"Waterproof Cooling Fan" trapezoidal wave sinusoidal EMF and EMF induction motor can reach peak are restricted invert DC voltage. In this case, if we assume that the peak value "Waterproof Cooling Fan" DC motor and the induction motor current is equal to the power output of the former is 33% higher than the latter, that is, the same "Waterproof Cooling Fan" rectifier / reverse change can drive 33% higher than the output power of induction motor brush less DC motor.