Capacitor, what is it? How to calculate?


What is a capacitor? How to calculate the capacitor? What is the best fan capacitor? When we researched capacitors , those were the main doubts! In this article, the World of Electrical answers all of them, besides giving several tips to teach you how to choose a capacitor and use it correctly.


What is a capacitor?
Capacitors are basically reactive elements, that is, they react to the passage of current through the accumulation of electrical charges. So, the main function of the capacitor is to store electrostatic energy.

In case you don’t know, the most common capacitors are composed of two conductive metal plates, which are separated by an insulating dielectric material. Capacitors can be used in a variety of situations such as assisting in starting a single-phase induction motor.

How to choose the fan capacitor?
Here’s how to calculate the capacitor for an induction motor!

How to calculate the capacitor?
To calculate the capacitance of a capacitor that is used in a single-phase electric induction motor, it is essential to know two important information about the motor, the operating voltage, and the operating current. Knowing this information we can already find out what the capacitor is, and for that, we will need only 2 calculations that are very simple!

In this first calculation we will find out what the inductive reactance is and for those who do not know, the inductive reactance is the resistance of a coil or inductor. In our case, we will find out what the resistance of the motor coil is.

To facilitate your understanding, we will use for example an engine that has the following information:

Operating voltage – 127V
Operating current – 2A
The inductive reactance is represented in the formula by XL, as shown in the following image! To find out what its value is, just divide the voltage by the current, in the case of our example it is 127 divided by 2, which is equal to 63.5 ohms.

Know what electrolytic capacitor is
The formula for calculating inductive reactance

Understand that we use ohm because the inductive reactance is a resistance, and the unit of resistance is ohm! Continuing the calculation and with the defined inductive reactance, we will now find the capacitance. For this, we will use another formula that is also very simple.

Capacitance is represented in the formula by C, as shown in the image below! Note that the capacitance is equal to 1, divided by 2, times PI, times the frequency, times the inductive reactance. In case you don’t know, PI is a constant that is worth 3.14. So, multiplying by 2, we have 6.28, our frequency is 60Hz, and the inductive reactance we calculate is 63.5 ohms.

How to choose the fan capacitor?
The formula for calculating capacitance

When we multiply the bottom of the equation, we get the value of 1 divided by 23,926.8. So, the capacitance is equal to 0.000041 Farad, which is the unit of capacitance. Converting this to the micro submultiple, we have 41 micro Farad. Therefore, we can use a capacitor with a capacitance close to 41 micro Farad.

See how to calculate the capacitor
How to calculate the capacitor for induction motor

You can see that with these simple calculations we can already determine which is the best capacitor for a single-phase induction motor. Therefore, to choose the capacitor of any other motor, just change the values ​​of the operating voltage and operating current.

Here on the website and on the Mundo da Elétrica channel, you will find many free tips and information that can help you stand out in the area. So, if you want to gain even more customers, just continue to train more and more.