HPS Lamp or ballast

[conmgt]

How does one tell if a lamp is causing a problem or the ballast.
In particular, a parking lot HPS fixture is extinguishing for 2 mins and then relighting and staying lit for 30 min to 2 hrs and then extinguishing again and then relighting and so on.
I called a major ballast mfg. and the person who answered said "Put a new lamp in and if the problem remains...you need a new ballast" Ummmm gee thanks!

 

[Chenley]

Google's your friend: http://www.americanelectriclighting.com/Library/Literature/PDFs/HPS%20Servicing%20Guide.pdf

 

[Mr. Bill]

Sounds like end of lamp life. If this happens too long the ballast will fail too.
http://en.wikipedia.org/wiki/Sodium-vapor_lamp#End_of_life

 

[480sparky]

Advance Ballast's troubleshooting guide.

 

[conmgt]

Excellent references from both. The AEL servicing guide is fantastic. The Wiki was straight to the point. Thanks to both for your response

 

[conmgt]

That's a great one too! All the info one needs is out there.