Step-Up Transformer

 To Buy Auto Transformers Call TEMCo for the Guaranteed Lowest Price  -  1-800-613-2290
Auto Transformer

Auto Transformers

Step-Up Transformer  Step-Up Transformers 
Step-Down Transformers  TEMCo Step-Down Transformers 
What is a Transformer? Selection of an TEMCo Transformer 
Low-Voltage Transformers Buck Boost Transformers 
Three-Phase Transformers Auto Transformers

Auto Transformers come in many sizes.

Step-Up Transformer Home
Links, Information & Listings
for types of Step-Up Transformers. Access to wholesale pricing!

Step-Up Transformers
Details and further information regarding installation and basic configurations.

Step-Down Transformers
Fundamental data regarding transformers used in step-down applications.

TEMCo Step Down Transformers
A basic description and links to TEMCo transformers recommended for step-down applications.

What is a Transformer?
Essential data about the design and use of a transformer.

How to select a TEMCo Transformer
from a reliable leading American transformer distributing company.

Low-Voltage Transformers
Descriptions and uses of transformers specializing in low-voltage applications

Buck Boost Transformers
This special type of transformer described and explained. Includes links to sites where they can be purchased.

Three-Phase Transformers
Why are there three-phase transformers, and what do they do? How are they different from single-phase?

Auto Transformers
How do auto transformers differ from other transformers? Links to catalog pages included.

Auto Transformers


Auto TransformersAuto Transformers are actually built with the equivalent of only one winding.  Two-winding transformers can be connected to reproduce the same effect.  The single winding version has as a limit that it is most efficient when the difference between the input and output voltages are closest.  As the difference becomes greater, efficiency suffers, and so does the advantage of this design.

While an Auto Transformer loses the advantage of the isolation existing between two separate windings, there are several advantages to an Auto Transformer. 

  • A single circuit that is split into a primary and secondary produces the desired effect using less materials for both wire and core. This is economically desirable.

  • In Auto Transformers converted from two-winding transformers, they lose some advantage in savings of materials, but gain back economic advantage by virtue of the in-series nature of the configuration causing it to produce far higher output.

  • Lower losses contribute to increased efficiency.

  • Less material used results in lower weight.  This can be a factor in where and how they are installed, and the difficulties encountered.  It can also be a positive factor in portable applications.

  • Reactance is reduced in an Auto Transformer and thus results in better regulation characteristics.

Auto Transformers are used in static balancers, boosters and motor starters.  They are used in adjusting single and three-phase line voltages to meet specified needs, and are particularly useful in matching line voltage to a protected equipment application.  They are often a form of Low Voltage Transformer, Step Up Transformer or Step-Down Transformer.

Another wide-spread use of Auto Transformers is in a specialized arrangement in which one of the contacts for the secondary winding in a single winding transformer is adjustable.  The contact is tapped via a brush which can be moved and therefore allows the output voltage to be changed.  A fixed A.C. voltage supply thus becomes variable.

These are used in:

  • Variable D.C. arrangements (incorporating a diode bridge)

  • Voltage Stabilizers

  • Dimmers

  • Motor Starters

  • Etc.

TEMCo offers a variety of Auto Transformers and brands.  Through TEMCo you can buy a top-quality Auto Transformer competitively priced and often get same day delivery.   Check with us to see if you need a Custom-made product.  See the How to select a TEMCo Transformer page to the left for specifics on planning.

Contractors and individuals who need portable power sources and lighting may also want to check out the Diesel Generators available through TEMCo.Auto Transformers can be ordered from TEMCo. TEMCo also carries several other top brands.

Call (510) 490-2187
(US & International)
 or 1-800-613-2290 (US only)
for prices and information.
Wholesale Pricing Available!


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Auto Transformers

Transformer Resources:

Isolation Transformers
Isolation transformers of all types, including custom order equipment built to your specifications!

Medical Isolation Transformers
A source for a broad selection of medical grade isolation transformers, including custom order equipment built to your specifications!

Buck Boost Transformers
A wide range of Buck Boost Transformers and brands to select from.

Custom Transformers
Your specific needs can be supplied here with limited
delay and great pricing on custom designed equipment.

Step-Down Transformers
Power Transformers designed to reduce voltage to an optimum range. Descriptive data included.

Step-Up Transformers
Power Transformers designed to increase voltage to an optimum range. Descriptive data included.

AC Line Reactors
Listings of 3 phase devices used as filters rather than for changing voltage.

Acme Transformers
An expansive selection of Power Transformers for all applications.

Hammond Transformers
Primarily dealing in copper-wound transformers.

Jefferson Transformers
All American-made products. Located in Brownsville, Texas.

Static Phase Converters
Critical information regarding the difference between static phase and rotary phase converters. A must for anyone considering these alternatives!

Phase Converter
Read about the technology differences between the types of phase converters available from this top phase converter manufacturer.

Diesel Generators
Access information and pricing on a variety of brands and types of diesel generators designed to fit every need! Custom-built generators can also be ordered.
Top Diesel Generator Models available wholesale including PTO Generators and Mobile Light Towers.


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