Applications for a bimetal temperature swtich
- Mobile hydraulics
- Machine building
- Cooling and heating circuits
Special Features of a bimetal temperature switch
- Fixed switching temperature
- Current-independent switching
- Automatic reset
- No additional voltage supply
- Simple and fast mounting
Description of a bimetal temperature switch
Bimetal temperature switches are generally used to monitor the temperature of machinery and equipment. For example, if temperature limits are reached the temperature switch engages to swtich off machinery, preventing it from overheating or the temperature switch may activate a fan to cool the equipment.
Bimetal temperature switches are comprised of a a bimetal disc, which snaps over when the nominal switching temperature (NST) is reached.
When the equiment or machinery cools down to the reset switching temperature (RST), the switch returns to its original state.
The bimetal disc in WIKA’s model TFS35 bimetal temperature switch carries no current, which eliminates the possibilty of arcing.
With current-carrying bimetal discs there is also a danger of the temperaure switch prematurely switching because of higher self-heating.
The reset switching temperature of a bimetal temperature switch is typically 15 … 30 K below the switching temperature.
The model TFS35 bimetal temperature switch can be delivered in two contact designs.
A Normally Closed (NC = closed in the normal state) opens a circuit and shuts down the machinery.
A Normally Open (NO = open in the normal state) closes a circuit on reaching the switching temperature, in order that, for example, a fan or warning lamp can be switched on.
In both cases, on cooling down below the reset switching temperature, the contacts return to their original state, so that the monitored equipment can again work normally.