explain the working of an electric motor
Answers
Explanation:
Electric motors involve rotating coils of wire which are driven by the magnetic force exerted by a magnetic field on an electric current. They transform electrical energy into mechanical energy.
Electric motor
An electric motor is a rotating device that coverts electrical energy to mechanical energy. Electric motors are used in MP3 players,, washing machines, computers etc.
Set-up:
An electric motors as shown in attachment consists of a rectangular coil ABCD of insulated copper wire. The coin is placed between the two poles of a magnetic field such daddy on AB and CD are perpendicular to the direction of magnetic field. The ends of the coil are connected to the two halves P and Q of a split ring. The inner rings of these halves are insulated and attached to an axle. The external conducting ages of P and Q touch two conducting stationary brushes X and Y respectively.
Working:
- Current in the coil ABCD enters from the source battery through a conducting brush X and follows back to the battery through brush Y. Note that,direction of flow of current in CD is opposite to the direction of current through arm AB.
- On applying Fleming's left hand rule we found that the force acting on arm AB pushes it down words while the force acting on an CD pushes it upwards. A torque acts on the coil and it rotates anticlockwise.
- While rotating the coil reaches the vertical position, brushes lose contact with the rings and current stops flowing. But the coil does not stop does not stop due to inertia of motion.
- When coil passes through the opposite direction, the rings automatically change their direction, and come in contact of opposite brushed.
This reverses the direction of the current through coil but the direction of current on right hand side remains the same.
- So, the force on right hand side is always upwards and a force on left hand side is always in downward direction. Thus,coil continues to rotate in anti clockwise direction.
