In this tutorial, we explain the formula for three-phase and single-phase transformers, in order to perform the calculation of power transformers. You will be able to calculate various parameters such as amperage, voltage, etc. And we suggest an app to enhance calculations more quickly.It seems that your message is incomplete or contains only HTML tags. Could you please provide the text you would like me to translate?

A transformer is an electrical device whose operation consists of converting the input voltage to a different output voltage.It seems that your message is incomplete or contains only HTML tags. Could you please provide the text you would like me to translate?

We recommend an Excel file for performing various calculations, which can be found in the Hotmart Store.

According to Ohm’s law, we know that if the voltage increases, the current decreases. And if the voltage decreases, the amperage increases.

## Summary.

Find the app at the end of this article

### Conversion of KVA to Kw.

**1 KVA = 1,000 VA**

### Single-phase transformer calculation.

### Three-phase transformer calculation.

### Electrical transformer diagram.

The capacity of a transformer is measured in Power, with units of Volts-Amperes (VA), and the input voltage and output voltage must be specified.

A diagram of a transformer is as follows:

As we can see in the diagram above, there are two sides of the transformer: the primary and the secondary.

For the industry, transformer values are expressed in KVA, that is, Kilo Volt Ampere.

**1 KVA = 1,000 VA**

### Kilo volt ampere (KVA) to Kilo watts (KW)

In theory, one KVA is worth the same as one KW.

However, by convention and to avoid overloading the transformer, it is said that one kW is 90% of one kVA. The expression is as follows:

**KW = 0.9 KVA**

## Single-phase trasnformer.

The equation for a single-phase transformer is:

Dónde:

P: Power in Volts Ampere

V: Phase voltage, in volts

I: Phase current, in amperes.

The primary and secondary of the transformer have the same power; what changes is the amperage and the voltage.

Of course, in a real transformer, there are losses, so the power of the secondary will be a bit lower; the transformer’s plate should indicate its efficiency.

## Three-phase transformer.

The equation for a three-phase transformer is:

Where:**P**: Power in Volts Ampere**V**: Phase voltage, in volts**I**: Phase current, in amperes.

The primary and secondary of the transformer have the same power; what changes is the amperage and the voltage.

## Ejercicios.

### 1.- Calculate the current of the secondary of a single-phase transformer of 15 KVA, if the secondary voltage is 220 V.

Let’s do it in the app.

**RE: 68.18 A**

### 2.- Calculate the capacity in KVA of a three-phase transformer, which measures 220 V on the secondary side and 65.608 A.

RE: 25 KVA

### 3.- We have a single-phase transformer of 450 VA and we want to know what the current will be if we apply 120V to the primary.

RE: 3.75 A

Check your results in the app:

* Electrical calculations according to NOM 001 SEDE 2012*, are useful for obtaining the Verification

**Unit for electrical installations. (UVIE).**

The transformer needs to be protected against short circuits, for this, fuses are used. You can watch the transformer protection tutorial.