I suggested a 1μF capacitor in #11. Nice to know my guess was reasonable.
I also suggested that the switch could operate in the reverse direction. This is due to the supply to the motor being changed from constant voltage to constant current, defined by the capacitor.
With the voltage supply, the higher the impedance of the motor, the less the power.
With the current supply, the higher the impedance of the motor, the more the power.
The impedance looks to be changed by changing the number of turns in the coil.