Скачать или смотреть Philips 180w SOX (low pressure sodium) lamp.

Start and run of a Philips 180w SOX lamp on a Philips L4135 leak transformer ballast.
The lamp is running in a remote-geared Philips MA60 / SRS201 road lantern that was (and still is, in some places) the mainstay of main road and motorway lighting in the UK.

The reason why is starts red and then slowly turns yellow is because when cold, the sodium metal is solid so a starting gas mixture of neon and argon is needed to heat and vaporise the sodium so it joins the discharge mix. As you can see from the video, this take over 10 minutes!

Low pressure sodium vapour lamps are the most efficient light source available (206 lumens per watt in some cases!) but they are rapidly loosing ground to High pressure sodium and Metal halide technology because of the none existent colour rendering properties and also due to the sheer bulk of the lamps themselves that require big and bulky luminaires.

Philips SOX 180W BY22d T65 1SL.
BY22d cap.
66 x 1120mm.
32,000 lumens (175 lm/w).
780ma arc current.
240v arc voltage.
18,000 hours to 50% failure.