Thermorelais Typ 166 431

Type 166 431

Thermal Relay (normally closed)

The thermal relay is suitable wherever a delayed cut-in or cut-out is required in an electrical appliance. Typical applications are electric storage heaters.

Depending on the number of contacts required, the thermal relay consists of 1, 2 or 3 thermostats mounted onto a common baseplate. This assembly is clipped onto a plastic socket which can also be used for fixing. A PTC resistor and 2 push-on terminals for line connection are mounted on the baseplate.

The PTC resistor serves as a heating element for the thermostat(s). As soon as voltage is applied to the PTC, it heats up and transfers its heat to the aluminium baseplate. When the preset thermostat temperature is reached the bimetal disc(s) operate, opening the electrical contact(s). As long as power is fed to the PTC, the bimetal disc(s) remain in position. When the power to the PTC is cut, the baseplate cools down again. The bimetal disc(s) and the contact spring(s) snap back to their original position and close the circuit(s).

  • Quiet contact operation
  • Easy mounting
  • Even heat transmission
  • High force to open contacts
  • Long life

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