Current transformers

Current transformers are key components in electrical energy measurement systems, which enable precise monitoring and control of current in high-voltage circuits. Their main task is to reduce the current to a level that is safe and measurable by standard measuring devices. Onninen offers a wide range of current transformers adapted to various applications and technical requirements, which ensure reliable operation and high measurement accuracy. This is an indispensable solution for the energy industry, automation systems and electrical installations.

What are current transformers used for?

Current transformers are used to measure electric current in circuits, especially those with high voltage, where direct measurement would be dangerous or technically difficult. Their main task is to convert large current values into smaller, proportional signals that can be safely and accurately measured by standard measuring devices such as meters, relays or automation systems. Current transformers can monitor, analyze and control the flow of current in power systems, which is crucial to ensuring their safe and efficient operation.

Types of current transformers

Current transformers are divided into several types depending on the design, purpose and method of installation. Here are the most common types of current transformers:
1. Core transformers:
o Annular (torus): They have a ring-shaped core through which the primary current conductor passes. They are mainly used in places with limited space and in low-voltage installations.
o Single or multi-phase core: Usually have an open or closed core. They are mounted directly on the conductor or current busbar. Examples are current busbar transformers.
2. Insulating transformers (air):
Used in high voltage applications where it is necessary to isolate secondary circuits from primary circuits. They provide additional protection and insulation.
3. Closed current transformers:
Enclosed in a housing, which protects them from mechanical damage and environmental influences. Used in difficult industrial conditions.
4. Laboratory transformers:
Used in measurement and research laboratories for very precise measurements of currents over a wide range of values.
5. Disconnectable (openable) transformers:
They allow for installation without the need to disconnect wires. They are convenient for installation in existing installations, especially in modernized facilities.
6. Electronic transformers (digital):
They convert analog signals into digital signals, enabling their further analysis by control and monitoring systems. Used in modern automation and energy management systems.
7. Indoor and outdoor transformers:
o Indoor: Designed for installation in closed switchboards or control cabinets.
o Overhead: Used in open spaces, more resistant to weather conditions.
Each of these types of current transformers is adapted to specific operating conditions and installation requirements, allowing for precise and safe current measurements in a variety of applications.

How to choose the right current transformer?

Selecting the right current transformer is a process that requires taking into account several important aspects to ensure its reliable and efficient operation in a given electrical installation. Current transformers are key elements that enable safe and precise current measurements, so their proper selection is of great importance.
First, you need to determine the rated current, which is the maximum current that can occur in the circuit. The secondary current, usually 5 A or 1 A, should meet the requirements of the connected measuring devices. The accuracy class of the transformer determines the precision of the measurement - a higher one is necessary for accurate energy measurements, while a lower one is sufficient for general applications. The rated power (VA) must provide power to all connected devices without exceeding the permissible power losses. It is also important to adapt the transformer to the installation conditions - indoor or outdoor - and to specific protective or measuring applications. The transformer must be adapted to the system voltage and meet the appropriate standards and certificates to ensure reliability and safety in various operating conditions.

A wide range of current transformers at Onninen

By choosing current transformers at Onninen, you gain access to a wide range of top-quality products, perfectly tailored to your needs. Our transformers ensure reliability, precision and safety in every installation, regardless of its scale and complexity. Thanks to our experience and expertise, you can count on professional advice and support at every stage of the purchase. Choose proven solutions and trust Onninen – your partner in energy and automation. Check out our offer and choose products that will meet all your expectations!