Thanks for all your responses. I have some more info that might make a difference. This is a completely new installation. There are numerous fans where this is taking place. The new info is two plug fans, each 37500 CFM for a total supply CFM of 75000, at 41.64 BHP each with 50 HP and 900...
Is it common practice to operate a motor above it rated RPM using a VFD? The fan is a direct drive with a 900 RPM motor. The design fan RPM is 1,250 and the vendor wants to operate the motor at 1,250 using the VFD.
Is it common practice to operate a motor above it rated nampeplate RPM using a VFD? The direct drive fan has a 900 RPM motor but the design fan RPM is 1,250 RPM. The vendor is saying you can use the VFD to operate the fan at design RPM.