Though supply voltage distortion is generally measured using Total Harmonic Distortion (THD), the response of voltage distortion on Adjustable Speed Drive (ASD) loads does not show a proper correlation with this measuring index, THD. It is due to the fact that the response not only depends on the harmonic magnitude alone, also the angle of harmonics changes the response. In order to address this issue, this paper proposes the use of Crest Factor (CF) and Asymmetry Factor (AF) of the supply voltage to assess the impact of supply voltage harmonics on dc bus capacitor and choke inductor. The paper focuses on the response of harmonics on the front end of the ASD. © 2019 IEEE.