What do VFDs primarily control to ensure the operation of electric motors?

Variable Frequency Drives (VFDs) primarily control the speed of electric motors by varying the frequency and voltage supplied to the motor. The speed of an electric motor is directly related to the frequency of the electrical supply; increasing the frequency increases the speed, while decreasing the frequency reduces the speed. This ability to precisely adjust the speed allows for efficient motor control in various applications, improving performance and energy efficiency.

While VFDs can influence current and torque indirectly by changing the speed and load conditions, their main function is to modulate the frequency of the power supply, thereby controlling the motor's speed effectively. This capability is essential in applications requiring variable speed operation, such as in pumps, fans, and conveyors, where operational efficiency and process control are paramount.