High Voltage Transformers

Designed in a collaborative effort between your staff and ours, designs are available in:

  • Up to 250kVrms, 350kVDC
  • 1-Phase and 3-Phase,
  • Available open frame or in a NEMA rated enclosure,

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We can help to support your high voltage transformer needs. Contact us to determine your specifications. Call us at US +1 408-263-8444, or email us by clicking the button below:

Outside testing may be needed if required by the customer or dictated by the specifications.

Our High Voltage Transformers

A high voltage transformer is a transformer having input our output voltages that are significantly higher than common line voltages. These are designed and tested to a higher dielectric test voltage than the operating voltage it is designed to produce.

High voltage refers not only to high output voltage but to high-voltage isolation and high-voltage rectification as well. High voltage isolation transformers are highly insulated from primary to secondary and secondary to ground. These are used to isolate the high voltage components from the rest of the system. Units in this category can either be single or three-phase and like all of our products, are designed specifically to meet each customer's needs.

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 250kVrms, 350kVDC input

Up to 250kVrms, 350kVDC output


Customer specified: up to 250kVrms, 350kVDC



Oil: mineral or silicone

Gas: sulfer hexaflouride and freon

Epoxy: materials/techniques vary with required properties

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

Examples of High Voltage Transformers


High voltage transformer


3-Phase, 50Hz

Primary = 11kVrms L-L

Secondary = 32 secondaries


HV rectifier transformer


3-Phase, 60Hz

Primary = 480Vrms w/taps

Secondary = 17.6kVDC