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Motorway Lanterns

Application
The lanterns are designed for Motorway lighting with mounting heights up to 12 meters and are also suitable for Group A1 installations.


Compliance
The lanterns comply in all respects with the requirements of B.S. 1788 and carry the British Standards Institution Kite Mark of approval.

The lanterns are acceptable to the Department of the Environment.


Lamps
Z9754 Cut-off lantern for 180 watt Super SOX lamp.
Z9752S Cut-off lantern for 135 watt Super SOX lamp.


Lantern Construction
The body of the lantern is made from an aluminium extruded section with die-cast ends secured by continuous welding. The casting at the entry is a strong one-piece unit with an entry to accept a 1¼" BSP spigot 12.7 cm (5") long for the Z9754 lantern and a 1½" BSP spigot 17.8cm (7") long for the Z9752S lantern. The casting supports the weight of the gear through special mounting brackets.

The extruded section of the body is shaped to give continuous full length support of the reflectors forming the main component of the optical system. This means that the reflectors cannot be dislodged or deformed during maintenance or handling. The section also provides a substantial weathering lip and a fully protected recess for the gasket used to seal the bowl to the body. The alloy used for the extruded section is HE9.

The body is totally enclosed by a vacuum formed acrylic bowl seated on a pure wool tropicalised gasket. The bowl is hinged on one side by stainless steel hinges of a type that allows the bowl to be lifted off intentionally, but prevents it being knocked off accidentally. The opposite side is secured to the lantern body by substantial stainless steel spring loaded toggle catches.

A hinged partition makes a separate compartment for the lamp operating gear, fused terminal block, light cell socket and lamp holder. When the lantern bowl is in the open position for maintenance it is not possible to touch any part of the terminals or wiring. The cover to the gear compartment is hinged along one edge and secured by a s substaintial captive fastener on the inside edge. When this cover is in the open position there is clear access to all components and their connections, checking or replacement of any wiring or component is a quick and simple operation.

The inside of the body is finished in white enamel and the outside in hammer aluminium finish, both finishes are applied on their specified undercoats and stoved.


Optical System
The main optical components of the lantern are two brightened and anodised aluminium reflectors of curved section. The white enamelled diffusing top of the inside of the lantern provides a secondary optical component. Thus the optical system is substantial, simple and easily maintained.


Photo Electric Cell Control
The standard lanterns can be fitted with a G.E.C. Cirlok socket and G.E.C. ZWK 528A Witton Kramer photo-cell. The lanterns can be modified to take other types of photo-electric cell control units.


Lamp Operating Gear Fitted
Z9754: Z1634 transformer tapped 220/240 volts only, ZF8566 capacitor 14 mfd.
Z9752S: Z1630 transformer tapped 200/250 volts, Z1781XL capacitor 25 mfd.


Lantern Weight and Windage
Z9754
Weight: 21.75kg. 48 lbs
Windage (side elevation): 0.228 sq.m. 2.45 sq. ft.

Z9752S
Weight: 20.3kg. 44.5 lbs
Windage (side elevation): 0.186 sq.m. 2.00 sq. ft.




(1) Prinicple vertical polar curve through street axis.
(2) Principle conical polar curve.




Isocandela data shown are the mean of two sides and apply for a lamp of 1000 lumens output.




The Z9754 Motorway Lantern.




Photometric Data Lantern Data Z9754 Lantern Data Z9752S Requirements of BS1788 and CP1004
Lantern Design lumens 31,500 21,500
Light flux in lower hemisphere (lumens) 24,570 16,700 See CP1004 Tables 2-8
Downwards light output ratio 0.78 0.78 No limits specified
Angle of elevation of upper limit of beam 68° 68° 65° must be within beam
Angle of elevation of lower limit of beam 57° 57° 65° must be within beam
Peak intensity ratio 2.1 2.1 2.0 to 4.0
Maximum intensity ratio in the zone from 0° to 30° 1.56 1.56 0.3 to 2.0
Minimum intensity ratio in the zone from 0° to 30° 0.121 0.121 0.3 to 2.0
Maximum intensity ratio 0° to 30° Peak intensity ratio 0.74 0.74 0.8 maximum
Angle at which 1.2 intensity ratio occurs above the peak 74° 74° 72° to 78°
Intensity ratio at the horizontal 0.03 0.03 0.15 Maximum
Divergence of beam centre from the axis of the road in azimuth Zero Zero 15° Maximum