7. Alarm System

TypeSpecification

Installation systemMaintenance & Failure

Detection

Calling SystemThis system is used to get attention from an

individu about some condition that may occur.

i.e. Indicator bell ring calling systemThe push button indicator normally placed at

a wall near to the door.The assemble of the cct should be neat &

tidy. To avoid humidity from interrupt the cct operation.

The indicator bell ring normally placed at the place that easy is to be seen.

Indicator lamp without bell calling system .

- hospital- Noisy place

Time indicator bell ring calling system- Factory- School – upgrade with time

centralized switch.

Alarm system.

Alarm System

Definition : a device that signals the occurrence of some undesirable event

Include in Call System category because this system alert a person to aware to something.

There is 2 type of alarm system :

i. Closed cct ii.Open cct

In a closed-circuit system, the electric circuit is closed when the door is shut. This means that as long as the door is closed, electricity can flow from one end of the circuit to the other. But if somebody opens the door, the circuit is opened, and electricity can't flow. This triggers an alarm.

In an open-circuit system, opening the door closes the circuit, so electricity begins to flow. In this system, the alarm is triggered when the circuit is completed

Closed circuits are normally a better choice than open circuits because an intruder can deactivate the open circuit by simply cutting the connected wires.

Open circuit System

Closed circuit System

Latihan

a. Give the definition of alarm system.

b. State 4 type of calling system.

Types of Fire Alarm System

1. Bimetal Strip Heat Detector When the bimetal strip detact the heat, it will bend up until connect the terminal & complete the circuit.

2. Heat Detector Air Type When the heat developed surrounding the air vessel, the air will heat up. The hot air will expand & push the diaphragm up.

Exercise

a. Give the definition of alarm system.

b. State 4 type of calling system.

Variety type of alarm

• One stroke (Satu lejang) alarm ringing in a time even the button is push more than one time.

• This alarm is use in the bus.

Types of operation in Alarm System

•Photo cell alarm system –

when a complete cycle of optical light is cut-off, the alarm will on.

•Security observation system – avoid security guard mutate to be a snake.

•Lighting calling system – Hospital.

Fire Alarm System

Fire Prevention SystemFire alarm system consist of push button that is assemble in parallel.

When the push button is pressed, emergency ring will operate.

PENGGERA KEBAKARAN DAN PENGAGIHAN SATU FASA

Fire alarm system is used to prevent fire and a system which will tell to the public if fire occurs.

If any below devices operates, signal will be send to Fire Alarm Panel.

1. smoke detector – to detect smoke2. heat detector – to detect heat3. break glass

Then Alarm Bell will sound and Mimic Diagram which located in the Fire Alarm

Panel will tell the location of fire or damages.

There were 3 types of common fire alarm panel that are currently used.

1.Conventional2.Semi-Conventional Semi-Addressable

3.Addressable

Fire Alaram Conventional Fire Alarm Semi-Conventional Semi-Addressable

Fire Alarm AddressableLoceng Penggera

Block DiagramFIRE ALARM SYSTEM

A.C. Voltage

Fireman

Switch &

Control Cct

RelayAlarm

CctAlarm Bell

Fungsi Setiap Blok

Voltan A.U - Supply power to the alarm cct. Suis Bomba - Emergency switch @ fire switch. Operate manually. Litar Kawalan - Contain smoke control device and temperature.Relay - Have the energy to attract contactor and complete warning circuit and make a bell sound.Litar Amaran - Function to produce revenue alarm bell ring

Gambarajah Skematik Penggera Kebakaran

3 types of failure

1.Sambungan kabel longgar.

2.Bateri ‘standby’ habis.

3.Pengesan kebakaran rosak

CARA-CARA UNTUK MENGATASI KEROSAKAN YANG BIASA BERLAKU

1.Pastikan sambungan yang dibuat pada terminal ketat dan kemas.

2.Pastikan bateri ‘standby’ diperiksa selalu.

3.Pastikan pengesan kebakaran dipasang pada tempat yang selamat.