NCERT Class 10 Physics: Motor, Working Principle, And Its Applications

NCERT Class 10 Physics: Motor, Working Principle, And Its Applications - Motors are an essential component of many different devices and systems that we use in our daily lives. For example, Electric motors are used in household appliances such as blenders, washing machines, and vacuum cleaners to generate mechanical motion. Motors are also used in automobiles to power the wheels and other mechanical systems, such as the power steering and the air conditioning.

In the Class 10 NCERT curriculum, students learn about the basic principles of how motors work and how they are used in various applications. This includes topics such as the electromagnetic forces that drive motors, the different types of motors and their characteristics, and the basic principles of electromechanical energy conversion. Students also learn about the different parts of a motor and how they function, as well as the principles of electrical circuits and how they relate to motors. Here in this article, we will discuss motors, their working principle, and their applications in detail. So let's start with the motor.

Electric Motor

A motor is an electrical device that converts electrical energy into mechanical energy. The working principle of a motor is based on the interactions between an electric current and a magnetic field. When an electric current flows through a conductor, it creates a magnetic field around the conductor. This magnetic field can be used to generate motion.

The basic components of a motor include a stator, a rotor, and an armature. The stator is the stationary part of the motor that provides the magnetic field. The rotor is the rotating part of the motor that carries the armature. The armature is a coil of wire that carries the electric current.

Working Principle

When an electric current flows through the armature, it creates a magnetic field around the coil. This magnetic field interacts with the magnetic field of the stator, causing the rotor to rotate. The direction of the rotor's rotation is determined by the direction of the current flowing through the armature and the orientation of the stator's magnetic field. Let's understand the working principle in detail.

In an electric motor, there is a rectangular coil ABCD that is made of insulated copper wire. This coil ABCD is placed between two poles of the magnetic field in such a way that arms AB and CD are perpendicular to the direction of the magnetic field. This end of the coil is connected with two halves of the split ring. These halves are insulated from the inner side and conducted from the external side. The external conducting edges touch to fix brushes X and Y. The current flows from the positive terminal of the battery to the negative terminal of the battery. It flows through brush X to copper wire ABCD then brushes Y to the negative terminal of the battery. We can observe that the current flow in wire AB from A to B and in wire CD from C to D and the direction of the magnetic field is from the North pole to the south pole.

Also, we are aware of Fleming's left-hand rule. According to it, if we stretch out our forefinger, middle finger, and thumb in such a way that all are perpendicular to each other. Here the direction of the thumb represents the force on the conductor, the forefinger represents a magnetic field, and the middle finger represents the current flow in the conductor as shown in the following figure.

After applying this rule we can find the direction of a force in AB and CD wire when current flows from A→B→C→D, the force on wire AB is downward. and on the wire CD is upward. So due to the torque, the armature will rotate. As it turns, the direction of the current changes when brush Y comes in contact with the positive terminal. Now current flows from D→C→B→A. Using Fleming's Law we can find the direction of the force on wire DC and BA. wire DC experience force downward whereas wire BA experience force upward. Thus due to torque, the armature continues to rotate and complete one cycle. This is how our motor works.

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Applications Of Motors

There are different types of motors, each with its own unique characteristics and applications. The most common types of motors include DC motors, AC motors, and stepper motors.

DC Motors

DC motors use direct current (DC) to power the armature. They are widely used in applications that require precise control over the motor's speed and torque. DC motors are commonly found in small appliances such as fans and electric shavers.

AC Motors

AC motors use alternating current (AC) to power the armature. They are widely used in applications that require high power and high speed. AC motors are commonly found in large appliances such as washing machines and refrigerators.

Stepper Motors

Stepper motors are a type of DC motor that can be precisely controlled to move in small increments. They are commonly used in applications that require precise positionings, such as in printers and CNC machines.

The working principle of a motor is not only used in electrical devices, but also in other fields such as mechanical engineering and robotics. For example, in mechanical engineering, the working principle of a motor is used in the design of engines and other machines that generate motion. In robotics, the working principle of a motor is used to power and control the movements of robotic arms and legs.

Also check - JEE Main: Newton's Law Of Cooling

Questions That May Be Asked In Board Practicals

Q-1: What is the principle of an electric motor? State the rule which is applied to determine the direction of force experienced by a current-carrying conductor when kept in a magnetic field. (CBSE 2019 Class 10)

Ans: The working principle of an electric motor is based on Fleming's left-hand rule. A current-carrying conductor experiences force and rotates when placed in a magnetic field.

Fleming's left-hand rule is applied to determine the direction of the force.

Q-2: (a) State Fleming’s left-hand rule.

(b) Write the principle of working of an electric motor.

(c) Explain the function of the following parts of an electric motor.

(i) Armature

(ii) Brushes

(iii) Split ring (CBSE 2018 Class 10)

Ans: (a) Fleming's left-hand rule can be stated as stretching the forefinger, middle finger, and thumb of the right hand such that they are mutually perpendicular to each other. If the forefinger indicates the direction of the magnetic field, the middle finger indicates the direction of current in the conductor then the thumb indicates the direction of the force exerted on the conductor.

(b) The working principle of electric motors is based on the magnetic effect of current. A current-carrying loop experiences a force and so takes when placed in a magnetic field. The direction of rotation of the loop is given by Fleming's left-hand rule.

(c) (i) Armature is a coil that carries current and rotates in a magnetic field.

(ii) Brushes are used to make contact with rotating split rings so as to supply current to the armature.

(iii) Split ring is used for reversing the direction of the flow of current.

Overall, the study of motors in a Class 10 NCERT curriculum can provide students with a foundation of knowledge and understanding that will be useful in many areas of science and engineering. It can also help students develop critical thinking and problem-solving skills that can be applied in a variety of contexts. Also, it helps to get an in-depth understanding of the working principle of a motor which is based on the interactions between an electric current and a magnetic field. This principle is widely used in various fields, from electrical devices to mechanical engineering and robotics.