TDK führt ThermoFuse-Varistoren für Hochstrom-Überspannungsschutz ein

Surge Protection Components for Industrial and Energy Systems:
In power electronics, renewable energy systems, and telecommunications infrastructure, surge protection components play a crucial role in protecting equipment from transient overvoltage events. TDK Corporation has introduced the MT40 series ThermoFuse varistors, a new generation of surge protection components that combine compact dimensions with enhanced electrical protection performance.

Measuring 38.0 × 15.2 × 40.9 mm (L × W × H), these components incorporate patented overmolding technology along with an integrated thermal shutdown system. This design enables protection against surge currents of up to 50 kA while maintaining a reduced installation footprint.

Typical applications include photovoltaic systems, industrial power supplies, outdoor lighting systems, telecommunications infrastructure, and surge protection devices (SPDs).

Integrated thermal protection and compact design:
ThermoFuse varistors combine a metal oxide varistor (MOV) with a thermal shutdown mechanism that disconnects the component from the circuit when overheating occurs. This integrated protection mechanism helps prevent thermal runaway and increases system safety during extreme electrical events.

The MT40 series utilizes overmolding technology to encapsulate the protection component and thermal shutdown system in a single compact unit. This integration allows system designers to reduce the number of components while maintaining reliable surge protection performance.

The devices use ribbon leads and feature a uniform electrode footprint across the series, facilitating easy integration into printed circuit board layouts.

Electrical performance at high surge currents:
The MT40 series is designed for environments with high energy surges. The components support a peak surge current of up to 50 kA (8/20 μs pulse) and a short-circuit current rating (SCCR) of up to 200 kA according to UL 1449 requirements.

The varistors are suitable for systems with AC voltages from 150 V to 550 V and DC voltages from 200 V to 750 V, making them suitable for use in a wide variety of industrial power and electrical applications.

The series is recognized as a UL 1449 Type 1CA component assembly and supports integration into surge protection devices for both AC and DC circuits.

Monitoring and safety functions are also included.
To support system monitoring, the MT40 series can be equipped with a galvanically isolated, normally open microswitch. This feature enables remote status indication and integration into monitoring circuits that track the operating state of the surge protection component.

A visual indicator is also available as an option, allowing maintenance personnel to quickly determine whether the protection element has been activated or deactivated.

The components are designed for an operating temperature range of -40°C to +85°C, making them suitable for use in outdoor or industrial environments where equipment may be subject to large temperature fluctuations.

Materials and Environmental Compliance:
The MT40 varistors are embedded in a flame-resistant epoxy coating, providing mechanical protection and enhancing safety under fault conditions. The components are RoHS, REACH, and PFAS compliant and are manufactured using lead-free materials.

By combining high surge current capability, integrated thermal protection, and a compact design, the MT40 series offers system developers surge protection components suitable for modern industrial power supply systems, communication infrastructures, and renewable energy installations.

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