Indoor Electronic Dimming Ballast Performance Reliability Study

An indoor (unconditioned warehouse space) performance, energy savings, and reliability study of electronic dimmable metal halide (EDB)(CMH and psmh) ballasts. Laboratory testing of a matrix of lamp manufacturers/sizes and ballasts. Data on photo metrics, energy savings and detected failures for work paper development.

Southern California Edison’s (SCE) Emerging Technology Program assesses products that have the potential to reduce electric energy use. One class of emerging technology is electronic dimming ballasts (EDB) for pulse-start metal halide (PSMH) lamps. The purpose of this project is to evaluate the robustness, performance characteristics, and the potential energy savings attributable to EDB for PSMH lamps. In December 2008, a set of sixteen electronic dimming ballasts - four each from four prominent manufacturers – began extended stress testing at the California Lighting Technology Center (CLTC) in Davis, CA. The ballasts, fitted with 320 W PSMH lamps, underwent continuous power cycling for over two months. Three of the four ballasts from each manufacturer underwent cycles of 5-minutes off, 15-minutes at full power, and 5-minutes at 50% power. The remaining ballast from each manufacturer was cycled on for eight minutes, and off for five minutes. This testing continued with minimal interruption for ten weeks until late February, 2009. In early 2009, power and photometric measurements were performed at the CLTC on a sample of ten EDB/PSMH combinations (two each from five manufacturers), and four magnetic ballast/PSMH combinations. At full power, the EDB/PSMH ballast/lamps achieved 4.3% more light output and required 2.7% less power than magnetic ballasts equipped with similar PSMH lamps. The correlated color temperatures (CCT) and color rendering indices (CRI) were nearly identical for the two ballast types. In addition to the aforementioned photometric measurements, the dimming response of the EDB/PSMH ballasts/lamps was tested. The EDB/PSMH ballasts/lamps were ramped up from dimmed operation to full-power. The five EDB/PSMH combinations started at an average of 30% of maximum light output in a dimmed mode, and ramped up to full power. The lamps/ballasts achieved 80% of maximum light output in 9 seconds, and over 90% of maximum light output in 12 seconds. The response time for PSMH lamps with magnetic ballasts is four times longer1. The fast response time of the EDB/PSMH ballast/lamp combination makes them suitable for daylighting and for some occupancy-sensor control applications where reaction-time is not critical.