30R400UMR Circuit Protection

Polymer Positive Temperature Coefficient (PPTC) Resettable Fuses are sometimes referred to as ‘multifunctional devices’, as they combine circuit protection, isolation, interference suppression, and in some cases even self-regulation. They are installed in electronic devices to protect components from overcurrent, short-circuits and overloads.

The 30R400UMR is a PPTC Resettable Fuse designed for use in DC applications where an over-current protection device is needed. There is no need for external heat dissipation, since the device relies on ‘thermal runaway’ to shut off the power when an overload is detected.

Application Field

30R400UMR PPTC Resettable Fuses are used in a wide range of applications, from home appliances, such as washing machines and dishwashers, to medical devices, airplanes, and automotive electronics. Its small size and wide current-handling capabilities make it suitable for a variety of projects, including those with limited space constraints. It is also suitable for use in batteries and other low-voltage applications.

Working Principle

The 30R400UMR PPTC Resettable Fuse works by using a proprietary PTC polymer with a high resistance abruptly increasing when subjected to a certain temperature threshold. The resistance then stays high until the device is cooled down sufficiently. The resistive material also has a relatively low resistance value under normal operating conditions, allowing for efficient power transfer and efficient protection against an overload.

When an over-current passes through the fuse, the Heat Generating Units (HGUs) inside the device start dissipating heat, increasing the temperature at the fuse’s terminals. When the temperature reaches the fuse’s Temperature Activated Resettable (TAR) threshold, the resistive material inside the device quickly rises in impedance and silently interrupts power flow.

The 30R400UMR PPTC Resettable Fuse can be reset automatically as soon as the temperature at the fuse’s terminals falls below the TAR threshold. This reset mechanism helps to protect the device from overcurrents, short circuits, and overloads. It also helps to maintain system stability by providing an effective shutoff without the need for manual resetting.

The 30R400UMR PPTC Resettable Fuse provides an effective and reliable method of protecting electronic devices from over-currents, short circuits, and overloads. Its small size and wide application range make it a popular choice among product designers and engineers. Its efficient reset function helps maintain system integrity and reliability.