H-M Supporter Gold Member
- Jun 12, 2014
It is my understanding that the bearings are the same, so it is not necessarily a mechanical limitation. There may be some limitations as to developing full horsepower out to 2X rated speed and torque can fall off in a somewhat more non-linear manner above 1.5X base speed. A lot depends on the motor specs, so motors like the Marathon BlueMax and BLackMax 3 phase 1750 RPM motors are rated up to 5-6K. Most of the better built 3 phase motors are OK up to 2X base speed. Just wouldn't push the motor hard for long periods at the higher RPM.