Non-Reset Device
Non-Reset types of bimetallic controls are devices which again are generally used as over temperature protectors in applications. These devices will function much like a manual reset type device in that their primary function is to interrupt the electrical load of an application based on increases in the operating temperature. In some application types, design engineers may want to incorporate an extra degree of safety that goes beyond the functionality of a manual reset device. The difference is that once a non-reset type device functions in an application, the end consumer is not able to reset the control and the application will require servicing by an authorized technician in order for the application to function again.
These devices utilize a specially formed bimetallic element which is designed to operate in a temperature range that is determined by the design engineer. The difference is that due to the special form in the bimetal element, the thermal control will not reset unless it is exposed to temperatures around 5° C or less. These devices offer the functionality of a single operation thermal control but unlike a thermal fuse, they can be tested for function prior to use in the application.