Torque speed relationship of induction motor

Starting torque is the torque produced by induction motor when it is started. We know that at start the rotor speed , N is zero. So, the equation of starting torque is easily obtained by simply putting the value of s = in the equation of torque of the three phase induction motor , The starting torque is also known as standstill torque . Torque Slip Characteristics of Induction Motor.

The torque slip curve for an induction motor gives us the information about the variation of torque with the slip.

Multiple solutions of the above equation for torque at different slips can be made simpler by simplifying the equivalent circuit model.

Torque Equation of Three Phase Induction Motor The equation for rotor current and torque in terms if rotor quantities and slip is and maximum torque occurs when.

Torque - equation -of-an- induction - motor -eq-The above equation expresses the developed torque directly in terms of the air gap power Pg and the synchronous speed ωs. Since ωs is constant and independent of the load conditions. If the value of the Pg is known then, the developed torque can be found directly. Induced Torque from Physical Standpoint (1) net. INDUCTION MOTOR TORQUE SPEED CHARACTERISTICS . Sketch the above characteristics of torque -slip ( speed ), explaining the various features.

Derive the expression of maximum torque and the slip ( speed ) at which it occurs. Draw the above characteristics with the variation in input (stator) voltage and rotor resistance. Speed - torque curves for four induction motor types: A) Single-phase, B) Polyphase cage, C) Polyphase cage deep bar, D) Polyphase double cage. The relation between torque and speed can be established by the given curves below: The torque of the induction motor is zero when the motor is driven slower than synchronous speed. NPTEL provides E-learning through online Web and Video courses various streams.

As the slip is less than this means that the speed of rotor is less than synchronous speed and the rotor is rotating in the direction of rotating magnetic field. Also, electromagnetic torque for this region of operation of induction motor is positive as clear from the characteristics and equation (1). The slope of this straight line depends mainly on the rotor resistance. Higher the resistance, sharper the slope. This linear relationship between torque and . This torque is related to the motor output power and the rotor speed and.

When the speed is very near to synchronous speed. The slip is very low and (sX 20) is negligible in comparison with R2. If Ris constant, the torque becomes.

Torque -slip- characteristics -of-an- induction - motor -eq-.