Impact of Cable Connection Length on Harmonic Distortion

February 17, 2021

The Problem With Cable Length

Long cables increase harmonic distortion for the overall motor drive system (figure 1). CTM discovered the effect of cable lengths on harmonic distortion through customer provided field data. Due to the additional noise generated from the cables, CTM recommends purchasing an integrated panel package type because it reduces the length of the inductor to capacitor connection cables (figure 2).

There are additional cabling factors that impact the performance of your filter. These factors include cable length, gauge, insulation ratings, and system frequency. If these factors aren’t taken into consideration, premature failure or severely reduced system performance can occur. When selecting cable connections, CTM recommends following table 1 below. The information in this table came from the National Electrical Code’s guidelines on allowable ampacities of insulated conductors. Additionally, CTM recommends using the shortest possible cable connections to reduce the total harmonic distortion of the system.

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