SODIUM LAMPS
High pressure sodium lamps are discharge lamps, in which the light source is an arc tube containing sodium metal and neon gas as the ignition medium. Under the influence of heat, caused by discharges in neon, the sodium turns into steam and takes over the discharge. The sodium vapor emits an almost monochromatic yellow-orange light in length 590 nm. Sodium lamps are characterized by a very high luminous efficiency, exceeding 100 lm/W. In the light of sodium lamps, visual acuity in dust and fog increases, hence they are a very good source for illuminating communication arteries. The service life of high pressure sodium lamps is 12000 h. The ratings for high pressure sodium lamps are given in the table.
Board. High pressure sodium lamps ratings.
| Power
[W] |
Maximum starting current
[A] |
Lamp type | |||
| SON | ITS-PLUS | ||||
| Luminous flux [lm] | Total power [W] | Luminous flux [Im] | Total power [W] | ||
| 50 | 1,08 | 3500 | 59,5 | – | – |
| 70 | 1,35 | 5600 | 80,5 | – | – |
| 100 | 1,7 | – | – | 10000 | 114 |
| 150 | 2,4 | 14500 | 169 | 16000 | 171 |
| 250 | 4,5 | 27000 | 276 | 30500 | 286 |
| 400 | 6,5 | 48000 | 431 | 54000 | 431 |
| 1000 | 14,0 | 130000 | 1060 | – | – |
Low pressure sodium lamps are light sources with the highest luminous efficiency, reaching 200 lm/W. These lamps are used to illuminate highways and communication arteries.