Above pic is orginial photo of a Westinghouse OV-10, likely a 250 watt mercury, in Beverly Hills, CA.
The OV-10 was Westinghouse's smallest remote ballasted luminaire in their line up, the OV-20 being next, then the OV-35, then finally the flagship HMA-60. The OV-10 was designed to operate smaller mercury lamps, typically 100 watt through 250 watt. OV-10s were also made with an intergral ballast. The OV-10 shared the same glass refractor fittings as the OV-12 cobrahead, which is a totally unique design and will not fit other small luminaires, despite that most small luminaires have glass that will fit each other. The OV-10 with intergral ballast continued in production until around 1962 or 63, when the OV-12 replaced it. The remote ballasted one likely remained in production until around 1965. A number of remote ballasted OV-10s are still in service in California, some in Beverly Hills, and some in Sacramento.
Close up of one of the OV-10s on the historic I-Street Bridge over the Sacramento River on the line between Sacramento and West Sacramento.
The exposed (top missing from box) oatmeal box shaped remote ballast, powering the above OV-10!
