Using a transformer with a motor
You don't get to set the voltage and current of a load at the same time.

What you propose might give a higher unloaded motor speed, since the motor will draw little current then.  As the motor gets more loaded, eventually it will try to draw more current than the transformer can supply, which will cause the motor to stall.  At that point, the voltage collapses too.

Basically, what you are really asking is how a motor behaves with a high voltage but high impedance supply.

Of course all this is only valid if the motor can run on AC.  Some can, others can't.