Induction heaters use the principle of power frequency short circuit current heating bearing, and adopt advanced electronic temperature control circuit, then the temperature can be settled automatically according to the input values in the range of 0-200℃. Set up the highest upper limited temperature in the process of heating, once the temperature reach the highest value, the induction heater can cut the heating circuit automatically and give overtemperature alarm. The heaters use the intelligent dual digital display mode to set up, control and display the temperature. Set time and actual time can be displayed in dual digital display mode. Therefore, user can know the temperature and heating time of the heated inner ring anytime and anywhere. In the heating process, only bearing is hot while the temperature of heater itself keeps normal.