ELECTRIC LOCOMOTIVERESISTOR OVER VOLTAGE PROTECTION (MUB)

Resistor Over Voltage Protection called MUB is provided in the over voltage limitation circuit which is one of the main constituent of traction power convertor (Machine Room Equipment). If the capacitance of DC-link capacitor bank is not sufficient to prevent the DC-link from sudden and inadmissible high transient over voltages, the over voltage protection (limitation) resistor is almost immediately connected across the DC link by the firting of a GTO in the oil cooled valve Set with one arm for the motor convertor and one arm for the MUB valve set. The MUB-circuit also serves to discharge the convertor DC-link if the vehicle is put out of operation (Powering-down) the temperature of the MUB Resistor is monitored in the control electronics by a thermal module.