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Design And Construction Of Fire Alarm System In A Two Storey Building
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1.7 DESIGN OF THE SYSTEM (DESIGN PROCEDURE)
In the
design of this circuit, much care was taken to ensure correct polarity
which in effect determines the continuity of the circuit. This was also
made possible by numbering each connections.
Nevertheless, the
approach to the design of this system involve trial and error methods.
After the initial design was completed, the model was set up to task the
behaviour of the initial system configuration and was by no means
satisfactory, and was re-designed and corresponding analysis completed.
This
process of design and analysis was repeated until a satisfactory
workable system was obtained. Then a prototype physical system was
constructed, built and tested to see whether or not it is satisfactory.
1.8 LAYOUT FOR THE CONSTRUCTION
The
layout for this construction is based on the inter-connection of the
circuit components of fig. 1.1 to achieve the desired function.
From fig 1.1, the switch unit comprises of the main switch S
The
control cabinet is made of polished plywood. Wires are connected from
the contactors to the connector. The connector terminals have been
numbered for easy and correct connection between the control
cabinet/display cabinet and the house. The control cabinet consists of
three (3) contactors each controlling each floor. The siren (horn) is
connected from a loop on the three contactors so that whichever
contactors that is energized, the siren together with the bell of the
particular floor must be on.
Also, from fig 1.1, it is seen that the
supply from the A.C mains is connected to terminals 1 and 4 of the
connector wires. The wires from the A.C source is connected to the
contactors and the three contactors connected in parallel.
The
cabinet contains the detectors switches which are connected in parallel
for each floor. Their connections are brought out to the connectors
according to their numbers.
The bell and the bulb on the control
cabinet are connected in parallel, each being connected to the connector
number outside it. The detectors and test bottoms on the cabinet are
connected in parallel and each connection brought out losing the
flexible wire to the connector number.
The connector serves the
purpose of disconnecting the switch unit from the rest of the building
and also for correct and easy connection between the control cabinet and
the house cabinet.
DIAGRAM
DIAGRAM
DIAGRAM
CHAPTER ONE -- [Total Page(s) 4]
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