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 firing
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. |
