Solid state motor control system

A solid state timing control system for regulating the operating cycle of an electric motor which comprises:

• first normally non-conductive solid state switching means connected in series with said motor, said first solid state switching means precluding operation of said motor when in non-conductive state and effecting operation of said motor substantially at line voltage during entire operating cycle when in conductive state;
• a resistor and a first capacitor connected in series with said motor and in parallel with said first solid state switching means, the value of said resistor being selected to limit the current passing through said resistor-capacitor circuit to preclude operation of said motor;
• a second, voltage responsive solid state switching means connected between said first solid state switching means and the junction between said resistor and said first capacitor and rendering said first solid state switching means conductive in response to a predetermined voltage;
• bridge rectifier means having input terminals thereof connected across said first capacitor;
• a transistor having emitter and collector thereof connected across output terminals of said rectifier means;
• a bias circuit including an adjustable bias resistor connected in series with a Zener diode and a second capacitor connected in parallel with said adjustable bias resistor, either said transistor collector or emitter being connected to one side of said second resistor and said second capacitor, the base of said transistor being connected to the anode of said Zener diode, the other side of said second capacitor being connected to the junction of said resistor and said Zener diode through the normally closed contacts of a manually operated switch and to said emitter or collector not connected to said bias resistor through the normally open contacts of said manually operated switch;
• said bias circuit being operative to render said transistor conductive in response to the voltage across said first capacitor reaching a selected value less than a pre-selected value required to render said second voltage responsive solid state switching means conductive;
• said second capacitor charging in response to actuation of said manually operated switching means connecting said capacitor across said transistor collector and emitter and discharging through said adjustable bias resistor in response to de-actuation of said manually operated switching means for rendering said transistor non-conductive and connecting said capacitor across said adjustable bias resistor, thereby allowing the voltage across said first capacitor to increase to said pre-selected value to render said second voltage responsive solid state switching means conductive;
• said first solid state switching means being rendered conductive in response to said second solid state switching means being rendered conductive to effect operation of said motor for a selected time interval determined by the discharge time of said second capacitor.