at you measure motor current and RPM, with a full load, in order to calculate motor slip (see chart) and properly size the drive.
Drive Too Small If the drive is not sized correctly, making a change in the field requires not only a drive change, but also changing the resistors in the dynamic braking circuit.
Drive Too Large While a drive that is larger than necessary will not typically create problems, there is no reason to buy a larger drive than you need.