General Electric Urban and Highway Luminaires

   Form 109
   Form 400

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GE Form 109

This is probably the most popular mercury model in the late 1940's to mid 1950's. It accommodates up to 400 watt mercury lamps or 600 watt incandescent lamps.

This luminaire was advertised as having a then novel rectangular light distribution pattern contrasted with the round and oval patterns delivered by competing models.

Usually when I saw the incandescent style, it had a more upright cylindrical head, possibly a less expensive head from another vendor, and an adapter ring to fit the larger diameter reflector opening. Very rarely did I see the incandescent style with the same head (shown here) as the mercury style.

Wrinkles stamped into sides of reflector indicate the vintage of the fixture, with fewer wrinkles on the earlier fixtures. This specimen has two wrinkles. Others I have seen have up to five wrinkles.

This luminaire is sometimes called Form 109 Reverse, probably because the lamp socket is towards the front.

Weight of Form 109 luminaire: 21-1/4 lb.

The right photograph shows a Form 109 disassembled. The lamp and socket are shown in the position they would occupy inside the reflector assembly. The socket has a bracket with a small clamp that attaches to a stud just inside the front edge of the reflector opening (top edge as shown).

The globe (reflector and refractor assembly) is attached to the head by a hinge at the front. For lamp replacement or cleaning it would be tilted forward and up somewhat as one takes off a shoe. The globe can also be lifted off after the lamp and socket are disengaged and left to dangle from the head (hopefully not for long).

The refractor is permanently attached to the reflector. How the metal edge is machine pressed into the groove around the perimeter of the refractor without frequent breakage during mass production escapes me. If the glass was broken during use, it is necessary to send the reflector back to the factory for refurbishment, or more likely the globe is discarded.

The dark vertical line seen through the reflector opening is the bottom edge of the refractor which has more or less of a "V" shape when the luminaire is viewed from the front.

The mercury arc shaping coil can be seen mounted diametrically crosswise in the head at the lower right of the view. The other item in the head is the terminal strip, which is recessed more than it appears to be. At first, the less expensive mercury lamps had to be mounted vertically, otherwise the mercury arc had a tendency to bow upwards and melt the glass bulb. The shaping coil forced the arc back into a straight across path. Later as "burn in any position" mercury lamps became more readily available and came down in price, the shaping coil was no longer needed and was disconnected but left in place.

To the left of the head is a reflector which covers the arc shaping coil. For the incandescent version, this reflector has a hole through which the vertically mounted lamp's base extends.

GE Form 400 (lower left)

This is probably GE's answer to the clamshell styles offered by Westinghouse, Line Material Industries, and others. It takes horizontally mounted mercury lamps up to 400 watts.

It was introduced in the mid 1950's

Has lightweight stamped sheet aluminum body, contrasted with Westinghouse's changing from a stamped body to a cast aluminum body. Has inner reflector (double wall) construction. The refractor is held in a cast aluminum perimeter ring with a split held together by a screw.

This was the beginning of the trend to a tilted out design that directs more light into the street and less light into bedroom windows.

Form 400's were available with photocontrol mounted on neck, and also (very rarely seen today) with a ballast mounted in an enlarged neck chamber, as a forerunner to today's cobra head style luminaires.