Rotation control device for sewing machine motor

摘要

Machine has a sewing motor rotatable in both directions with electronic control, direction and speed detecting means. If, during the sewing of thick fabrics, the speed falls below a pre-set min value, a timer is activated. When this timer times out, the motor is reversed and/or repeated as set by the4 machine controller. The motor is alternately reversed at pre-set time intervals. Motor speed(Sj) is pref. detected in circuit (9b) and below a min. pre-set threshold value, the motor control circuit (7) reverses the motor rotation after a time(T). Motor is then alternated in both directions until the fabric is penetrated or the machine halts for manual intervention. The4 motor may be A.C., D.C series commutator or D.C. brushless type.