Originally Posted by Americangrower
Thanks for the info.. So you are saying no CMH can run off digital ballast and some can run off the old mag ballast? Don't Digi run at 50 to 60 hz? Sorry for the questions just trying to figure out if I can use Digi ballast. Would like to switch over but hate the idea of wasting 4 perfect ballast.
With mag ballasts, the input & output frequencies are the same & they're sinusoidal. The transformer just changes the voltage. Grower's electronic ballasts developed for HPS have sinusoidal high frequency output in the 100K range. Philips developed the 315 lamp & 100hz square wave electronic ballast as an entirely different specification, a new system. Other makers now offer lamps & ballasts conforming to that system.
CMH lamps were originally developed as high efficiency screw in replacements for commercial mag fixtures. Philips markets a whole line of CMH lamps for 250w, 400w & 1000w MH fixtures at 205w, 330w & 860w respectively. GE makes a CMH retrofit lamp for 400w HPS fixtures. None of them have the high efficiency of the 315 system.