Auto Transformers

When electrical isolation is not needed, we can work to provide autotransformers that can provide the voltage step-up or step-down, but with lower sizes and costs:

  • Either step-up or step-down,
  • Smaller size, compact transformers,
  • Lower cost transformers,
  • 1-Phase and 3-Phase,
  • Multiple primary or secondary voltages accomodated,
  • Available open frame or in a NEMA rated enclosure

Order Now

All of our units are built-to-order, in either production-run or prototype quantities. Contact us to determine your specifications and get your requirements down. If you don't know everything, that is okay, we can help. Call us at US +1 408-263-8444, or email us by clicking the button below:

ISO 9001:2015 icon These transformer are NRTL to UL 506 and 1561. Find out more about our certifications by clicking here: More on certifications

Build configurations and capabilities

Electrical Characteristics

50VA up to 1.5MVA

1-Phase, 3-Phase

50Hz and/or 60Hz, 400Hz up to 20,000Hz

Up to 600Vrms input

Up to 600Vrms output

NRTL to UL 506 or 1561

Terminal Configurations

Copper buss bar

Silicon bronze hardware

Terminal strip

Ring-lug compatibility

Touch-safe configurations

Lexan covers

Enclosures and weather

NEMA enclosures

NEMA 1: General purpose

NEMA 3: Weather-resistant (falling dirt, windblown dust, rain, sleet, snow, formation of ice)

NEMA 3R: Same as 3, omits protection against windblown dust

NEMA 4: Watertight

NEMA 4X: Same as 4, but stainless steel

NEMA 6: Submersible

Examples of Auto Transformers


Auto Transformer

3-Phase, 60Hz

Input = 600V ±5% taps

Output = 480V @ 193A

NEMA3R enclosure

NRTL to UL 1561


160kVA transformer

3-Phase, 60Hz

Input = 505V wye

Output = 480V

NEMA3R enclosure

NRTL to UL 1561