A shorting device (typically using thyristors) connected in shunt between the machine’s rotor and the rotor-side power converter. The crowbar may include some impedance in the shorting path. This option is illustrated in Figure 1
Shorting of the rotor via switching of the rotor-side power converter
A chopper circuit on the converter’s dc bus, to limit dc bus voltage by diversion of some or all of the current coming from the rotor is more often used in newer designs