Speed control system of a motor and a circuit therefor

Abstract

Abstract THE INVENTION RELATES TO SYSTEMS FOR CONTROLLING THE SPEED OF A MOTOR AND CIRCUITS THEREFOR EMPLOYING SYMMETRICAL SEMICONDUCTOR SWITCHING ELEMENTS AND MORE SYMTICULARLY TO THE CIRCUITS OF RELATIVELY SIMPLE CONSTITUTION IN WHICH THE INPUT TERMINAL VOLTAGE OF THE MOTOR IS SUBJECT TO A SPACED WAVE CONTROL AT THE TIME OF LOW SPEED THEREOF SO AS HEIGHTEN THE LOW SPEED CONTROL OF A LOAD HAVING A FLUCTUATING TORQUE CHARACTERISTIC SUCH AS A SEWING MACHINE AND THE VOLTAGE IS MADE TO INSTANTLY RESPOND TO VARIATIONS IN THE LOAD OF THE MOTOR, AND THE MOTOR IS AUTOMATICALLY MAINTAINED AT A SET SPEED. FOR THIS PURPOSE, THERE IS PROVIDED A CONTROL CIRCUIT WHICH IS ADAPTED TO CONTROL THE CONDUCTION PHASE OF A SYMMETRICAL SEMICONDUCTOR SWITCHING ELEMENT FOR A MAIN CIRCUIT BY MEANS OF A SYMMETRICAL SEMICONDUCTOR SWITCHING FOR IGNITION THROUGH A PULSE TRANSFORMER. IN THIS CONTROL CIRCUIT, A VOLTAGE DIVIDING CIRCUIT HAVING A VARIABLE RESISTOR IS PROVIDED IN PARALLEL TO THE MAIN CIRCUIT AND AN IGNITION CIRCUIT INCLUDING THE SWITCHING ELEMENTS IS CONNECTED BETWEEN THE WIPER OF THE VARIABLE RESISTOR, THE PULSE TRANSFORMER AND THE MOTOR SO THAT THE DIFFERENTIAL VOLTAGE BETWEEN THE SET VOLTAGE DIVIDING CIRCUIT AND THE SPEED STARTING VOLTAGE OF THE MOTOR IS APPLIED TO THE SWITCHING ELEMENT FOR IGNITION, AND FURTHER A DIODE IS CONNECTED IN THE FORWARD DIRECTION TO THE VOLTAGE DIVIDING CIRCUIT FROIM BETWEEN THE PULSE TRANSFORMER AND THE MOTOR SO THAT THE VOLTAGE APPLIED TO THE TERMINALS OF THE SWITCHING ELEMENT FOR IGNITION BECOMES POSITIVELY AND NEGATIVELY ASYMMETRICAL TO MAKE THE SWITCHING FUNCTION OF THE SWITCHING ELEMENT PERFORM ONLY IN ONE DIRECTION.

Inventors

• 👤 Kenzi Kato

Bibliographic Details