Design of the fire warning is based on special calculations which promote the choice of the most effective ways of automatic prevention of the fires and also optimization of the expenses connected with mounting and service of the alarm system. Calculation of battery capacity of power supply is one of the main.
It is required to you
- - help tables of section of wires;
- - technical characteristics of fire annunciators;
- - technical documentation of the room equipped by the alarm system;
- - the existing standards.
Instruction
1. Decide on electric energy source which will feed the fire warning. Solar batteries, accumulators, thermogenerators and other elements can act as such sources. Get acquainted with technical characteristics of these elements because these data will be necessary for further calculations. In case the capacity of one source is not enough, the battery is formed of several accumulators, connected in parallel.
2. Specify values of tension at each energy source – it has to be identical. Otherwise the counterbalancing current will significantly reduce battery capacity. Battery voltage at serial connection is equal to the sum of tension in the separate energy sources making it.
3. Calculate extent of losses which are inevitable in the course of power transfer, having used the data provided in the existing standards. Competently to place fire annunciators, it is necessary to learn the section of wires. It is defined as ratio of the total power rating at the set tension to current intensity in electrical circuit.
4. Determine the necessary section of wires and voltage cables, having used summary help tables. Calculate possible losses of line voltage. In this case indicators of induced resistance of conductors and their intensive loading are not taken into account.
5. Following the approved techniques which are used at design of the fire warning, determine in the rated way necessary battery capacity for work in standby condition and in the alarm mode. Then determine the total capacity of energy source – by summation of the results received for waiting modes and alarm.