Stator winding resistance estimation for temperature monitoring of induction motor under unbalance supplying by DC injection method

In this paper, stator-winding resistance has been estimated for temperature monitoring of induction motor under unbalance supplying condition. For this reason, the resistance of stator winding is estimated under balance and unbalanced condition by injecting a DC signal to AC voltage. In this study, the stator temperature is measured by construction of a temperature measurement system using sensor-installing method. Each method is implemented on the 1.1 kW/50 Hz/1400 rpm three- phase squirrel cage induction motor and experimental results under balanced and unbalance conditions show that the estimated method is capable of responding to changes of the motor thermal characteristics, resulting in reliable thermal protection.