Exploring Current Sense Transformers

Posted by Bill Dull | May 15, 2024 0 Comments

Commonly employed in high-current circuits, current sense transformers (CSTs) are a type of instrument transformer used to measure current values in a conductor.

In current transformers (CTs), the primary has very few windings and is connected in series with the conductor carrying the current to be measured. The secondary contains a number of windings that are wound around a secondary ferromagnetic core. Current transformers are sometimes referred to as “series transformers” because the primary winding — which always has very few turns — is in series with the current-carrying conductor supplying the load.

Since these transformers are essentially a type of step-up transformer, the current in the primary produces a corresponding reduced current in the secondary. This current can be measured using an ammeter and, knowing the turns ratio of the transformer, the current in the primary can be calculated.

Common Applications for Current Transformers

Providing reliable current sensing with minimal insertion loss, current sense transformers are used extensively in high-power applications and power transmission lines.

Current transformers can be employed to perform circuit control, as well as measure current for power measurement and control. They may also be used in safety protection and current limiting applications.

And since current sense transformers can drastically step down current levels, these devices are ideal for use with small, accurate instrumentation. Common applications for current sense transformers include wattmeters, watt-hour meters, power factor meters, and protective relays. These transformers may also be used as trip coils in magnetic circuit breakers (MCBs).

High-Frequency and Low-Frequency Transformers

current sense transformer

Our current transformers for high- and low-frequency applications make use of specially selected core materials tailored to specific frequency ranges. These devices can measure current for a range of different frequencies in various applications. And to meet all of our clients’ unique needs, we offer several types of high-quality current transformers that can be employed at extreme frequencies.

Our CST Series Low Frequency Current Sense Transformers are ideal for operation between 50 and 60 Hz, while our CST Series High Frequency Current Sense Transformers are designed to monitor current at 250 Hz and higher. The CST206/CST306 Series High Frequency Current Sense Transformers, meanwhile, can operate effectively over a frequency range of 20 kHz to 200 kHz. The transformers in this series are constructed of UL-rated 130 °C (266 °F) materials, allowing for use in harsh environments. These frequency ranges cover most of industry’s practical applications.

Learn More

As a world-class manufacturer of transformers and transformer parts, Triad Magnetics is proud to offer some of the most reliable current sense transformers on the market. Dedicated to constant innovation and creative design, our expert team can provide solutions for even the most unusual current sensing requirements.

Our in-house design and manufacturing teams add speed to the product delivery process without compromising design flexibility, and we work closely with clients throughout every step of the selection process to ensure they receive a solution that meets their exact needs.

To learn more about our current sensing options, request a quote from the team today. We’re on hand to answer any questions you may have.


Topics: current sense transformers