panel because my old one got ripped off the wall by a tree

Title: Re: melted electrode in mercury lamp
Post by: pSlawinski on February 23, 2005, 04:35:28 pm

Hmmm, can you get some pictures of the lamp and post them here?

Title: Re: melted electrode in mercury lamp
Post by: mr_big on February 24, 2005, 11:22:21 am

here are the pictures of the lamp the outer envelope has accidentaly broken

Title: Re: melted electrode in mercury lamp
Post by: James on February 24, 2005, 12:46:13 pm

I have seen something similar in 700W lamps recently supplied by Osram, two out of ten of them failed after 400 hours.  Osram transferred all mercury production to China last year and while most are excellent, I have seen problems with the higher wattage types.

Best regards,

James.