I guess you have to play with magnetic forces rather than playing with electric ones in that case.
Play with starting inductance values if such exists or try to play with two-pole magnet either increasing or decreasing a magnetic field arround the motor. If the motor is magnetically shielded you maynot get a desirable result
Play with starting inductance values if such exists or try to play with two-pole magnet either increasing or decreasing a magnetic field arround the motor. If the motor is magnetically shielded you maynot get a desirable result