The ballasts I was using were Sylvania's. So it seems to be an issue with the technology. I don't know if the breakers tripped or not. It wasn't my facility and I answered basic lighting questions. I do know the fixtures were new(ish), not more than a couple months old.
It was the ballasts. Completely and totally "non-passively failed." I don't know if it was 120 or 277 but I know it wasn't 480v.
I don't know if I would be so quick to blame the pulse start technology, I have installed hundreds of pulse start fixture over the years and with the exception of a few brands and faulty designs I have very few failures, there are many faulty installation practices that can cause a ballast or lamp to fail, one of the biggest problems I find is no one pays attention to voltage drop, voltage drop is a big problem with HID fixtures, mercury ballast were very forgiving and it didn't bother them much, the same could be said about series ballast HPS, CWA ballast are a whole different story as they will try to maintain a constant current to the lamp and if there is a voltage drop it can and any times does destroy the ballast, also startup time is longer and this adds to the fixture running in start up mode longer which also causes premature lamp failure.
A couple years ago I had an apartment complex that was loosing lamps and ballast on a monthly bases, after checking the circuit voltage with the fixtures in start up mode I realized it was a voltage drop problem, the fixture was fed with 12/2 from the timers and contractors on 120 volt, I rewired them to 240 volts remarking the white neutral with black tape and it cut the current in half, some of these runs were over 200' never got a call back from them for this problem.
Another problem is heat, many manufactures place the lamp in the same compartment as the ballast, and the igniter, one of the reasons I use RUUD's wall packs they have three separated compartments with air space between this keeps the lamp heat away from the ballast and components, not to mention that there mounting method is second to none as it allows you to hang the fixture then wire it up while other brands you have to sit there and hold the fixture while wiring it up which can be a pain if on a extension ladder, another problem with the heat is many of these newer electronic ballast do not like it and fail, you mentioned that the ones you had a problem with were Sylvania's, the only MH ballast from Sylvania I have seen were electronic compact-ballast for ceramic MH lamps in cans, these did have a big problem with the heat when someone mounted them in an insulated ceiling, they were never made for being in an insulated ceiling same as the CFL type cans, even with an 2" thick x 2' insulated box around them they would over heat and fail, universal ballast did develop a 90? C ballast that did allot better and was the only fix I could come up with for a trucking company with a 28' high ceiling over the operations area done by a lighting company, this same trucking company has 320 watt RUDD wall packs all the way around it and I have only replaced 2 lamps in 6 years and 0 ballast, this is the kind of results I have been used to on lighting systems I have installed, I'm not saying there are problems out there but once you recognize the problems you will know what to look out for and know what the solution is to eliminate the failures, whether it is sticking with certain brands to making sure you wont have voltage drop problems to watching out for fixtures that put allot of heat on the ballast.
Here are a couple links that can be a good read about the development of MH technology
Venture Lighting
I made a mistake in post 2 as Luma is who I use for T-5 lamps and ballast Venture is a division of Advance and the owner came from GE lighting who holds many patents on MH development and designs and metal halide is all they do.
National Research Lighting Center
Be sure to click on the next arrow at the bottom of each page to read the whole publication
I'll also try to dig up a trouble shooting PDF file I have from Advance that repeats much of what I have said above as what causes failures, once you understand what causes the problems you will like the results that pulse start MH can give you to offer to your customers. I have many customers that now swear by them and are great repeat customers because of the performance of pulse start technology if installed correctly<<< thats the big IF, Oh there is one fixture I don't like, it is the 100 watt PS-MH inground flood that many use to light up flag poles, two problems with them, water infiltration and heat buildup on the ballast, they do have a high failure rate problems, even if they do look great
Ok book ended:lol:
