#WishIknew – What’s a variable frequency drive?


When you have a question about process automation that needs a short answer, let us know with #WishIknew and @Visaya! We’ll reply with a #WishIknew post. It’ll give a quick explanation, then some related articles, videos, or reviews if you want to know more.

I wish I knew what a variable frequency drive is!

The variable frequency drive controls one of the final control elements in a control loop. If you don’t know what a final control element is, then you need to read this article before you continue.

This electronic device usually controls the speed of an alternated current motor. It can control the motor’s rotation through a frequency change in its output signal.

The frequency of the motor’s power supply sets the speed of the motor. So when you install a variable frequency drive, it will now control the frequency to change the motor’s speed. When the frequency increases the speed also increases, and when it decreases the speed will also decrease.

Using a variable frequency drive can bring a lot of advantages to the end user, such as direct braking and controlling speed without affecting torque.  It also offers easy installation,  automation, safety, and energy savings.

Best of all, a variable frequency drive can increase the life of your AC motor. When you turn on the motor directly, it goes straight from full stop to full speed, which puts wear and tear on certain parts of the motor.

With a variable frequency drive, you can create an acceleration ramp, extending the time to achieve top speed. Ramping up the acceleration reduces damage on the internal components, increasing the lifetime of those parts and the motor itself.

This video has more details about the variable frequency drive:

Related tags: #WishIknew Basic devices English Final control elements Frequency driver Measurement Principle Variable frequency driver
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