Effect of Rotor Resistance on Torque-Slip Curve
By increasing the rotor resistance in a slip ring induction motor alters the torque slip curve .The maximum torque produced by the motor remains unaffected by the rotor resistance but is inversely proportional to the rotor standstill reactance. As a result adjusting the rotor resistance modifies the slip value at which maximum torque is reached. When rotor resistance increases , the slip at which maximum torque occurs also increases.
With greater rotor resistance ,the curve shifts to the right , indicating a higher slip value at which maximum torque is achieved. This occurs because higher rotor resistance reduces the rotor current , which in turn reduces the slip required to develop maximum torque. As a result , the motor operates closer to synchronous speed for higher rotor resistances .
S = R2 / X2s
The above torque slip curves are drawn by keeping rotor reactance X2s constant for various values of rotor resistance R2 .
When R2 is 0.1 times of X2 , the maximum torque will occur at slip
S = R2 /X2s = 0.1 X2s / X2s = 0.1
Now , if we increase the rotor resistance value by adding some external resistance then the maximum torque would occur at a slip is also changes.
Torque Slip Characteristics of Induction Motor
The torque slip characteristics of an induction motor is a plot that shows the relationship between the torque produced by the motor and the slip. Where slip is the difference between the speed of the rotating magnetic field produced by the stator and rotor speed. The torque slip characteristics are essential for optimizing the motor’s performance. The torque slip curve provides essential characteristics of the motor including its capabilities, efficiency and also operating range.
It is used to design and analyze motor systems for various applications. These are used in applications where high starting torque and high pull-up torque are required. It is used to predict motor behavioral characteristics under different load conditions and facilitates the design of control strategies to enhance performance.
Here in this article, we will discuss the definition of torque slip characteristics, torque slip characteristics in three-phase induction motors as well as single-phase induction motors, the effect of rotor resistance on torque-slip curve, advantages, disadvantages and applications of induction motors.
Table of Content
- Torque Slip Characteristics?
- Single-Phase Induction Motor
- Three Phase Induction Motor
- Effect of Rotor Resistance
- Advantages
- Disadvantages
- Applications