Bottom view of a GE M-2 sodium vapor luminaire at the Golden Gate Bridge Museum.
Back in the 1930s, the same decade when the first low pressure sodium vapor lamp was developed by Philips in Europe, GE developed their own version of the low pressure sodium lamp. They came in several types, but the most common one for streetlighting was called the NA-9 lamp. At that time the high pressure sodium lamp didn't exist, so these lamps were just called "sodium vapor". GE also developed a strange looking luminaire with the winged reflector called the M-2, shown here. Both the Golden Gate Bridge and the San Francisco-Oakland Bay Bridge had thousands of GE M-2s from their opening days in the mid 1930s all the way until 1970, when they were replaced by HPS. The Golden Gate Bridge Authority kept one of the M-2s along with its NA-9 180 watt sodium lamp at the Golden Gate Bridge Museum so that everyone can see it. Special thanks to Marc Phillips for providing these vidcaps.
Close up of whole luminaire and lamp. The close up photos below show details of the NA lamp. Did you know that those old sodim vapor lamps took 30 minutes to warm up to full brightness?
