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PTC Thermistor

Insta Control's PTC Thermistor offers protection against:

  • Single Phasing
  • Under/ Over voltage
  • Continuous overloading
  • Intermittent duty or Excessive start/ stops
  • Insufficient ventilation or Excessive ambient temperature
  • Mechanical jamming/ Overloading
  • Bearing failure

Our PTC Thermistors are manufactured in accordance with the international standards DIN 44081, 44082 and BS EN 60034-11:2004. Due to their small thermal mass, they have favorable temperature sensitivity.

Insta PTC Thermistors should be placed as near as possible to the hot spot. In three phase motors, one PTC Thermistor should be embedded in each phase. Good thermal contact between PTC Thermistor and winding is essential. The PTC Thermistors should be embeded parallel to the winding.

In this way the mechanical stresses on the PTC Thermistors during forming the end turns of overhang winding can be minimized. Shrink cap is especially well suited for this because of its mechanical stability. At ambient temperature, resistance of one thermistor is between 20 ohms to 250 ohms. The resistance increases sharply in the region of the nominal response temperature. Response times < 5 sec. are achieved with Insta Thermistor.This signal can be used to switch off power circuit of electric motors/ transformers by using Insta's Thermistor Protection Unit.

Insta can supply customised connections with customised individual lead lengths, cross-sectional areas, crimped contacts etc.