High pressure sodium lights

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Today I was sent to find out why 6 - 150W high pressure sodium outdoor fixtures were not comming on at night. The 6 lights are controlled by a photo cell. When I found that the light with the photo cell mounted on it didnt have any power I went to the breaker that fed the 120V/20A circuit that fed the lights. The breaker would not reset so I replaced it with a new one. I taped off the photo cell and got 5 of the six lights to come on. With just 5 lights on the circuit starts out drawing 25 amps and then slowlly falls down to 17 amps. Shouldnt the load be 150W X 6 = 900W / 120V = 7.5amps? These lights are the only thing on the circuit so why are they drawing so many amps?
Another problem I had was that the light that didnt come on needed a new ballast. Inside the light fixture is just a ballast. There isnt a capacitor or ignitor. At the supply house they sold me a "kit" which had a cap. and an ignitor. along with the ballast. The ballast obviouslly didnt work. When I went back to the supply house and showed them the part # of the Advance ballast I needed they claimed they were not made anymore. The lights on the building are only 2 years old. So why doesnt this light use a cap. or ignitor? Are these not required for a high pressure sodium fixture? Thanks for any help.
 
Re: High pressure sodium lights

Sorry, you can't use the lamp wattage to figure load. You will have to look at the nameplates of the ballasts and ignore the lamp sizes. If the current draw is going up, they are probably reactor type ballasts and will draw close to 200% of the expected current when compared to the lamps.

They are no different than fluorescent lamps where you can't go be the lamp wattage. :D
 
Re: High pressure sodium lights

Welcome to the world of "no wonder it cost less to purchase".

Advance does make a reactor style 150W 120V HPS ballast that has an integral ignitor. This ballast is listed as normal power factor so it does not have a capacitor. While the input watts are 170W, the maximum starting current is a whopping 4.5A. It looks like you can buy an optional capacitor (55mfd) to improve the power factor and lower the maximum current to 2.4A.
 
Re: High pressure sodium lights

You could try an HID breaker, it may hold better on inrush. But its your ballast type that is giving you the problem. You'll want to look at the mfgs catalog and get a fixture that does not have starting current more than operating current. Typically street lighting uses mag regulator ballasts, no inrush.
 
Re: High pressure sodium lights

Thank you very much for all the replys. So is it correct to say that no H.I.D. light bulb has a built in capacitor or ignitor? A guy at 1 supply house said they make a bulb with a built in ignitor and the guy at the other supply house said there is no such thing. Im confused. Anyone know who is right? Thanks, Brian.
 
Re: High pressure sodium lights

I am a member of the Illumination Engineering Society and on the Roadway Lighting Committee. I keep up with roadway lighting from both the utility side and NEC side. The utilities mostly use a mag-regulator ballast, there may be a lamp with a built in ignitor, but it would not be standard and have little use. In fact NEMA is developing a standard for ignitors so they will be interchangeable.
You would be best off time and money wise to install a quality HPS or HID fixture. Rabb makes some nice cost effective fixtures.
 
Re: High pressure sodium lights

I have worked for a city owned electrical system and my previous supervisor bought 12 bulbs that you could take out all internal parts of a HPS light except the ballast and this lamp would burn. I have since taken over the system and went back to Merc Vapor lighting due to the fact that I thing they are more forgiving. I think I still have 11 of the 12 bulbs. Point is they do make them.

Barry
 
Re: High pressure sodium lights

There are many HID ballast/lamp combinations.

Generally, ignitors are used with the newer "pulse-start" lamps that do not have starting electrodes, while the older lamps did not have ignitors.

Some details here-ECM article

Ed
 
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