Page 338 - Electrician - TT (Volume 1)

ELECTRICIAN - CITS

Small metal bracket type reflectors luminary or regular 25 or 40 watt tubular lamps effectively illuminate small
vertical display racks, stands and cabinets. (Fig 2)

Fig 1 Fig 2

Small compact lens posts available in both 250 and 400 watt size, mounted on columns or ceiling brackets, give
sales emphasis to small counter or table displays. Adjustable in spot size for 12 to 48 inches diameter spot at
10 ft. a 250 watt unit at 10 ft. will deliver 200 to 250 feet candles, with a 12 to 15 inches spot size: the 400 watt
unit will give 350 to 400 foot candles. (Fig 3)
For extended vertical surface displays - rungs, tapestries, draperies, paintings - a series of 150 or 200 watt lens
plate units at the ceiling is suitable for fixed display locations. Bracket type parabolic, polished metal troughs
produce equivalent results and have some advantage in greater mobility. (Fig 4)

Fig 3 Fig 4

For necessity and impulse items such as groceries, where attention rather than critical seeing is the requirement,
less engineering refinement is needed in shelf lighting equipment. Concentrating trough reflectors which
incorporate luminous panels for changeable advertising copy are satisfactory. Sockets 30 cms apart may be
fitted with 40 to 100 watt lamps, as conditions dictate. (Fig 5)
For lighting displays on columns or built-in shelving a metal nosing along the front edge of each shelf effectively
conceals small 25 watt tubular lamps as shown in the sketch. Lamps should be spaced not more than 30 cms
apart. Lumiline lamps are, of course, equally suitable in many cases.
Displays of glassware and bottled goods are highly attractive and colourful if lighted by transmitted light as
shown in Fig 5. An opal glass panel, illuminated uniformly from behind the lamps spaced not more than 1½ times
their distance at the back of the glass will provide a suitable luminous background.
Circline tubes used for window show case: For circline tubes the ballasts are specially designed and are easily
adaptable to assembly on the stem of portable lamps and in shallow wall and ceiling fixtures, and in some designs
they can be mounted within the circle of the tube.

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CITS : Power - Electrician & Wireman - Lesson 54-59