As the mechanical load increases on a squirrel cage induction motor, what happens to the torque and stator current?

When the mechanical load on a squirrel cage induction motor increases, the motor must draw more current to provide the additional torque required to overcome the load. This is due to the fundamental relationship between motor torque, current, and the motor’s operating conditions.

As torque is directly related to current in induction motors, an increase in load leads to an increase in the rotor slip, causing the motor to draw more stator current. The slip is the difference between the synchronous speed of the magnetic field and the actual speed of the rotor. As slip increases due to the higher mechanical load, the rotor experiences a greater induced current, which results in higher torque being generated to maintain the balance between the mechanical load and the motor output.

Therefore, with an increase in load, both the torque and the stator current increase to enable the motor to perform effectively under the new conditions. This relationship is critical for maintaining motor operation and is a foundational principle in understanding how induction motors respond to varying loads.