>> > You can also do this with DC motors, it's called field weakening. >> >> Or, a series motor with a light load. No-load, they will run so fast >> that they can self-destruct! > >Apply 100V to a DC motor with no load, it will do x RPM. >Apply 200V to it, and it will do 2x RPM.
If you apply 100V DC to a typical series wound traction motor, without a load, it will accelerate and continue to accelerate until it reaches the self-disassembly point. There is no "x RPM" for a series wound motor. Applying 200V won't make it spin twice as fast because it's already in pieces from applying 100V. FWIW applying a low voltage, say 12V, might not cause this to happen because at some point the friction/windage will be enough of a load to balance the input power and acceleration stops.
