What is a rectifier transformer? 

By on


ABB Rectifier Transformer

I've recently come across this question a couple times browsing the internet. Decided to give a quick answer here.

A rectifier transformer is a transformer which includes diodes or thyristors in the same tank. Voltage regulation may also be included. Rectifier transformers are used for industrial processes which require a significant direct current (dc) supply. Typical processes would include dc traction, electrolysis, smelting operations, large variable speed drive trains, etc.

The application for which the transformer is used, will drive the design considerations including:

  • bridge type connection of the thyristors for higher voltages
  • interphase connection for low voltage, high current applications
  • number of pulses (6, 12 and higher with phase shifting)
  • eddy current and harmonic issues

Voltage regulation is achieved with no-load or on-load tap changers on the high voltage side. Fine levels of voltage regulation can be achieved using saturable reactors on the secondary side. Regulation units may be built in or separate.

If anyone has any comments or rectifier transformer experience to share, please add it below.



Steven McFadyen's avatar Steven McFadyen

Steven has over twenty five years experience working on some of the largest construction projects. He has a deep technical understanding of electrical engineering and is keen to share this knowledge. About the author

myElectrical Engineering

comments powered by Disqus

  1. amsh's avatar amsh says:
    5/17/2013 6:04 PM

    Thanks for sharing the information. Can you please explain the harmonic issues and eddy currents?


Comments are closed for this post:
  • have a question or need help, please use our Questions Section
  • spotted an error or have additional info that you think should be in this post, feel free to Contact Us



Lead us, Warleader

Delum, who had watched all in silence, his face empty of expression, now spoke in turn. ' "Lead us, Warleader, into glory."' Reading is something I do...

Why a Sine Wave?

I received this question by email a few weeks. First thoughts was that it is a product of the mathematics of rotating a straight conductor in a magnetic...

Autonomous Vehicle Challenge

Two driverless and solar power vans have departed from Italy on their way to China via the silk road. During the 13,000 kM trip the vans will drive themselves...

How a Digital Substation Works

Traditionally substations have used circuit breakers, current transformers (CT), voltage transformers (VT) and protection relays all wired together using...

Dielectric loss in cables

Dielectrics (insulating materials for example) when subjected to a varying electric field, will have some energy loss.   The varying electric field causes...

Generator Sizing & Operation Limits

When selecting a generator, there are inherent limits on the active and reactive power which can be delivered. Generators are normally sized for a certain...

Medium Voltage Switchgear Room Design Guide

Many medium voltage (MV) indoor switchgear rooms  exist worldwide. The complexity of these rooms varies considerably depending on location, function and...

IEC 61439 Verification Methods

The (relatively new) switchgear and control gear standard, IEC 61439 'Low-voltage switchgear and controlgear assemblies' has three methods which can be...

Difference Between Live and Dead Tank Circuit Breakers

A quick post in connection with an email question: Live Tank - the circuit breaker the switching unit is located in an insulator bushing which is live...

Tech Topics/Application Notes - Siemens

There are a lot of interesting two page type notes on various medium voltage topics – switchgear, circuit breakers, bus systems etc. It is on the Siemens...

Have some knowledge to share

If you have some expert knowledge or experience, why not consider sharing this with our community.  

By writing an electrical note, you will be educating our users and at the same time promoting your expertise within the engineering community.

To get started and understand our policy, you can read our How to Write an Electrical Note