Willis Lamm's Traffic Signal Collection (And Street Lights Too) Clicking on a picture will bring up a larger view in a new window.   General Electric (GE) Form 175 Street Light

The Form 175 refractor is an upsized version of GE's Form 79CR. Instead of being bowl shaped like traditional gumballs, this refractor comes to a point. The refractor beads are designed to minimize light output to the sides and direct light efficiently and quite uniformly in a broad downward circle or in four directions for a corner mounted luminaire. These lights were often used to illuminate intersections and residential streets where it was desirable that most of the light be directed onto the pavement not shine towards nearby residences. The Form 175 was designed to provide higher intensity illumination than the smaller Form 79CR While there was a push to more energy efficient mercury vapor lighting, there still was a need for lower intensity lamps for smaller streets. Although Form 175 luminaires could use incandescent lamps, GE designed the fixture to utilize 175 watt mercury vapor lamps. The original Form 175s had remote ballasts. Later the "Power Pack" model was produced that had a bit more of a clam shell appearance and in which the ballast was located in the head. This particular luminaire is actually a pretty simple and effective design. (Although the original lamp was 175 watts, I'm using a 100 watt mercury vapor lamp for indoor display.)

Components of the Form 175 Luminaire

The luminaire itself is fairly light weight. The slip fitter is cast but the rest of the body is a single piece of stamped aluminum. The socket mounts next to the slip fitter and the refractor opens with a latch and hinge.

Interior view. Slip fitter with anchor bolt and two leveling bolts.

Profile view. GE logo and pointer to align refractor with band screw.

Interior bottom of refractor with Holophane ID. This refractor would have been used on the corner of a 4-way intersection. Continue to Westinghouse AK-10 Street Light