Advertisements
Advertisements
प्रश्न
Draw figure ‘Electric motor’ and working
Advertisements
उत्तर
Electric motor:
Working: When a current is allowed to flow through the coil MNST by closing the switch, the coil starts rotating anti-clockwise. This happens because a downward force acts on length MN and at the same time, an upward force acts on length ST. As a result, the coil rotates anti-clockwise.
Current in the length MN flows from M to N and the magnetic field acts from left to right, normal to length MN. Therefore, according to Fleming’s left hand rule, a downward force acts on the length MN. Similarly, current in the length ST flows from S to T and the magnetic field acts from left to right, normal to the flow of current. Therefore, an upward force acts on the length ST. These two forces cause the coil to rotate anti-clockwise.
After half a rotation, the position of MN and ST interchange. The half-ring D comes in contact with brush A and half-ring C comes in contact with brush B. Hence, the direction of current in the coil MNST gets reversed.
The current flows through the coil in the direction TSNM. The reversal of current through the coil MNST repeats after each half rotation. As a result, the coil rotates unidirectional.
APPEARS IN
संबंधित प्रश्न
Name any four appliances where electric motor is used.
Name some devices in which electric motors are used
Explain the construction and working of an electric motor.
Explain the function of the following parts of an electric motor.
Armature
Label the four parts of an electric motor
Electric motor works on the magnetic effect of electric current.
A motor converts one form of energy into another. Name the two forms.
Name the device which is used to reverse the direction of current in the coil of a motor?
Fill in the following blank with suitable words:
Fleming's Rule for the motor effect uses the .......... hand.
Fill in the following blank with suitable words:
A motor contains a kind of switch called a .......... which reverses the current every half .......... .
What is the principle of an electric motor?
In a d.c. motor, why must the current to the coil be reversed twice during each rotation?
What is an electric motor? With the help of a labelled diagram, describe the working of a simple electric motor
In an electric motor, the direction of current in the coil changes once in each:
two rotations
one rotation
half rotation
one-four rotation
Name some of the devices in which electric motor are used.
Electric motor : converts electrical energy into mechanical energy : : Electric generator : _______
What is an electric motor?
In which electric motor appliances do we use it?
State whether true or false. If false, correct the statement.
A generator converts mechanical energy into electrical energy.
State whether true or false. If false, correct the statement.
The speed of rotation of an electric motor can be increased by decreasing the area of the coil.
An electric motor is a device which transforms ____________.
In an electric motor, to make the coil rotating continuously in the same direction, the current is reversed in the coil after every half rotation by a device called ____________.
Commercial electric motors do not use ____________.
Draw an appropriate schematic diagram showing common domestic circuits and discuss the importance of fuse. Why is it that a burnt out fuse should be replaced by another fuse of identical rating?
How can the speed of rotation of a coil be increased? Write at least three methods.
Define electric motor.
