TDK launches compact ThermoFuse varistors for 50 kA surge protection

TDK has introduced a new line of surge protection components tailored for industrial and infrastructure electronics. The MT40 series of ThermoFuse varistors from the company offers a blend of high surge capacity, compact design, and integrated safety functionalities. These components are engineered to provide robust protection in challenging electrical settings while also managing system size effectively.

Engineers working on power and infrastructure equipment stand to benefit from this innovation as it could streamline surge protection design processes and enhance reliability and monitoring capabilities within their systems.

Compact Design with High Surge Capability

The latest MT40 series combines a varistor with a thermal disconnecting system in a single compact package measuring 38.0 x 15.2 x 40.9 mm. Through the use of patented overmolding technology, these devices can withstand peak surge currents of up to 50 kA utilizing the standard 8/20 µs pulse waveform.

Aside from its impressive surge performance, the components boast a short-circuit current rating (SCCR) of up to 200 kA in accordance with UL 1449 requirements. This unique blend of surge capacity and fault protection is specifically targeted at applications exposed to severe electrical transients.

TDK has confirmed that the MT40 series is classified as a UL 1449 Type 1CA component assembly, allowing for deployment in both AC and DC surge protection scenarios. These devices are compatible with AC voltages ranging from 150 V to 550 V and DC voltages between 200 V and 750 V.

Built for Industrial and Infrastructure Electronics

The MT40 series finds its application in various settings such as PV systems, industrial power supplies, outdoor lighting infrastructure, telecommunications equipment, and surge protection devices (SPDs). In these environments, protection components must endure high surge currents while ensuring safe operation and system availability.

To facilitate system monitoring and integration, the devices can be equipped with a galvanically insulated, normally open micro-switch that enables remote indication and monitoring. Additionally, an optional visual indicator can signal device status, simplifying maintenance in field installations.

These varistors are engineered to function within temperatures ranging from -40°C to +85°C, rendering them suitable for outdoor and industrial use.

Safety and Sustainability Considerations

TDK has placed a strong emphasis on safety and environmental compliance in the design of the MT40 series. The components are encased in a flame-retardant epoxy coating, enhancing fire safety in fault conditions.

This series complies with RoHS, REACH, and PFAS requirements while utilizing lead-free materials. According to TDK, these attributes align with their broader sustainability objectives while ensuring reliability in demanding electrical applications.

By combining high surge capability, monitoring features, and compact packaging, the MT40 ThermoFuse varistors are positioned as a protection solution for next-generation industrial, renewable energy, and communications systems.