Überhitzungsschalter

An überhitzungsschalter, also known as an overheat switch or thermal cutout, is a safety device designed to prevent damage to electrical or mechanical equipment by interrupting the power supply when a dangerously high temperature is reached. It is a type of temperature-sensitive switch that operates based on the principle of thermal expansion or a change in material properties at a specific temperature.

The most common type of überhitzungsschalter utilizes a bimetallic strip. This strip is composed of two different metals with varying coefficients of thermal expansion. When the temperature rises, one metal expands more than the other, causing the strip to bend. This bending action can be engineered to open an electrical contact, thereby breaking the circuit and shutting off the device. Once the temperature drops below a certain threshold, the bimetallic strip returns to its original position, and the circuit is restored, often referred to as a self-resetting feature.

Another type of überhitzungsschalter employs a fusible link, which is a wire or element made of an alloy with a precisely known melting point. If the temperature exceeds this melting point, the fusible link melts, permanently opening the circuit. These are typically non-resettable and require replacement after activation.

Überhitzungsschalter are widely used in a variety of applications, including electric motors, heating elements, power supplies, transformers, and small appliances like hair dryers and kettles. They play a crucial role in preventing fires, equipment failure, and ensuring user safety by automatically shutting down devices that are operating outside their safe temperature range. The specific activation temperature is determined by the design requirements of the protected equipment.