Servo Motor also known as Control Motor. They have high torque capabilities. They are not used for energy conversion but their basic principle of operation is the same as that of other electromagnetic motors. But, their construction and design and mode of operation are different. Their power rating vary from a fraction of watt upto few 100 watt. Servo motor have low inertia, due to low inertia , they have high speed response, For that they are smaller in diameter but longer in length. Generally servo motor operates at very low speed or sometimes zero speed. Continue reading “SERVO MOTOR”
This motor name stepper motor as because this motor rotates through a fixed angular step in response to each input pulse receive by the controller. For growth of computer industries stepper motor demand also increased. Their polarity is due to fact that they can be controlled by computer, microprocessors. Continue reading “STEPPER MOTOR”
COGGING & MAGNETIC LOCK
SQUIRREL CAGE motor sometime s could not be start, the rotor of squirrel cage motor refuse to start at all, particularly when the voltage is low. This happen due to Magnetic Locking between stator and rotor teeth, when number of stator teeth is equal to number of rotor teeth.
For that Kind of reason sometimes this phenomenon is call TEETH LOCKING.
It is found that the reluctance of the magnetic path is minimum when the stator and rotor teeth face to face each other rather than when teeth of one element (rotor or stator) are opposite to the slots on the other. It is in such position of minimum reluctance, that the rotor tends to remain fixed and for that cause serious trouble during starting.
How to overcome from COGGING:
Cogging of squirrel cage motors can easily overcome by making the number of rotor slot prime to the number of stator slots.
Testing of Circuit Breaker is not so easy as other equipment such as Transformer, Motor, Generator etc. As short circuit current is very large for Circuit Breaker testing of these is difficult. Also there is no satisfactory methods to do it at reduce power. Continue reading “Circuit Breaker Testing”