OSRAM DULUX F - Manual (Page 53)

Economical long-life light sources with plug-in bases
Compact Fluorescent Lamps OSRAM DULUX ®
Technical Guide
51
3.3 Operating on dc sources
Compact fluorescent lamps cannot be operated from DC sources with conventional control gear.
Most ECGs are DC-compatible. The DC voltage must be around the rated mains voltage of 230 V.
See information supplied by ECG manufacturers.
Changeover units (emergency luminaires with internal changeovers, known as battery packs) are
offered. These feed the lamps directly on emergency power supply and interrupt the system circuit
between the CCG or ECG and the lamps. These changeover units for emergency lighting must
reliably comply with the parameters for preheating and for operating the lamps. If operated continu-
ously, control gear for emergency lighting can generate a DC component that may damage the lamp
electrodes (underload operation of the lamps). This underload operation with a DC component
causes electrophoresis in the lamp. As a result, the mercury migrates from one electrode to another
if the lamp is operated continuously, which causes one end of the lamp to turn red. This greatly
reduces the life of the lamp. In this case, OSRAM therefore cannot guarantee the life of the lamp.
Another factor with negative effect on lamp life in emergency operation mode, is often a higher
current crest factor, and also due to a insufficient energy supply of the emergency unit, a cold start
of the lamp.