Metal Halide Ballasts

[jm1470]

I do work on parking lot lights for a local shopping center, The lights are 1000 watt metal halide the voltage is 480. Lately I notice that the ballasts are burning up, I actually watch one catch on fire. I install fuseholders and fuses at the base of the pole to stop the ballasts from tripping the breaker. I am trying to figure out what causes this to happen. I have try different manufactures of ballast but have had the same results. Please help I am pulling my hair out on this one

 

[frenchelectrican]

Most common failure on 1 KW MH's is either burntout bulb which it can cause very high open circuit voltage or shortcircuited [ it do happend when the capaitors go bad it get very funky with it ] kamboom there go the ballast.

that why it pretty much SOP for me to install inline fuse for large parking lot luminaires [ this will also included large indoor luminaires as well ]

Merci, Marc

 

[cschmid]

that is interesting..I normally change out complete fixture when I have this problem..when you change ballast the insulation plates are disintegrating or have disintegrated. with out these pads the transformers never last..you can not buy the insulation pads and if you can I do not know where..I just change the whole fixture and problem gone..if not then you should start checking the wiring in the pole..it is cheaper in the long run just to change the fixture out, in my experience..

 

[frenchelectrican]

True but sometime it cheaper just swap the whole luminaire due the cost of ballast is not far from the cost of luminaire at all.

{ off topic but it related it very common to see the 1KW HPS do go bonker and smoked ballast pretty fast as well.}

Merci, Marc

P.S. a afterthought i know one of our member here he have a chart for the ballast open circuit voltage [ i am sure 480sparky will be more than happy to repost it here for ya ]

Merci, Marc

 

[captaincrab55]

Check for voltage drop. I was responsible for parking lot lighting at a Mall with 6,600 parking spaces and entrance roads.. Voltage drop and poor splices caused many failures. As the voltage drop problems were resolved, the failures decreased.