My question was based on a paper written about pulse vs probe start. One of the stated advantages of the pulse over the probe was you could use a 320W pulse start and get the same light output as a 400W probe start. Plus better efficiency.
I'm trying to get some facts together to present to a customer that would justify him spending more for me to change his fixtures to pulse start. I was going to just change each out when they need servicing. Not all at once, just when one needs a ballast kit.
320=400... that isn't always the case but it can be depending on what your comparing. Metal Halide lamps burned horizontally will have a lower lumens rating over vertical burns. A position dedicated probe start will have higher initial lumens as well as the pulse start counterparts than universal made burners. Type O lamps are always a bit lower than type E. If the right combination of lamps and conditions are paired the 320 will be brighter than a 400 but not in others. Marketing statistics are easy to manipulate. In your case what is the exact system being evaluated?
I tend to find that the light output of a universal burn probe is about that of a type E 350 watt vertical pulse start. But pulse starts have 3 major advantages even if initial lumens are the same as what they are replacing
1. pulse start lamps have much higher mean lumens. At 10,000 hours a 20,000 hr rated probe start lamp will literally halve in light out put. Literally. A PS lamp only declines about 20% if that. Halving often doesn't even occur until past the rated life. Usually by then the lamp just fails to light.
2. 3-5 minute restrike over a 30 minute.
3. Color stay uniform over the life. As MH lamps age they migrate toward a blue green others toward a bright pink. Most just end up looking similar to clear mercury vapor bulbs by the time 8,000 hours rolls around.
