How does a 3 phase autotransformer function?

How does a 3 phase autotransformer function? We all know that 3 phase transformers mainly include 3 phase autotransformers and 3 phase isolation transformers. How does the 3 phase autotransformer work? Through this content we will understand the working principle of 3-phase autotransformer.

How Does a 3 Phase Autotransformer Function?

1. What is a 3 phase autotransformer?

An Autotransformer is a transformer with only one winding wound on a laminated core. An auto transformer is similar to a two winding transformer but differ in the way the primary and secondary winding are interrelated. A part of the winding is common to both primary and secondary sides.

On load condition, a part of the load current is obtained directly from the supply and the remaining part is obtained by transformer action. An Auto transformer works as a voltage regulator.

Three-phase autotransformer

High quality and safe three-phase autotransformer, rated power 0.5~500 kVA, rated frequency 50/60 Hz, step down input voltage 380V AC to output voltage 220V/200V. Winding material copper or aluminum optional, other primary and secondary voltage can be customized.

Application: 3-phase autotransformer can be used in CNC machine tools, SMT, printing machines, EDM machines, automatic plug-in machines, precision measuring equipment, laser cutting machines, plastic molding machines, medical monitoring systems, PCB drilling machines, laboratory equipment, Military Instrumentation Control Center, etc

2. How does a 3 phase autotransformer function?

The 3 phase autotransformer is designed to reduce the voltage.

A three phase autotransformer will reduce the voltage by changing the number of turns in the secondary winding. The number of turns in the secondary winding is determined by a ratio between that and primary winding.

3-phase autotransformer working principle diagram

Three phase autotransformers consist of a single magnetic circuit with a single primary and secondary winding. The single primary winding is connected to the three phase source, while the single secondary winding is connected to the load. The core acts as a magnetic path for all three phases and consists of one leg (or half) of each transformer.

When considering transformers as such, there are many different types and applications that use them; however, this article will focus on how they work in regards to their function in relation to power systems in general.

3. 3 phase autotransformer features

  • 3 phase autotransformer has enough power, the wiring is tight and neat, and does not skip turns. Coils adopt insulated H-class enameled wire, with low no-load current and low loss.
  • Autotransformer has built-in silicon steel sheet, which has good magnetic flux performance, high heat dissipation coefficient and low magnetic loss.
  • The autotransformer uses electrophoresis technology clamps, no burrs on the edges, rounded corners to prevent collisions, and not easy to corrode.
  • Tinned copper tube terminals and rail-type wiring ports are convenient for wiring and ensure that the power-on overload capacity is increased to the extreme.


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About Me

Hi, I’m tony is the manager of SHUOGONG POWER, more than 16 years experience in transformer industry, I would like to share my experience in transformer & voltage regulator field. SHUOGONG is a leading transformer manufacturer in China. We can solve all your voltage problems. If you have any questions, please feel free to contact me. I will try my best to provide you with voltage and regulation solutions.

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