The neat luminaire shown here is the flagship of Westinghouse's famed Silverliner line of cobrahead streetlights. The OV-50 was designed to operate large 700-1000 watt lamps, like the GE M-1000 and AE 327. Note a couple of interesting things about this luminaire:
The glaresheild (I like to call them lampshades) fits onto the existing luminaire and sheilds the refractor; cutting down on uplight and glare. This was done before the full cutoff luminaires became the craze. Glaresheilds were popular in California from the 1950s through the 1980s, especially at signalized intersections and on the freeways/interstates. They have become almost obsolete in favor of full cutoff luminaires, but existing luminaires with sheilds are still fairly common in CA.
The fin on the top of the lumianire. When I was a kid I thought the fins were photocontrols on the large luminaires, since PCs also go on top of the luminaires! Actually, the fins hold the capactiors, and with huge 700-1000 watt ballasts there is no way to cram everything in, so the fins were made for more room. Later OV-50s do not have the fins however, since the capactiors were moved to the doors.
This particular OV-50 shown is a 700 watt mercury vapor, and date to the early 1960s, and continues to be in service to this day, and is found in a town where mercury vapor streetlights are still in abundance.
