 The AC traction motors are powered through insulated-gate bipolar transistor (IGBT) control.As on the dual voltage Classes 19E and 20E, the main electric circuit is automatically selected in either AC or DC mode, based on the voltage of the overhead contact wire feeding the locomotive.To facilitate automatic trouble-free transition on the run, the locomotive is equipped with onboard voltage detectors, while the overhead wire is equipped with two wooden isolators and a length of neutral wire to separate the AC and DC feeds.