| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an emergency lighting device that diverts a lighting device of a low-power-factor type, to satisfy Class C of the guidelines for harmonics suppression. SOLUTION: This fixture is provided with a first low-power-factor lighting device, that illuminates a light source by commercial AC power source; a power- failure detecting means that determines the conducting state of the AC power source; a second lighting device that lights the same or a different light source with or from the energizing time of the AC power source by an emergency DC power source, when the AC power source fails; and an emergency lighting device that has a change-over means that changes over the first and second lighting device on the detection of a power failure. Between this emergency lighting device and the AC power source, a filter consisting of an inductor and a capacitor is provided. The values of the inductance and capacitance are set, in such a way that the upper limit of the resonance frequency of the filter satisfies Class C of the guidelines of the harmonics suppression and that the lower limit is set to a frequency that makes the output voltage of the filter become 120% or lower with respect to its input voltage.</p> |
