INPUT CHOKES Reduce supply harmonic distortion and protect Optidrive against harmful supply disturbances Most types of drive products create supply harmonic distortion owing to the configuration of the power input circuit. Input chokes are used to reduce the effects of the Optidrive upon supply harmonic distortion (see below). Input chokes are also used to protect the power input circuits of the Optidrive against voltage spikes which might originate from lightning strikes or other equipment on the same supply. Small power Optidrives are particularly susceptible to this on certain supplies where lightning occurs or if there are other power electronic devices which cause notching on the supply ie welders, dc drives etc. Input chokes are available for Optidrive size 1, 2 and 3. Optidrive sizes 4, 5 & 6 include 3 phase line chokes as part of the products basic design, this significantly improves the robustness of these products and is a key specification benefit. A range of input chokes for 12 pulse systems are available on request.