WIKA,TFS35双金属温度开关Bimetal temperature switch热电偶开关

Bimetal temperature switch
Model TFS35

Bimetal temperature switch, model TFS35

   Applications
   ■ hydraulics
   ■ Machine building
   ■ Compressors
   ■ Motors
   ■ Cooling and heating circuits

   Special features
   ■ Fixed switching temperature
   ■ Current-independent switching
   ■ Automatic reset
   ■ No additional voltage supply
   ■ Simple and fast mounting

  Description
   Temperature switches are generally used in industry for limiting temperature. They monitor the temperature of machinery and equipment and, for example, switch off
machinery if it overheats or switch on a fan to cool the equipment.

   Function
   Bimetals form the basis of the WIKA TFS35 temperature switches. Temperature sensing is carried out by a bimetal disc, which snaps over when the nominal switching temperature （NST） is reached.

   On cooling back down to the reset switching temperature （RST）, the switch returns to its original state.

   The bimetal disc in the model TFS35 bimetal temperature switch carrys no current, and this eliminates the possibility of arcing.

   With current-carrying bimetal discs there is also a danger of premature switching as a result of higher self-heating.

   The reset switching temperature is typically 15 ... 30 K below the switching temperature.
   Contact design
   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.

  Max. switching voltage
    Resistive load （cos ? = 1）:
   ■ AC 48 V, 3 A
   ■ DC 24 V, 3 A
   ■ DC 12 V, 4 A

  Contact resistance
   < 50 mΩ

  Dielectric strength
   AC 1,500 V, 50 Hz
   between electrical connections and housing

  Temperature ranges
   ■ Nominal Switching Temperature （NST）
   50 ... 200 °C

  Note:
   The nominal switching temperature can be selected in steps of 5 K. It is preset on delivery and cannot be changed.
   ■ Switch point accuracy
      ±5 K
   ■ Reset Switching Temperature （RST）
   The reset switching temperature in bimetal temperature switches is typically 15 ... 30 K below the switching temperature.
   To ensure a safe reset of the switch at low switching temperatures, care must be taken that the temperature difference between the measuring point and ambient is
high enough; since otherwise the switch cannot cool back down to the reset switching temperature and thus the equipment will not be able to return to its normal state.
   ■ Ambient temperature
      -50 ... +125 °C

  Note:
   With small insertion lengths there is a possibility that the temperature at the connector can reach impermissibly high values. This absoluy must be taken into account in the design of the measuring point.

  Thermowell
  Material
   ■ Brass
   ■ Stainless steel

   Stem diameter D
   ■ 10 mm
   ■ Thread size （version without stem）

  Process connection
   Mounting thread:
   ■ G ½ B
   ■ G ¼ B
   ■ G ? B
   ■ M14 x 1.5
   ■ M22 x 1.5
   ■ ¼ NPT
   Others on request

  Insertion length U
   ■ 30 mm
   ■ 40 mm
   ■ 50 mm
   ■ Thread length （version without stem）
   Others on request

  Response time
   The response time is srongly influenced by
   ■ the thermowell used （diameter, material）
   ■ the heat transfer from thermowell to the switching element
   ■ the flow-rate of the medium

   Due to the design of the model TFS35 bimetal temperature switch, there is optimum heat transfer from the medium to the switching element.

  Vibration resistance
  Due to the specific assembly of the switching elements used, the vibration resistance of the model TFS35 bimetal temperature switch is very high.
  Depending on the mounting situation, the medium, temperature and insertion length, the vibration resistance is up to 10 g.

 Shock resistance
  Up to 100 g, depending on the mounting situation, medium and temperature

  Working pressure
  Max. 100 bar, depending on the medium, temperature and thermowell design
Electrical connection
  ■ Rectangular connector per DIN EN 175301-803, Form A （replacement for DIN 43650）
  ■ Connector AMP Junior Power Timer, contacts gold-plated
  ■ FASTON blade terminals 6.3 x 0.8 mm
    Other connections on request

  Ingress protection
   IP 65 when connected