LOW-PRESSURE SODIUM LAMP LIGHTING DEVICE, TUNNEL LUMINAIRE AND ROAD LUMINAIRE

摘要

PROBLEM TO BE SOLVED: To maintain the high beam ratio after switching a power source at the time of interruption of service by providing an ordinary lighting device with an alternating current power source and a device for generating high frequency voltage with a direct current power source. ;SOLUTION: In a tunnel luminaire and a road luminaire, a low-pressure sodium lamp 3 is lighted by an alternating current power source 5. When the service by the alternating current power source 5 is interrupted, a changeover device 6 detects this interruption, and operates so that a high frequency generating device 2 is instantly connected to the low-pressure sodium lamp 3. On the other hand, since an ordinary device is opened, the low-pressure sodium lamp 3 is continuously lighted at a high frequency. The high frequency generating device 2 generates the high frequency at 60kHz or more with a direct current power source 1 such as a battery for emergency, the low-pressure sodium lamp 3 is lighted by the high frequency lighting, maintaining the required beam. The high frequency generating device 2 maintains 90% or more of beam ratio in comparison with the time of ordinary lighting.;COPYRIGHT: (C)1997,JPO