High Pressure Sodium Problem

[stevee]

I've installed 12 HPS fixtures. They are fed from a 3-ph, 4-wire, 120/208v system. I've connected them on three circuits sharing a common neutral. There are 4 fixtures installed on each circuit and are connected at 120v.

When I turn the lights on, all 12 fixtures individually cycle on and off. They don't all cycle on/off at the same time, they cycle randomly.

The fixtures are all new, I don't think I've got 12 bad fixtures so I'm sure it's not the ballast and/or lamps.

Any help would be appreciated.

Thanks!

 

[Cow]

Have you checked voltage at the ballast?

 

[K8MHZ]

First I would check to make sure that the correct bulbs were installed.

Then I would check the voltage at the ballasts to make sure it was within spec.

And what about ambient heat? Is it so hot where the lights are that an internal thermal protection device may be tripping?

What happens if you remove two of the hots so that only one phase is working? If the lights stop cycling you may have an issue with either the neutral being shared or some voodoo harmonics.

Or, you may have an entire batch of either bad bulbs or bad ballasts. Where were they made?

 

[K8MHZ]

The fixtures are all new, I don't think I've got 12 bad fixtures so I'm sure it's not the ballast and/or lamps.

Rule number 7 in Marky's Book of Troubleshooting:

Never EVER assume that because something is new it can't be bad.

I have spent enough time in manufacturing to know that hundreds, if not thousands of any man made devices can make it to the final user before a flaw is noticed. I was in QC many years ago and the company I worked for got a bad batch of material for window shades and around 3 million very expensive white window shades turned pink. They didn't turn pink right away. It took about three weeks. The amount of returns was so huge they had to rent space in a warehouse to store them.

 

[jwnelson1]

If I am reading your post correctly, you have 3 circuits sharing 1 netural feeding 12 HPS fixtures. You could have a loose or "floating" netural. I would have ran a netural for each circuit from the panel. I agree with K8MHZ. Never rule out a bad product even if it is new. Thourough troubleshooting will provide you with an anwser.

 

[broadgage]

Bad fixtures or bulbs are possible, but first I would check the voltage at each fixture. What wattage fixtures, how long is the circuit, what size is the wire, could be excesive voltage drop.
Check the ballasts are 120 volt, or if multi voltage that they are set to 120 volts.
Someone might have fitted 208 volts ballasts which would be fine if used line to line on a 120/208 volt system, but for line to neutral they need to be 120 volts.

 

[RichB]

+1 broadgage--was thinking that the ballasts were wired wrong--208(240) instead of 120

 

[yankj]

Are they controlled by photo cells? Are they wired correctly?