Page 335 - Electrician - TT (Volume 1)

ELECTRICIAN - CITS

Lighting for decoration - Serial set design - Flasher

Objectives: At the end of this lesson you shall be able to
• state the methods used for decoration
• state the names of flasher and their function.

Use of decoration lights
Electric light decoration for special occasions like wedding parties, festivals and fairs is a common feature
nowadays. Special electric light sign circuits add much colour, fun and pleasure on the occasion. Electric signs,
particularly neon signs, are extensively used in advertisements which have tremendous eye catching effects.
Decoration with electric signs improves the appearance of a building and makes the place more attractive.
Two methods are mainly used for decoration.
• Signs employing miniature low voltage incandescent lights which can be switched on and off in sequence to
produce the desired effect.
• Neon signs employing tubes shaped to produce designs in various colours, the colour being determined by
the type of gas used in the tube.
Miniature incandescent lamps: Miniature incandescent lamps are normally available with 6V, 9V, 12V & 16V
ratings with different colours which may be grouped in series or series parallel combinations for operation in
available 240V supply.
For getting different messages and decoration effects the following types of flasher signs are used.
Speller type flashers are used for spelling out signs letter by letter or word by word for building up or down, plain
on-off flashing, with changing colour.
Speed type flashers are used for operating spectacular signs such as lighting waving-flags, - flame, revolving
wheels etc.
Script type flashers as the name implies are used when the effect of handwriting in script letters is desired.

An example of a speed type flasher for revolving is shown in Fig 1. The speed of running light/ rotating light can be
adjusted. In this three-point running light (the sign flasher) there are three groups of lamps, each group switched
on and off, in sequence, for running effect (Fig 2) with the help of a small induction motor which is running on eddy
current principle and is connected to 240V/115V 50 Hz. Cans or drums are mounted on a shaft which is rotated
by the motor.
The circumference of the cans or the drums are so cut that the brushes will make contact only during the fixed
portion of the revolution, thus completing the circuit. We can make three independent circuits by the 3-point sign
flashers which are switched ‘ON’ and ‘OFF’ successively.

Fig 1 Fig 2

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