Why VFD Drive Used on Motor?

why-vfd-is-used

If you are from electrical engineering, you must have heard the name of VFD starter, or you have seen VFD installed on the motor in the industry. But if asked why VFD is applied to the motor?

So some people can’t answer this question, but some people give 4-5 reasons for this question, but if they are asked which is the main reason among these all reasons, then they get confused and cannot give the correct answer.

what is VFD

Today’s post will discuss the main reason for using VFD. We will also talk about the other benefits of VFD. So let’s know the main work of VFD, then we will discuss all the other benefits separately.

Why is VFD used on the motor?

Friends, if asked in the interview, tell the main reason for using VFD on the motor. So you have to give a simple answer: we use VFD to control the speed of the motor. Because friends all other starters we have, such as DOL starter, star-delta starter, or soft starter, we cannot control the speed of the motor with any of them.VFD-working

Speed ​​control means how fast our motor is rotating; we can control that speed according to us. So with the help of VFD, we can control the speed of the motor according to us. But friends, now you can be asked in the interview that after all, how do we control the speed of the motor with VFD, so let’s understand the answer of this question.

How to control Speed with VFD?

Friends, we all know that the electricity supply in our country is AC, which is supplied at 50Hz.

Friends, we don’t give direct supply to the motor whose speed is to be controlled. First, we connect the supply wire to the VFD. Then we supply electricity to the motor from VFD.

So now, if we want to reduce the speed of the motor, then The AC supply which was coming to us at 50Hz, we reduce that frequency like 40Hz, 30Hz, we reduce the frequency according to the speed we want to reduce.speed control from VFD

Similarly, if we want to increase the speed, then we increase the supply frequency, such as 60Hz, 70Hz we increase the frequency accordingly to speed.

So friends, if you ask the main reason for using VFD, now you can easily tell that VFD is used to control the speed of the motor, but if in the interview asked what other benefits can be had by using VFD, so let’s understand the what answer you have to give.

Advantages of VFD

Friends, apart from speed control from VFD, there are many benefits such as:

  1. Energy saving: Friends, for example, our motor is 15kw, and when we don’t need full power of the motor, then at that time we can reduce the speed of the motor by reducing the frequency, due to which the motor will take less power. In this way friends, our energy is saved by VFD.VFD-energy-saving
  2. Power Factor improves: Friends, we want the industry’s power factor to always remain between 0.99 to 1. Because if the power factor goes below 0.80, the government can impose a penalty. We also get an additional advantage of power factor improvement by using VFD. improve power factor VFD
  3. Smooth start: Using VFD, our motor gets a smooth start and smooth stop. Smooth start means that when our motor starts, the starting current is very high at that time motor suddenly rotates very fast, if our motor is not fitted well then the motor starts moving too much or else Our motor can also get damaged due to high starting current. The VFD makes our motor run slowly and off and on.VFD motor protection
  4. To Protect Motor: Apart from all this, the most important VFD use is to give all kinds of protection to the motor. VFD provides all types of protection to the motor, such as over current, phase unbalance, phase shifting, overload, short circuit, etc. VFD gives protection from all such faults.

    So, friends, we hope you understand all of VFD’s benefits. If any question is left, you can comment below or send the inquiry to us on Instagram Electrical Dost.”

    If you want to see electrical video, you can visit our channel Electrical Dost.” 

    Thank You 🙂

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Aayush Sharma is an Assistant Engineer in a Semi-Government Company and Owner of "Engineering Dost" and the Electrical Dost YouTube Channel. He Provides you Engineering inquiry and support of engineering market facts with Practical experience.

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