Frequency converters are power supplies that control the electric current fed to motors and rotors to modulate their speed. Increase the frequency of the drive and the speed of the motor increases. The 9500h ID was for a frequency converter made by a company named Vacon in Finland; the 7050h ID was an unspecified model of converter made by a company named Fararo Paya in Iran. O’Murchu suspected the Fararo Paya converters were an Iranian knock-off of the Finnish one.4 If this was the case, there was likely no other facility outside of Iran that used the converters from Fararo Paya.
