> The good part is there's no more brushes to wear out and no dry seal needed so the motor can now be oil cooled from the inside as well, but to me it raises th

> The good part is there's no more brushes to wear out and no dry seal needed so the motor can now be oil cooled from the inside as well, but to me it raises the big question about the power losses incurred by the energy that's transferred to the rotor via induction versus the previous direct contact via brushes and slip rings. Slip ringed motors can be perfectly oil cooler as well. And you will need oil seals and drains in under any circumstances you use oil cooling.