STH6 series

60°C – 200°C
AC 277V 13.5A … 35A
DC24V 60A
automatically resetting
Metal housing

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Our STH6 series thermoswitch is a high quality component, which is characterized by its outstanding features. With a high switching capacity, a maximum switching current of 35 A and high sensitivity, this thermal switch provides reliable temperature control for a wide range of applications.

The fixed silver contact and ceramic covers are riveted together, while the moving contact, bimetal disc and spring washer are connected by shaft pins. The moving contact is in close contact with the fixed silver contact under the bias pressure of the spring washer, creating a closed circuit.

The operation of the STH6 series is as follows: When the circuit is working normally, the movable contact and the fixed silver contact are in a closed state. As soon as the nominal operating temperature is reached, the bimetal washer is deformed by heat and the spring washer is pressed down by the riveted shaft pin. This causes the movable and fixed silver contacts to open abruptly. After the circuit is broken, the ambient temperature drops again. As soon as the defined reset temperature is reached, the bimetal disc snaps back to its initial position, the contacts close again, and the circuit returns to its normal operating state.

The STH6-U1 is a variant with the following specifications:

  • Normally closed (NC); automatic reset
  • With connecting cables, epoxy resin and Mylar-Nomex insulation
  • Nominal switching temperature (NST) in 5K steps
  • Tolerance for NST (60 … 140°C): ±5K
  • Tolerance for NST (145 … 200°C): ±10K
  • Tolerance for reset temperature (RST) ≥35°C (≤ 130°C NST): -85K±15K
  • Tolerance for RST (≥ 135°C ≤ 190°C NST): -90K±15K
  • Thickness: 6.8 mm
  • Diameter: 9.5 mm
  • Insulating cap length: 16 mm
  • Resistant to impregnation
  • Suitable for installation in protection class I + ll
  • Pressure resistance of the switch housing: 600N
  • Standard connection: 1.0 mm² / AWG17
  • Insulation voltage: 2.0 kV
  • Recognized standards: UL/VDE/CQC
  • Operating voltage range AC/DC: up to 500 V AC / 28 V DC
  • Rated voltage AC: 250 V (VDE) 277 V (UL)
  • Rated current AC cos ϕ = 1.0 /cycles: 13.5 A / 10,000
  • Maximum current AC cos ϕ = 1.0 /cycles: 35 A / 2,000
  • Rated current AC cos ϕ = 0.6 /cycles: 9A / 10,000
  • Rated voltage DC: 24.0 V
  • Maximum switching current DC /cycles: 60.0 A / 3,000
  • Total bounce time: < 1 ms
  • Contact resistance: ≤ 50 mΩ
  • Vibration resistance at 10 … 60 Hz: 100 m/s²

The Alpha Therm thermal switch STH6 series is the ideal solution for precise temperature control, enabling reliable performance in a wide range of applications. With its robust design and high-quality construction, it guarantees a long service life and optimum functionality.