Manchester Metrolink-vehicle propulsion and auxiliary system

The two car articulated Metrolink vehicles are powered by four separately excited DC traction motors. The motors are arranged in a two series two parallel configuration, each series armature string being controlled by an independent chopper. The vehicle HV auxiliary loads-the heating and compressor circuits are fed directly from the line at 750 V. The LV auxiliary loads-the vehicle control circuit, lighting circuits and track brake magnets are supplied from a static auxiliary converter. The auxiliary converter also supplies the motor field circuits. The propulsion and auxiliary systems use the latest control technologies applied to a proven power system. The propulsion and auxiliary converters are microprocessor controlled and use gate turn off thyristors (GTOs) in the power circuit. The auxiliary converter also uses insulated gate bipolar transistors (IGBTs) in its outputs which offer advantages for lower power switching applications