Hmm, I'm wondering about the shorted turn...
- If on the rotor, then it might to be possible to feel it when rotating the motor by hand under low voltage DC, it should cause a 'notch' feeling. It would certainly cause the motor to slow down on mains though.
- If it's on a field winding, it would have the effect of weakening the field and cause the motor to over-speed, a bit like an unloaded series would motor runaway.
@todorp, did the motor behave strangely just before it failed?
It would certainly draw excess current either way though, which might blow the thermal fuse before visible overheating of the winding.
I agree, a mains test, preferably dim bulb style, is the only way to know for sure.