The Siemens Simodrive PW-Modul INT/EXT (typically part number 6SN1113-1AB01-0BA1 or 6SN1113-1AB01-0BA0) is a pulsed resistor (braking resistor) module for the Simodrive 611 drive system. It protects the DC link from dangerous overvoltages generated during motor deceleration.