It is normal to have output current larger than the input current and power efficiency will always be lower than 100%. The structure below is an AC motor drive connected to an induction motor. The motor is an inductive load (voltage leads current) which results in reactive current at the AC motor output side and leads to a lower power factor and larger apparent current. The capacitor inside the AC motor drive is a power storage unit that makes the AC motor drive a capacitive load (current leads voltage). The diagram below shows the AC motor drive and the motor are a system that combines capacitive and inductive loads. It indicates that the power factor at the AC motor drive input side is higher than the output side and results in apparent current that is lower at the input side than the output side. The power efficiency equation is a calculation of active current. As the active current of AC motor drives at the output side is always lower than the input side, from the equation below it clearly indicates that power efficiency will always be lower than 100%. Power Efficiency Equation