Ok, so been reading up on types of controllers, and It looks like the control board is using some form of TRIAC (TRIode for Alternating Current) or SCR (Silicon Controlled Rectifier) to provide the pulse width modulated DC duty cycle to the motor. In effect, it's taking the 60Hz AC and rectifying it into 60Hz DC current pulses of a width varied by the sliding potentiometer.
Due to the fact that these controllers use relatively low frequency pulse modulation, a motor connected directly to the controller would end up with very jittery operation and thus it needs the inductor or choke to smooth this out. Inductors resist changes in current flow and will store the pulses in the form of a magnetic field. So the choke is also a must if I want smooth torque at low speeds and will help ease the strain on the motor.
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