Introduction to Simple Speed Control Method For Small Induction Motors Base On Phase Difference Seminar Topic:
This paper proposes method for speed control of induction motor with out of the sensor. There are various methods available for controlling the speed of induction motor but they require additional equipment and expensive. By using a equivalent circuit we will calculate the phase difference and based on that load torque is estimated for controlling the speed of induction motor.
For calculating the phase difference an equivalent circuit is designed. The power factor is the most important factor for estimating the rotor speed. From the measured values we can assume the relation between phase difference between and the torque. Here the phase difference is converted into time difference for estimating the torque characteristics on a digital counter. Here a L type equivalent circuit is built for calculating the phase difference.
By calculating the phase difference for stator currents we will control the speed of motor. As the load torque changes the rotational speed of motor also changes so a microprocessor is used for calculating the load torque values so as to maintain a constant speed. Here a control circuit performs the respective operations for maintaining the constant speed of induction motor. The tests are performed to check the accuracy of the circuit, different load torque conditions are applied and values are compared to see the changes for different operating frequencies.
The induction motors are extensively used in various house hold devices like refrigerators and air conditioners and also in industrial devices. This is cost effective device for controlling the speed of induction motors.
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