Why we use Strips on AC Motor?
Today we will know why Strips are used on the body of an AC motor. Whereas if we look at the DC motor, there is no strip on it. So what is the reason behind this, we know that. Why Strips Used in AC motor?
This question can also be asked within the electrical interview, so we will also know what to answer in the interview.
Friends, we all know the difference that on AC motor we get to see the strip, but DC motor is absolutely plane. And with this help, we recognize the AC motor and DC motor many times.
But if we know the reason behind this, then it is quite easy, the work of the straps on the AC motor is only to protect the motor from overheating.
Ac motor cooling fan
As we know. We also attach a cooling fan to the motor rotor. Due to which the fan also starts running when the motor is running and this fan is put in such a way that its entire air goes on the strips above our motor. So that the motor keeps cooling and the motor is not very hot.
But inside the electrical interview, you are asked other questions besides this. You will be asked inside the interview, why these strips are only above the AC motor or why only we give cooling to the AC motor. Why not supply DC motors?
Why Strips only used in AC motors?
As we know, Ac motor runs on alternating current. So when we give this AC current to the winding inside our motor, then the magnetic field is created near our winding.
Magnetic-field
And this is a magnetic field made of AC supply, the magnetic lines change frequently. So we call this kind of magnetic field a changing magnetic field. And with the help of this changing magnetic field, we can rotate the motor rotor.
But along with the advantages of this changing magnetic field, we also see some disadvantages.
To know what harm we have from this, you must know one rule.
This rule states that if a metal comes in the middle of a changing magnetic field (metal means any metal substance). So at that time, this changing magnetic field gets linked to that metal of ours. And as these magnetic lines link up, an electromotive force (voltage) is generated inside our metal, meaning the pressure is generated. And due to this electromotive force, a current starts flowing from inside the metal, which we call Eddy Current.
Ac motor eddy current
Similarly, an eddy current is generated inside the motor also, and it starts flowing on the main body of our motor ie the frame. But there is no need for this eddy current motor, it only serves to heat our motor. Due to which the motor starts heating up, and due to this, the problem of burning the motor also comes.
So to protect the motor from heating at this time, we make the strips on the frame of the motor. After this, with the help of a cooling fan, the air from the strips is passed, so that the motor does not get too hot.
Now, friends, this question will come to the minds of many people. If this Eddy current is of no use to us, then why don't we end it.
So, the answer is quite simple and it is also very easy to reduce the eddy current.
How to reduce Eddy's current?
The metal you are using to reduce the eddy current. Do not use it in a solid, instead, you use several thin pieces of metal by insulating them together, this reduces the eddy current.
For Example: If you have ever seen the core of a transformer, then that transformer core is made up of many thin seats. So that the current loss is minimized and the transformer is not too hot.
But now this question will come to the mind of all of us. Why don't we eliminate the Eddy current by using thin seats inside the motor too?
So, let me tell you what is the stator inside the motor. The motor winding on which we make is made of thin laminated cores. So that the eddy current is not there and our motor is also not unduly hot.
But the main body of our motor, which means frame, is made of solid metal. Because of this, Eddy current flows easily in the frame of the motor.
If we want, we can also make the frame of the motor consisting of thin pieces. But we do not do this because we want the outer surface of the motor to be very strong. So that the motor does not break easily due to any reason. Meaning we use solid metal inside the motor frame to give the motor a mechanical stand.
Questions asked ln Interview?
Q.1 Why are strips mounted on an AC motor?
Answer- With the help of these strips, the motor gets good cooling, due to which the motor is not heated.
Q.2 Why only AC motor needs cooling?
Answer - AC motor needs cooling due to Eddy current loss. This eddy current starts flowing into the frame of the motor, due to which the motor starts heating up. So the motor is not too hot at this time. For this, we put a band on the AC motor and it will work well.
Hope you must have got answers to many questions related to your Why we use Strips on AC Motor today.
Thank You!
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