ELECTRIC BELL

Abstract

From time memorial, bells have been extensively used in telephones, doorbells, railroad crossing, school bells, burglar alarms, and alarms in industrial plants although in this contemporary days, they have been replaced with electric sounders. Furthermore, several objects around us contain electromagnets. Since the electromagnet is the working principle of the electric bell, it can be said that this electrical device works by converting electrical energy into mechanical or sound energy.

Introduction

The electrical bell is can be said to be a mechanical bell which operates by the means of an electromagnet. Normally, when an electric current is passed through it, it creates a repetitive ringing and buzzing sound (Avison, 1989). The following sketch shows the internal mechanism of an electric bell

From the above figure, an electric source powers or supplies electric current to the electromagnet which is the main component of the electric bell. The switch which is pressed so as to sound the electric bell majorly acts as the circuit breaker or just the completing the circuit.

Whenever the switch is pressed, the electrical circuit loop is complete which in turn causes current to flow via the circuit.  The arm which is used for sticking the gong is connected to a spring at one end with the iron ball at the other end (Avison, 1989). This is termed as a striker or clapper. During the flow of current when the circuit is complete, the arm is attached to an iron strip that is attracted to the electromagnet.

The main reason for this attraction is because the magnetic field that is created by the electromagnet ends up attracting the iron strip to it when the current is complete. Contrary to that, when it is at the resting position, the clapper or striker is held away from the gong on the account of the spring that is attached to its arm (Hasluck, 2011). This is said to be an anchored arm.

On the other hand, now that we have understood the essential parts in an electric bell, let’s now look at the precise functions of these basic components

1. a) Electromagnet_ after regaining its magnetism, it pulls the armature thus making the hammer to strike the gong again.
2. b) soft-iron armature_ once the electromagnet is magnetized and attracts the soft-iron armature, the soft-iron armature assists in pulling the hammer to strike the gong which is attached to it (Hasluck, 2011).
3. c) Hammer_ the hammer strikes the gong which is attached to it at one end.
4. d) Gong_ The gong which is in the shape of a half-sphere or a cup makes the bell to ring once it is hit by the hammer (Avison, 1989).
5. e) Spring_ which is in the shape of a coil, is used for pulling the soft-iron armature which in return pulls the hammer back once the flow of electric circuit is broken

Step by step working principle of an electric bell

When the switch is closed or pressed, the circuit complete and current flow of current through it.

The electromagnet is powered hence produces a magnetic field which attracts the iron strip to it

The clapper or striker strikes the bell (gong)

When the gong is hit by the striking arm, the contact is broken thus making the flow of electric current through the circuit to stop

This in turn causes the electromagnet to lose its magnetism or magnetic field

The connected spring arm pulls back the clapper to its initial resting position

Contact is restored again and once again there is the flow of electric current through the circuit- as much as the main switch is still closed

The process is repeated again from the start (Hasluck, 2011).

Personal observation, recommendation and suggestions to improve the function, materials selected and the manufacturing process

In regards to the above diagram, the one end of the framework winding gets connected to the terminal T1 and the other to the spring that is fixed on the soft iron strip. The rod is then fixed to the armature at the same time its free end triggers a small hammer that strikes the bell.connected to the screw is a light spring which is joined to terminal T2 (Hasluck, 2011).

Although the modern decorative bells can be manufactured from materials such as wood, horn, clay, and glass, the bells which are designed to play music or ring can be cast in a bronze alloy i.e. the combination of copper and tin. The reason for this is because this kind of alloy produces a strong and long-lasting material which resists rusting.

Contrary to the above views, in order to understand the operating principal of the electric bell, one should first understand what an electromagnet is. An electromagnet is made by winding a wire on a soft iron core as shown in the figure above. Therefore, it should be understood that an electromagnet majorly works the same way as a standard magnet –producing magnetic field –although only through the influence of electric current (WAGmob, 2014). When the generation of power to the electromagnet is stopped, the continuous generation of magnetic field also stops.

Moreover, as a customer buying this device, there is the need of understanding the operating voltage of the electric bell. The reason for this is because each bell is designed for a particular purpose for instance, those meant for industrial purpose usually operates at higher DC or AC while those for residential operate at lower voltages.

Results and conclusion

It is noted that electric bells are relatively environmental friendly. This is because once they are installed and operated properly, they does not result to the production of irritating sounds or just to say sound pollution.

An electric bell, as a bell which is activated through the effects of magnetic fields of an electric current, works on the basis of an electromagnet. This is an artificial magnet that is made through coiling wire around a soft-iron core. When current is made to flow through it becomes a magnet. These bells are of many types i.e. interrupter bells, buzzers bells, single/double-stroke bells, telephone and fire alarms. Each one of them is designed for a particular purpose.

 

 

 

 

Bibliography

Avison, J. (1989). The World of physics. Cheltenham: Nelson.

Hasluck, P. N. (2011). Metalworking: Old-fashioned tools, materials, and processes for the handyman. New York, NY: Skyhorse Pub.

WAGmob, (2014). Grade 7 Science- simpleNeasyBook. WAGmob Press

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