Quote Originally Posted by smoothops10 View Post
Golddigger you are correct but real power is not a constant in this scenario. Let's use what the mfr gives us: a drive efficiency of 97.5%. Drive pf of 0.97 to 0.98. Let's assume a motor pf ranging anywhere from .8 to .93. Using these in any range of the motor pf, the drive power, real or apparent, never meets or exceeds the motor power. I have a spreadsheet I can post tomorrow I used to check this but I still feel drive is undersized albeit only a little but the point remains.
For a variable frequency drive, the input kVA is almost invariably lower than the output kVA at rated load.
It's simply a result of the lower output power factor. Nothing more complicated than that.