• Single Phase, Self Hold
  • Thermal Overload Protector (TOP)
  • Switches

Krishna 3MPI Series Self Hold single phase Thermal Overload Protector (TOP) switches are developed for 120 and 250 vac application, due to growing demand for non self re-setting over load protector for motor protection against current fluctuation and overheating. We have developed self hold motor protector by using PTC pills it operates in wider temperature and current ranges than afforded by other available protection devices. The main functions of pct. pill is to hold the heat until per supply is on, to prevent over protector is excellent. The protector will be operate by the current tend heat received from the surrounding area. Electrical circuit will be break when protector reaches at its pre-set open temperature or by the excess current supply than the specified limit. PTC will not be allowed the protector to auto reset as it will hold the heat until power supply is continued. When power suppler will be switched off the PTC pill release the heat and protector will resets automatically at re-set desired temperature.

Key Features

  • Provide significant level of safety for application which has rotating part connected to it
  • Available with variety of terminal configuration for easy mounting and handling
  • Customised coding and colour of coding tape can be provided
  • Positive snap action disc for contact break & make
  • Wide range of current temperature setting for maximum design flexibility
  • Temperature settings as per customer’s specifications.
  • Opening (cut off) temperature is constant within ± 5° C
  • Wide section of lead wire and insulating sleeves.
  • Cadmium free contacts


Krishna 3MPI Self Hold (TOP) switches are used to provided safety to wide range of domestic and industrial electric motors.

Some typical applications are:

  • Dryers
  • Washing Machines
  • Single phase electric motor
  • Pumps
  • Others as per customer design and applications
  • Dish Washers
  • Vacuum Cleaner
  • Trimmers
  • Lawn Mowers