Zelisko Energy, a subsidiary of Knorr-Bremse Group, has been a trusted
name in the field of instrument transformers for over 60 years. Our
product range includes high-precision, maintenance-free current and
voltage transformers designed for both indoor and outdoor applications
across low, medium and high voltage systems. These transformers are
known for their durability, operating reliably in diverse environmental
conditions worldwide.

Zelisko’s state-of-the-art epoxy resin casting technology ensures
long-lasting insulation performance and maintenance-free operation extending product life for many decades. Beyond traditional
transformers, Zelisko also integrates intelligent sensors for monitoring
voltage, current, and system health in real time. These compact, digital ready sensors support grid automation, predictive maintenance, and
accurate metering in both conventional and smart grid infrastructures

Zelisko offers solutions tailored to custom requirements, including
special current and voltage transformers for unique applications. Our
products comply with international standards such as IEC 61869, IEEE
and ANSI, ensuring global applicability and reliability. Our instrument
transformers come with best-in-class rated accuracy with ratio error
as low as 0.2%

Zelisko provides current and voltage transformers and sensors installed in a wide range of high voltage, medium-voltage and low-voltage equipment. These devices deliver essential data for the
supply and transmission of electrical energy. Hundreds of thousands of instrument transformers,
designed and manufactured by Zelisko, are installed across a wide range of applications in the
United States and around the world. These installations reflect decades of proven reliability,
precision, and performance in diverse energy and industrial environments.
Zelisko instrument transformers are available in a variety of designs for both indoor and outdoor
applications. For over 60 years, these high-precision, maintenance-free transformers have
been successfully deployed in all types of installation settings and weather conditions worldwide.
Zelisko also plays a crucial role in the energy transition by supplying current and voltage sensors
for automated transformer substations in medium-voltage smart grids.
Zelisko products blend decades of expertise with forward-thinking engineering and innovation.
A key example is the company’s highly automated epoxy-resin casting process, which ensures
exceptional insulation quality. In addition to standard offerings, Zelisko provides tailor-made
solutions for special applications, delivering customized products designed to meet specific
customer needs and specifications. And it goes without saying that short, reliable lead times are a
standard.
To meet demanding requirements for quality, flexibility, delivery speed and competitive pricing,
Zelisko continually refines its engineering and production systems. In particular, the advanced APG
epoxy-resin casting process, combined with computer-aided product design, gives customers a
distinct competitive edge.
The proven reliability of Zelisko’s power transmission and distribution products is built not only
on cutting-edge technology but also on decades of practical experience. For more than 60 years,
Zelisko instrument transformers have demonstrated their performance in power grids worldwide
– even under the harshest operating conditions