Miniature current transformer with split core 125-5A class 1 TOM-125-5

Precise current measurement in a compact form

The miniature split-core current transformer TOM-125-5 is a professional solution for measuring current intensity in electrical installations. Thanks to the 125/5A ratio and accuracy class 1, the device ensures precise transformation of high current values into standard 5A measurement signals, compatible with most monitoring and measuring instruments.

Construction and materials

The transformer features a single-phase split-core design, which allows for installation on existing conductors without the need to disconnect them. The split-type core ensures easy installation and removal during installation or maintenance. The compact housing with dimensions of 45×67×35 mm fits into standard distribution boards, and the fi22 mm aperture diameter allows for installation on conductors with significant cross-sections.

Electrical parameters and safety

The device operates at a rated primary current of 125A, transforming it to a secondary current of 5A. The apparent power is 1.5 VA, which is optimal for most measurement applications. The design provides an insulation breakdown voltage of approximately 2 kV per minute, guaranteeing safe operation in installations with voltages up to 0.66 kV AC.

The safety factor FS ≤ 2 protects against overloads, and the operating frequency of 50÷60 Hz covers standard power grid requirements. An operating temperature from -15°C to +45°C enables application in various environmental conditions.

Mounting and connection

The transformer is mounted on a rail or directly on the conductor using a mounting hole with dimensions of 60×35 mm. The secondary winding is brought out through S1/S2 screw terminals, which allow for a solid connection to the measurement circuit. It is recommended to use conductors with a minimum cross-section of 2.5 mm² for the secondary connection and to ground the S2 terminal to ensure proper operation and safety.

Compliance and standards

The product meets the requirements of the IEC 60044-1 standard, confirming its compliance with international standards for measuring transformers. The IP20 protection rating provides basic resistance to touch and dust, suitable for indoor installations. The device has an accuracy class of "1", which guarantees high measurement precision in professional monitoring and measuring applications.