Should you specify an “inverter duty,” “inverter ready,” “inverter rated,” or a “VFD compatible” motor for your fans and pumps in HVAC applications? Is there a difference in these terms? Don’t answer ...

Increasingly common, variable frequency drives (VFDs) are used to control motor speed — elevating the frequency of power pulses/sec fed to motors for faster turning, and decreasing that frequency to ...

A VFD reports a low-volts fault when the drive's dc link voltage drops below 62% of the nominal level for the high setting (480 Vac) and 50% of nominal for the low setting (400 Vac). The +10% and -15% ...

This is the second half of a two-part article discussing principles and application of the AC induction motors that provide motive power for most of the equipment HVACR engineers specify. In March, we ...

Although much has been published on variable-frequency drives (VFDs), people continue to be confused by them. The intent of this article is to provide a basic overview of these devices by evaluating ...