The AC input voltage of the SX drive should not exceed 132 VAC. There are a few reasons for this. If the buss voltage is too high we may activate the regen circuit. When the regen circuit activates the drive starts dumping the excess power to an internal resistor which could over heat and cause damage to the drive. Another reason is that the AC input circuits (i.e. Fuses, resistors, rectifier) are designed for a maximum of 132 VAC. Using a higher input voltage may cause internal damage to that circuit.