Been re-wiring HPS fixtures today and noticed that the new ballast kits don't come with a resistor for the capacitor. The schematic still calls for one, I bench tested one anyway to see if the lamp would fire, it did. Then after warm up I disconnected the fixture, then re-energized to ensure that it would 're-strike'. All is fine.

I am left wondering just what purpose this resistor serves. I feel like I should already know the answer to this. Never the less, I just want to figure this out, humiliation or not.

The fixtures are 400watt Holophanes, the capacitors are 56uF with typical three wire starters and 480v ballasts.






Luke Clarke
Electrical Planner for TVA.