Input chokes can be used to reduce the supply line harmonic currents and voltage distortion generated by almost all inverter drives on the market today. Invertek Drives have selected a range of chokes matched to the Optidrive range to provide the best reduction in supply current harmonics whilst also providing enhanced protection for the Optidrive against transient voltage spikes or other mains-borne interference. Input chokes are available for the complete range of Optidrive products and are recommended for use in all installations, and in particular: - Where the local mains supply quality may be poor or unknown - Where high current switching loads such as large DC drives or soft starts are operating - Where the mains supply impedance is low - In remote areas prone to lightning strikes