Three Phase Transformer: Working Principle, Types, Applications and Selection Guide

Three Phase Power Transformer Guide with Types, Applications and Complete Transformer Solutions for Industrial and Utility Systems

Introduzione

A three phase transformer is one of the most widely used electrical transformers in industrial power distribution systems. It is designed to transfer electrical energy between three-phase power circuits while changing voltage levels efficiently and safely.

Three phase transformers are commonly used in:

  • Fabbriche industriali
  • Edifici commerciali
  • Sottostazioni di utilità
  • Centrali solari
  • Progetti nel settore dell'energia eolica
  • Mining facilities
  • Centri dati
  • Manufacturing plants

Compared with single phase transformers, a three phase transformer provides higher power capacity, improved efficiency, and better load balance, making it the preferred solution for medium voltage and high-power electrical systems.

As an experienced three phase transformer manufacturer, EverNew Transformer provides customized transformer solutions from Da 15 kVA a 500 MVA, tra cui:


What Is a Three Phase Transformer?

A three phase transformer is an electrical transformer designed for three-phase alternating current (AC) systems.

Unlike a single phase transformer, which operates with one alternating voltage waveform, a three-phase transformer uses three separate phases with a 120-degree phase difference.

The three phases provide:

  • Higher power transmission efficiency
  • Reduced conductor size
  • Better motor performance
  • More stable industrial power supply

A typical three phase transformer contains:

  • Three primary windings
  • Three secondary windings
  • Nucleo magnetico
  • Sistema di isolamento
  • Sistema di raffreddamento
  • Transformer enclosure

Three Phase Oil Immersed Transformer for Industrial Power Distribution Systems and Utility Substation Applications


How Does a Three Phase Transformer Work?

The operating principle of a three phase transformer is based on electromagnetic induction.

When AC voltage is applied to the primary winding, it creates alternating magnetic flux inside the transformer core. This magnetic flux induces voltage in the secondary winding.

The voltage conversion ratio depends on the relationship between winding turns:

Voltage Ratio = Primary Turns / Secondary Turns

For example:

Trasformatore step-down

Input:

13.8kV

Output:

480V

The transformer reduces medium voltage electricity to a usable low voltage level for industrial equipment.

Three Phase Transformer Types

Three phase transformers can be classified according to construction, insulation method, cooling system, and application.

1. Three Phase Dry Type Transformer

A three phase dry type transformer uses air as the cooling and insulation medium instead of transformer oil.

Dry type transformers are widely used where fire safety and environmental protection are important.

Advantages of Dry Type Transformer
Elevata sicurezza antincendio
Nessun rischio di perdite d'olio
Requisiti di manutenzione ridotti
Adatto all'installazione in ambienti interni
Rispettoso dell'ambiente
Common Applications

Three phase dry type transformers are commonly installed in:

Edifici commerciali
Ospedali
Aeroporti
Centri dati
Impianti industriali
Shopping centers

Typical ratings:

Capacità Applicazione
15 kVA Small commercial loads
45 kVA Industrial equipment
75 kVA Building power supply
500 kVA Factory distribution
2500 kVA Large industrial systems

EverNew manufactures dry type transformers with:

  • Copper winding
  • Aluminum winding
  • Cast resin insulation
  • UL/CSA compliant designs

Three Phase Dry Type Transformer Coil Manufacturing and Copper Winding Process for Industrial Power Transformer Production


2. Three Phase Oil Immersed Transformer

A three phase oil immersed transformer uses insulating oil for cooling and electrical insulation.

Oil immersed transformers are commonly used for outdoor power distribution because they provide excellent heat dissipation and high capacity capability.

Vantaggi

  • High power capacity
  • Excellent cooling performance
  • Lunga durata
  • Suitable for outdoor applications

Applicazioni

Tra le applicazioni più comuni figurano:

  • Sottostazioni di utilità
  • Fattorie solari
  • Fattorie eoliche
  • Impianti industriali
  • Power transmission systems

Typical voltage ratings:

  • 6kV
  • 10kV
  • 11kV
  • 13.8kV
  • 35kV
  • 110kV
  • 220kV

3. Three Phase Distribution Transformer

A three phase distribution transformer is designed to reduce medium voltage electricity to low voltage for end users.

Typical conversion:

11kV → 400V

13.8kV → 480V

35kV → 400V

Applicazioni:

  • Zone residenziali
  • Commercial facilities
  • Fabbriche industriali

4. Three Phase Power Transformer

A trasformatore di potenza trifase is used in high voltage transmission and substations.

Applicazioni:

  • Power plants
  • Grid substations
  • Progetti di energia rinnovabile

Gamma di potenza:

From several MVA to hundreds of MVA.

High Quality Three Phase Transformer Winding Production Process with Copper Windings for Industrial Power Transformer Manufacturing


Three Phase Transformer Applications

Sistemi di alimentazione industriali

Factories rely on three phase transformers to supply power for:

  • Motori
  • Compressors
  • Pumps
  • CNC machines
  • Production lines
  • Automation equipment

Industrial transformers usually require:

  • High efficiency
  • Funzionamento continuo
  • Strong overload capability

Edifici commerciali

Three phase transformers are commonly used in:

  • Edifici adibiti a uffici
  • Hotels
  • Centri commerciali
  • Aeroporti

A common North American system:

480V → 208Y/120V

This voltage system is widely used for:

  • Lighting
  • Impianti di climatizzazione
  • Building equipment

Progetti di energia rinnovabile

Solar and wind projects require transformers to increase voltage before grid connection.

Esempio:

Solar inverter:

800V

Transformer:

0.8kV / 35kV

Grid connection


Three Phase Transformer Voltage Ratings

Different countries use different voltage standards.

Nord America

Common voltages:

Tensione primaria Tensione secondaria
480V 208Y/120V
600V 347/600V
13.8kV 480V
34,5kV 480V

International Markets

Common systems:

Primary Secondary
10kV 400V
11kV 415V
20kV 400V
35kV 400V

EverNew transformers can be designed according to:

  • CEI
  • ANSI
  • IEEE
  • UL
  • CSA
  • CE
  • GOST

Three Phase Transformer Manufacturing Process in Modern Transformer Factory with Advanced Production Technology


How To Select A Three Phase Transformer?

Choosing the correct transformer requires evaluating several technical parameters.


1. Transformer Capacity (kVA)

The transformer capacity must match the electrical load.

Common sizes:

  • 15 kVA
  • 30 kVA
  • 45 kVA
  • 75 kVA
  • 112,5 kVA
  • 150 kVA
  • 500 kVA
  • 1000 kVA
  • 2500 kVA

2. Input and Output Voltage

Esempio:

Commercial building:

Input:

480V Three Phase

Output:

208Y/120V Three Phase


3. Frequency

Common frequencies:

  • 50Hz
  • 60Hz

4. Transformer Cooling Method

Choose according to installation environment:

Indoor:

Trasformatore a secco

Outdoor:

Trasformatore a bagno d'olio


5. Transformer Standards

I progetti internazionali potrebbero richiedere:

  • UL certification
  • CSA certification
  • DOE efficiency
  • Norme IEC
  • Standard IEEE

Outdoor Three Phase Pad Mounted Distribution Transformer for Utility Substation and Renewable Energy Power Projects


Three Phase Transformer Manufacturer

Selecting a reliable three phase transformer manufacturer is important for ensuring safety, efficiency, and long service life.

A professional transformer supplier should provide:

✔ Engineering design support

✔ Factory testing

✔ International certifications

✔ Customized voltage solutions

✔ Export experience


Perché scegliere il trasformatore EverNew?

EverNew Transformer is a professional transformer manufacturer in China with more than 30 years of experience.

Le nostre capacità produttive comprendono:

Product Range

  • Trasformatore di distribuzione
  • Trasformatore a secco
  • Trasformatore a bagno d'olio
  • Trasformatore montato su pad
  • Trasformatore di potenza

Technical Capability

Capacità:

15 kVA – 500 MVA

Tensione:

6kV – 500kV

Certificazioni

  • UL
  • CSA
  • CE
  • GOST
  • ISO

We supply transformers for:

  • STATI UNITI D'AMERICA
  • Canada
  • Sud America
  • Europa
  • Asia
  • Africa

Three Phase Transformer FAQ

What is the difference between single phase and three phase transformer?

A single phase transformer is normally used for smaller loads, while a three phase transformer is designed for industrial and commercial power systems requiring higher capacity.


What is the most common three phase transformer voltage?

Common systems include:

  • 480V
  • 208Y/120V
  • 400V
  • 415V
  • 13.8kV
  • 35kV

How much does a three phase transformer cost?

Il prezzo dipende da:

  • Transformer capacity
  • Voltage rating
  • Copper or aluminum winding
  • Metodo di raffreddamento
  • Standard richiesti
  • Order quantity

How do I choose a three phase transformer size?

You should consider:

  • Total connected load
  • Starting current
  • Future expansion
  • Voltage requirements
  • Efficiency requirements

Conclusione

A three phase transformer is an essential component in modern electrical power systems, providing efficient voltage conversion for industrial, commercial, and renewable energy applications.

Choosing the correct transformer requires careful evaluation of:

  • Power capacity
  • Voltage levels
  • Metodo di raffreddamento
  • Installation environment
  • Standard internazionali

Come professionista three phase transformer manufacturer, EverNew Transformer provides reliable transformer solutions worldwide with customized designs from low voltage distribution systems to high voltage power networks.

Contact EverNew Transformer today for your three phase transformer project.

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