CDR Current Diverter Rings

[bigalow]

What are they and what do they do?

[Al_The_Man]

These are basically intended to prevent currents induced or imposed on motor rotors that may leak to ground through the shaft bearings.
If this happens in any great degree, the bearing races and balls or rollers become pitted.
This used to be prevalent with commutator or slip ring fed armatures where a ground leakage occurred on the wound armature.
Now supposedly the same effect can occur on variable frequency drives, where high frequencies are induced in the rotor.
The diverter ring is supposed to by pass or shunt the current that would otherwise flow to ground through the bearing.
Al.