Z.5128 SC. Lantern with symmetric dome refractor and clear outer bowl. Sectional scale drawing. The iso-candle of an "OXFORD" lantern with an outer reflector is based on an average light output through life from a 500 watt vee filament OSRAM almp. (7,485 lumens). 300 w. 500 w. Directional intensity ratio 5.2 5.3 Light above horizontal 8% 8% Light output ratio 75% to 80%

SIDE ENTRY "OXFORD" & "WEMBLEY" LANTERNS Z.5128 SC. Lantern opened to show the general construction.

Side entry "Oxford" and "Wembley" Lantern.

Use Main road lighting; 25 ft. mounting height; spacing 120-150 ft; road width up to 40 ft.

Lamps Z5128SB "Oxford," Z.5128*C "Wembley", Z.5128*R "Wembley," and Z.8128"O" for use with a standard 300W or 500W OSRAM lamp.

Mounting Side entry. Requires not less than 3 in. of horizontal unthreaded 1¼in. gas barrel. When fully home two 7/16 in. Allen grub screws grip the barrel.

Lantern Body Totally enclosed die-cast light alloy. A spring fit detachable top of spun light alloy gives access to terminal block and focusing gear. A water baffle and drainage hole are provided to carry off any water runnign along the bracket. An earthing screw is provided.

Lampholder Porcelain G.E.S. mounted on a bridge piece and wired to a porcelain connector with heat-resisting wire.

Focusing A bridge piece carried on two vertical rods one marked with grooves indicating the correct focal position for the different lamp wattages.

Optical System
Wembley form. Three forms of light distribution are available, dependent upon the type of dome refractor in use:-
(1) Symmetric, giving all-round distribution Z.6504 (reference letter "S") dome refractor. (2) 160 deg. non-axial asymmetric, giving main light output up and down the street just away from the kerb with Z.6510 (reference letter "N") dome refractor. (3) Axial asymmetric, providing light output directly up and down the street with Z.6516 (reference letter "A") dome refractor.

*Note: It is necessary to quote the reference letter that identifies the light distribution required. See example below.

The dome refractor is held by three spring supports from a white enamelled inner reflector.

Outer glassware. Three forms of outer glassware are available, clear globe, Cat. No. Z.6467 (reference letter "C"), rimpled globe Cat. No. Z.6477 (reference letter "R") or stepped opal, Cat. No. Z.6468 (reference letter "O"). The last form is purely diffusive and no dome refractor is supplied; the lantern Cat. No. being Z.8128"O".

Oxford form. When used as an "Oxford" lantern the optical system consists of a symmetric dome refractor and an outer bowl refractor (reference letter "B") Cat. No. Z.6610.

Examination of the iso-candle diagrams on pages 6 (here) and 1 will show the difference between the light distribution of a "Wembley" and an "Oxford" lantern.

Weathering Finish The light alloy is espcially selected for its resistance to corrosion. Further protection is obtained by the use of a suitable primer, undercoat and matt aluminium top coat.

Erection Instructions Full erection and focusing instructions are packed with each lantern.

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