Sodium Street lighting problem

[linsaband]

HI

Wonder if anybody can help with this problem, have car park with 12 sodium Phillips fittings on 15 ft poles. 2 circuits , 6 poles on each one running through contactors controlled by a photocell. Lamps go on and off at random as if they are cycling. If I switch off 1 circuit the remaining one still cycles. Have linked out the photocell with no difference and the voltage in and out of each contactor is constant. Phillips technical have been no help, wondered if anyone has come across anything similer before I start going any deeper! Has only started since cold weather snap if that is significant.
Cheers

 

[Marvo]

I'm guessing they're high pressure sodium, LPS generally don't cycle, they just don't ignite. I think with sodium it's the other way around with the cold weather thing, they generally start to flash when they have warmed up, when the lamp cools it often re-ignites as the voltage required to strike an arc is then lower.

I would try replacing one lamp and see if it stops the cycling. Cycling is an indication of HPS end of life.

 

[UNG]

When you say the lamps go on and off at random is this all the lamps on one circuit at the same time or each lamp randomly going off

If it is each lamp randomly going off then I would suspect you have the wrong fitting / lamp combination if the fittings have ignitors in them you need to make sure that the lamps do not have an internal ignitor, the lamps are normally marked with an I or an E in a triangle for internal or external ignitor. I think you may need lamps with an external ignitor as it sounds like the fittings have an ignitor in them

What make / model of fittings / lamps are you using?

 

[Merl]

Hi linsaband,

Have you done any checks for volt drop on the incomming supply at each column/lamp head?
What size is the cable in each run and approximately how long are the runs?
Are the lamps SOX or SON lamps and do you know roughly how old they are? Internal or external ignitors (SON)?? The lamps have a lifespan of about 3-5 years dependant upon type.
Cycling is fairly common in SON lamps with internal ignitors when they're near the end of their life, but for all the lamps to be cycling at random may suggest a common problem on the supply side. Or, if all the lamps were fitted/replaced at the same time they may be near the end of their useful lifespan.

Do a bit more investigating if you can. Hope it's just somethig as simple as lamps for you though!

 

[linsaband]

Hi, thanks for the replies guys, installation has worked fine since hotel was built, about 5 years ago. My next step is checking at each pole but was asking initially because access is a problem due to height. Will get up there tomorrow and let you know exact lamp and fiiting models. I suspected a supply problem as it happens on both circuits even if one isolated and they are on seperate contactors but voltage is constant during fault. Different lamps go off randomly on either circuit I reckons lamps are nearing end of life but this problem only started 3 days ago and affects all lamps so unlikely this is it. Temp was was down to -12 here before fault appeared wondered if this could be a factor. I will post findings tomorow night, thanks again

 

[accordfire]

Sounds like end of life of a HPS lamp somewhere.

If access is an issue - i.e. difficult to arrange, then make the most of it by pushing for a re-lamp of all 12 now, and get your cleaning kit out too.

 

[davelerave]

it sounds like a temperature related issue-assuming supply voltage is ok

as lights on both circuits have suddenly starting giving trouble

 

[nickblake]

they are not on differant phases and some where there a dodgy neutral

 

[WDMDL]

20000 hours, at 12 hours a day would be 4.5 years.... so I'd take up accordfire's suggestion and do a clean-up and re-lamp of the lot.

Simon.

 

[mogga]

End of life lamps try relamp and burn up a couple