Patent ID: 8421399

Claim:
A power control system for an A.C. induction motor, comprising: a voltage/current phase difference generator for determining a difference in phase between a voltage applied to the motor and a current drawn by the motor, and for generating a phase difference signal as a function of the determined difference in phase, the voltage/current phase difference generator including an integrator, the integrator receiving the phase difference signal and generating an error signal for controlling an amount of power supplied to the motor as a function of the phase difference signal, the integrator being electrically coupled to a potentiometer, the potentiometer providing a bias signal for at least partially controlling the error signal; and a delay circuit for controlling the bias signal provided by the potentiometer so as to cause full available power to be supplied to the motor for a predetermined amount of time, wherein the potentiometer further comprises first and second outer terminals and a center tap terminal, the center tap terminal providing the bias signal, wherein the delay circuit controls the resistance appearing across the first outer terminal and second outer terminal of the potentiometer for the predetermined amount of time, and wherein the delay circuit further comprises: a DC power supply having a DC supply voltage derived from an alternating current source; a delay timer having an input for receiving the DC supply voltage from the DC power supply and an output for outputting at least a portion of the DC supply voltage for the predetermined amount of time; a comparator having an input, the input of the comparator being electrically connected to the output of the delay timer, the comparator being configured to operate in a low state for the predetermined amount of time after receiving the at least a portion of the DC supply voltage from the delay timer and to operate in a high state thereafter; and a relay having a drive coil and a pair of output contacts, the drive coil being in electrical communication with and driven by the comparator, the output contacts being in a closed state across the first and second outer terminals of the potentiometer when the comparator is in the low state and being in an open state otherwise.