Potential Transformers

RESA Power stocks a wide range of Potential Transformers, including Low Voltage and Medium Voltage potential transformers for most common applications. We offer a large in-stock inventory and same-day shipping.

Potential Transformers vs. Current Transformers

While both current and potential transformers are step-down transformers and critical for the safety of your system, there are some distinct functionality differences between the two. Where current transformers (CT) measure your power systems’ current, potential transformers (PT) measure voltage levels. PT transformers work by proportionally converting the high voltage values within substations to safer, lesser values of 100v or lower so they can be directly and continuously measured.

There are two main types of potential transformers:

  • Wound Type (Electromagnetic) PT Transformers consist of a primary and secondary winding wound around a magnetic core. They use electromagnetic induction to convert high voltage into a safer low voltage for measuring. This type of PT transformer is similar in construction to conventional transformers, however, for voltages above 10kV they are not recommended due to the high cost and demands of its insulation.
  • Capacitor Voltage PT Transformers eliminate the insulation issues that can occur with Wound Type PT transformers by using electrical components, such as capacitors, to convert the primary voltage. This type of transformer can also be divided into capacitors and coupling capacitors, which allows for high-frequency carrier communication. They are suitable for higher voltages and are less expensive to install, however, the output capacity is smaller than that of a Wound Type PT transformer.

RESA Power can help you determine which type of power potential transformer is best for your power systems’ specifications. Our team of certified engineers and technicians can handle everything from custom-fit components to installation, maintenance, and field services. Contact your nearest systems center today to find out how we can help you with all of your low, medium, and high-voltage potential transformer needs.


With distribution and manufacturing centers located across the United States, RESA provides service and support to clients in every major metropolitan area.