That's an interesting point. It also implies much better efficiency at low speeds than most motors.

Given a few generations of better semiconductor, it could end up being very interesting for (railway mostly?) traction motors.

• Low speed high torque means you don't need a further reduction gearbox.

• Good performance near zero speeds mean you might not need to use braking at all aside from parking and emergencies.

• High voltages are already widely used and available - 1500VDC nominal is an older standard for metro trains; 3kVDC is common both for older overhead and as an intermediate DC bus voltage for AC overhead. Future semiconductor generations could allow direct use of 25kV overhead (~40kVDC rectified at maximum line level) without the need for an intermediate bus, assuming the dielectric fluid was good enough.