Thermal cutoff switch

Thermal cutoff switch 

       Thermal switch is an electromechanical device which opens and closes the contacts to control the flow of electrical current in response to temperature change. The term “Thermal Cutoff Switch” generally refers to how the switch is used, ie. It cuts off the current to critical machinery when a temperature limit is exceeded preventing potential burn out or failure.  The applications of, and need for electromechanical thermal switch devices are broad and cover a huge diversity of industrial applications. In their most basic form, they can be found on home appliances such as dryers for over temp protection.  Thermal cutoff switches are also used widely in sophisticated industrial equipment as well as commercial jetliners. There are a number of different technologies used to implement a thermal cutoff switch that rely on expanding elements to provide the movement to open or close contacts, including vapor filled, rod and tube, Bimetal, and  bimetallic disc to name a few.

Applications

        Thermal switches are specified as cutoff switches because they represent a straightforward approach to shutting down a system if a critical temperature is reached. The simplicity of an electromechanical thermal switch is what makes this approach so desirable to designers, as they are passive devices which require no power, and will reliably change state at the specified set point. 

Applications include:

a) Plastics extruder barrel overtemp detection.
b) Brake overtemp indication
c) Engine cooling fan control d) Clutch overtemp in escalators
e) Bleed air overtemp indication on aircraft environmental control systems f) Window defrost overtemp on military vehicles
g) Overtemp in refinery process
h) Avionics overtemp on aircraft avionics
i) Gas shut-off  flame detection on railroad switch de-icing
j) Flame detection in aircraft engines.