What is the effect of applying a variable frequency drive (VFD) to a motor?

Applying a variable frequency drive (VFD) to a motor primarily allows for the control of both the motor's speed and torque. The VFD achieves this by manipulating the frequency and voltage supplied to the motor.

When the frequency of the electrical supply is adjusted, the motor's speed changes accordingly. Since the speed of an AC motor is directly related to the frequency of the supply voltage, varying the frequency allows for precise control over how fast the motor operates. Moreover, by controlling the voltage along with frequency, the VFD also influences the torque output of the motor, enabling it to deliver the necessary torque across a range of speeds. This capability is essential in various applications, where varying load conditions may require different motor performance characteristics.

Other options present misconceptions; for instance, the idea that a VFD can only increase torque ignores the technology's ability to adjust both torque and speed collaboratively. Furthermore, stating that it has no effect on speed overlooks the fundamental operation of the VFD. Lastly, the notion that it reduces the motor's lifespan does not take into consideration the advancements in VFD technology that are designed to enhance motor efficiency and extend operational life under controlled conditions. Thus, option C accurately reflects the functional advantages of integrating a VFD with a motor