Revealing the Real Story Behind Motor Power and VFD Ratings: Avoid Costly Mistakes
When it comes to selecting a VFD for a motor, many professionals start with the values provided for Normal Duty (ND) and Heavy Duty (HD). It seems straightforward — these ratings supposedly help match a drive to a motor based on its operating cycle. But here’s the truth: these numbers can be misleading. In fact, the Heavy Duty rating is essentially a derated version of the VFD’s Normal Duty value.

