Interphase Transformers

Our Interphase Transformers are generally designed for high voltage applications higher than 100 kVrms. These custom transformers are designed to fit your systems and can either be supplied with oil or without.

Contact Us Now!

Details on our Interphase Transformers

The Interphase Transformer is used “to absorb the difference between the direct voltages of the individual systems and must be designed for the times integral of this voltage” (Schaefer, 1965).

Interphase transformers are used in systems that have two rectifier systems being used in parallel. The need for the Interphase Transformer is present because when connecting rectifiers in parallel, their direct voltages fluctuate. Furthermore, rectifier systems can only be connected in parallel if their fluctuating voltages are equal at any instant. Essentially, their average values must be equal and the ripple voltages must coincide. “Under this condition rectifier installations for very high current ratings are sometimes built of several simultaneously commutating and directly paralleled groups” (Schaefer, 1965). In practice, this setup is rarely found.

It is most commonly desired, instead, to displace the ripple voltages so that the combination results in a system with a higher pulse number. “The parallel connection must then be made in such a manner that it does not affect the operation of the individual groups. This is accomplished with an Interphase Transformer” (Schaefer, 1965).

Technical Capabilities

Interphase transformers are defined much differently than other types of transformers and, therefore, our capabilities are much more loosely defined. While we cannot say we can design any type of IPT, we can design a large spectrum of them. Below we have a mean of the specs we have seen for the different Interphase Transformers we have built. Your application may be different. If it is different, feel free to contact us or let us know what the specs you are looking for and we will work to design and quote you a transformer for your specific needs.

Power Ratings up to 5 MW
  • 50 Hz
  • 60 Hz
  • 400 Hz up to 20 kHz
Current up to 6.5 kADC
Nominal Voltages up to 1.5 kVDC
Current Imbalance up to 6%


We can design our Interphase Transformers with a current rating of around 6,500 Amps DC. This current rating limit is not a hard-cut line, so if you have an application that falls outside of this scope, please feel free to contact us. These current ratings are merely a guideline to what we most commonly see.

Current overloading to increase traction power is often needed. If you have this part spec'd out already, we will need these percentages and currents so we can incorporate them into the designs.