Variable frequency drives (VFDs) have become very common in the industrial space and can improve your operations tremendously. However, they come with occasional challenges and potential downsides that can affect applications.
VFDs control the rotational speed of alternating current electric motors by adjusting the frequency and voltage applied. Basically, this is done by switching IGBT output devices. For example, fan, pump, and air compressor applications use VFDs and account for more than half of the electricity consumed by U.S. industrial operations.
Although equipment can generally operate at less-than-maximum velocities of their connected motors without VFDs, this isn’t possible without using throttling devices such as valves, dampers, or bypasses. Therefore, a VFD provides an efficient way to control varying flow rates and pressures.
If you don’t think a VFD is the right choice for your application, some alternatives may be better suited for your environment. For example, across-the-line starting does not control speed and allows for full-torque starting and stopping. Additionally, soft starting methods do not control speed but allow for smooth starting and stopping.