BACK BONE OF MODERN TECHNOLOGY : INDUCTION MOTOR AND ITS WORKING !!!!
Hello friends today I am here with one of the most fascinating topics in the field of engineering and technologies the induction motor
we all know the importance of induction motor in life this invention permanently altered the course of human civilization, in turn, resulting in human modernization. This was invented by Nichola tesla and is now the most common type of motor used
Do we know ????
About 50 % of the global electric power consumption is due to induction motors
An INDUCTION motor consists of
1. stator (stationary part)
2. rotor (rotating part )
Stator:
It is basically a three coil winding this winding pass through the slots of the stator which are made by highly permeable steel laminations stacked together inside a cast iron frame (supporting frame)
AC Supply is given to this part of induction motor
When 3 phase current passes through the winding we observe fluctuating magnetic field which is the rotating magnetic field and this magnetic field makes the rotor to rotate
To understand how rotating magnetic fields are produced with its properties
Let us consider a stator winding where three conductors i.e wires are connected with a 3 phase supply i.e the 3 wires are connecting with a phase difference of 120 degrees (voltage)
Now the wire carrying current produces a magnetic field around it if we supply 3 phase power to this arrangement the magnetic field produced will be as shown
with variations in ac currents, the magnetic field takes different orientations. If compare the graph at some instants we can see that the magnetic field of uniform strength is rotating and the rotation speed of the rotating magnetic field is called synchronous speed (Ns)
Rotor: It is the rotating part of the induction motor and we will see it in action below
According to Faraday's law we know that the varying magnetic field produces an induced emf and this emf produced will produce a current in the loop hence current carrying loop is placed in the magnetic field
According to Lenz law an electromagnetic force will be produced on the loop with this force the loop starts rotating This is the same phenomenon in working of induction motor
WORKING OF INDUCTION MOTOR :
Here instead of a simple loop, a squirrel cage is used. The three-phase AC supply produces a rotating magnetic field. hence the current is induced in the bars of squirrel cage and this is shot by end rings so that the rotor will start to rotate .because of current induced on the rotor due to electromagnetic induction
This is the reason why the name induction motor is coined for this electrical device
To help such electromagnetic induction a laminated iron core is placed inside the rotor these laminated iron sheets reduces the power loss due to eddy currents
We can observe the electric and magnetic fields rotating and by altering them we can alter the speed and functioning of an induction motor
Case 1 If the Ns is equal to Speed of rotor
The magnetic field will never cut the loop resulting in no emf inside the coil. this translates to zero force on the rotor
Case 2: Ns>N
As it slows down the magnetic field cuts the loop inducing a current in the rotor which will increase the force acting on it hence the rotor rotates
And the ratio of difference b/w Ns and N to Ns is called slip and this always lies b/w 0 and1
Slip = (Ns-N)/Ns
Advantages of induction motor are :
1. It has simple and rugged construction due to which the induction motor is ruling the world
2. It is self-starting
3. The speed of induction motor can be controlled easily by controlling frequency
( Ns is directly proportional to input frequency hence N is also proportional to the frequency )
Heres my question to you all how can we generate electrical power using induction motor ????
Let's stop until here and learn about working of electrical vehicles in my next blog
Comment down your answers!!!!!!
we all know the importance of induction motor in life this invention permanently altered the course of human civilization, in turn, resulting in human modernization. This was invented by Nichola tesla and is now the most common type of motor used
Do we know ????
About 50 % of the global electric power consumption is due to induction motors
An INDUCTION motor consists of
1. stator (stationary part)
2. rotor (rotating part )
Stator:
It is basically a three coil winding this winding pass through the slots of the stator which are made by highly permeable steel laminations stacked together inside a cast iron frame (supporting frame)
AC Supply is given to this part of induction motor
When 3 phase current passes through the winding we observe fluctuating magnetic field which is the rotating magnetic field and this magnetic field makes the rotor to rotate
To understand how rotating magnetic fields are produced with its properties
Let us consider a stator winding where three conductors i.e wires are connected with a 3 phase supply i.e the 3 wires are connecting with a phase difference of 120 degrees (voltage)
Now the wire carrying current produces a magnetic field around it if we supply 3 phase power to this arrangement the magnetic field produced will be as shown
with variations in ac currents, the magnetic field takes different orientations. If compare the graph at some instants we can see that the magnetic field of uniform strength is rotating and the rotation speed of the rotating magnetic field is called synchronous speed (Ns)
Rotor: It is the rotating part of the induction motor and we will see it in action below
According to Faraday's law we know that the varying magnetic field produces an induced emf and this emf produced will produce a current in the loop hence current carrying loop is placed in the magnetic field
According to Lenz law an electromagnetic force will be produced on the loop with this force the loop starts rotating This is the same phenomenon in working of induction motor
WORKING OF INDUCTION MOTOR :
Here instead of a simple loop, a squirrel cage is used. The three-phase AC supply produces a rotating magnetic field. hence the current is induced in the bars of squirrel cage and this is shot by end rings so that the rotor will start to rotate .because of current induced on the rotor due to electromagnetic induction
This is the reason why the name induction motor is coined for this electrical device
To help such electromagnetic induction a laminated iron core is placed inside the rotor these laminated iron sheets reduces the power loss due to eddy currents
We can observe the electric and magnetic fields rotating and by altering them we can alter the speed and functioning of an induction motor
Case 1 If the Ns is equal to Speed of rotor
The magnetic field will never cut the loop resulting in no emf inside the coil. this translates to zero force on the rotor
Case 2: Ns>N
As it slows down the magnetic field cuts the loop inducing a current in the rotor which will increase the force acting on it hence the rotor rotates
And the ratio of difference b/w Ns and N to Ns is called slip and this always lies b/w 0 and1
Slip = (Ns-N)/Ns
Advantages of induction motor are :
1. It has simple and rugged construction due to which the induction motor is ruling the world
2. It is self-starting
3. The speed of induction motor can be controlled easily by controlling frequency
( Ns is directly proportional to input frequency hence N is also proportional to the frequency )
Heres my question to you all how can we generate electrical power using induction motor ????
Let's stop until here and learn about working of electrical vehicles in my next blog
Comment down your answers!!!!!!
Tq sir for this information...
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