Temperature Switch
A temperature switch is an electromechanical device that automatically opens or closes an electrical circuit when the ambient temperature reaches a preset limit. They function to prevent equipment from overheating or overcooling by activating or deactivating a process when a specific temperature is reached.
Key Features
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Temperature Sensing
A probe or sensing element (like a bimetal disc or resistance thermometer) detects the ambient temperature.
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Switching Action
When the temperature reaches a preset "setpoint," the switch's contacts quickly change state (snap) from open to closed or vice versa, and remain in that state.
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This feature prevents the contacts from "creeping" between open and closed states, ensuring the switch remains in its new state until the temperature moves back across the reset point.
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A necessary characteristic that includes a temperature range between the tripping point and the reset point, preventing nuisance alarms from rapid temperature fluctuations.
Types of Temperature Switches
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Utilize a bimetallic strip that expands when heated, triggering a snap-action mechanism to open or close the circuit.
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Use a resistance thermometer to measure temperature, then an electronic evaluation circuit determines the switching point.
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Involve a fluid-filled bulb system where liquid expansion due to heat increases pressure, activating a connected switch.
Customization & Connectivity
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Contact Options
Switches are available with normally open (NO) or normally closed (NC) contacts, which define the switch's state at room temperature.
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Displays & Output Signals
Electronic switches can feature digital displays and output standard signals, such as 4 to 20 mA, for integration with other systems.
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Integrated Features
Some models offer additional options like control lamps, second switch outputs, or compatibility with specific measurement elements like Pt1000 sensors.
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Custom Configurators
Online tools allow users to configure temperature switches to exact specifications for specific applications.
Common Applications
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Machinery Protection: Prevents overheating or overcooling of machinery and equipment.
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Industrial Processes: Monitors and controls temperatures in various industrial applications.
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HVAC Systems: Regulates air temperature in ducts, monitors return air, and protects evaporator coils from freezing.
