explain the principle construction working and uses of electric motor with the help of a well labeled diagram
Answers
Principle: An electric motor works on the principle that a current carrying conductor placed in a magnetic field experiences a force.
Construction: An electric motor consists of the following main parts:
1. Field magnet: It is a strong horse shoe type magnet with concave poles.
2. Armature: It is a rectangular coil ABCD having a large number of turns of thin insulated copper wire wound over a soft iron core.
The armature is placed between the poles of the field magnet and it can be rotated about an axis perpendicular to the magnetic field lines.
3. Split ring commutator: It consists of a cylindrical metal ring split into two halves S1and S2. The two ends A and D of the armature coil are connected to the split rings S1 and S2 respectively. As the coil rotates, the split rings also rotate about the same axis of rotation. The function of the split ring commutator is to reverse the direction of current in the coil after every half rotation.
4. Brushes: Two graphite or flexible metal rods maintain a sliding contact with split rings S1 and S2, alternately.
5. Battery: A battery of few cells is connected to the brushes. The current from the battery flows to the armature coil through the brushes and the split rings.
Working: Initially, suppose the plane of the coil is horizontal. The split ring S1 touches the brush B1 and split ring S2 touches the brush B2. The current in coil flows in the direction ABCD from the source battery, as shown in Fig.(a).
Clearly, the currents in arms AB and CD are in opposite directions. The force acting on arm AB pushes it downwards while the force acting on the arm CD pushes it upwards. Thus the armature coil alongwith the axle rotates anticlockwise. After half a rotation, as shown in Fig.(b), the split ring comes in contact with brush B2, and S2 in contact with brush B1. Therefore, the current in the coil gets reversed and flows along the path DCBA. A device that reverses the direction of flow of current through a circuit is called commutator. Thus the arm AB is now pushed up and the arm CD is pushed down. Therefore, the coil and the axle rotate half a turn more in the same direction. The reversing of the current is repeated at each half rotation, giving rise to a continuous rotation of the coil and to the axle.
uses- car mixer juicer fan collar
Split ring acts as commutator in electric motors
ANSWER:-
Electric motor is a device which converts electrical energy into mechanical energy.
Principle: electric motor is based on the principle that a current carrying conductor placed perpendicular to the magnetic field experiences a force.
Construction:
Armature coil: it consist of a rectangular coil of wire placed between the poles of a strong magnet.
Strong field magnet: Armature coil is placed between the two poles of a strong magnet. This magnet provides a strong magnetic field.
Split-ring type commutator: It consists of two halves (P and Q) of a metallic ring. The two ends of the armature coil are connected to these two halves of the ring. It reverses the direction of current in the armature coil.
Brushes: Two carbon brushes X and Y press against the commutator. These brushes acts as the contacts between the commutator and the terminals of the battery.
Battery: A battery is connected across the carbon brushes. This battery supplies the current in the armature coil.
Working:
• Initially, the current in the coil ABCD enters brush X and flows back to the battery through brush Y. Thus, the current in the arm AB flows from A to B.
• In arm CD,the current flows from C to D ,that is , opposite to the direction of current through arm AB.
• On applying Fleming’s left hand rule, we find that force acting on arm AB pushes it downwards while the force acting on arm CD pushes it upwards.
• Thus the coil and axle, rotate anti-clockwise.
• After half rotation, Q makes contact with the brush X and P with brush Y. Therefore the current in the coil gets reversed and flows along the path DCBA.
• The reversal of current also reverses the direction of force acting on the two arms AB and CD.
• Thus, now arm AB is pushed up and the arm CD is pushed down.
• Therefore the coil and the axle rotate half turn more in the same direction.
• The reversing of the current is repeated at each half rotation, giving rise to a continuous rotation of the coil and to the axle.
HOPE THAT HELPS!!!
