Motor control system for sewing machine
US4161919A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 7, 1977 |
| Grant date | Jul 24, 1979 |
| Priority date | — |
| Expiry date | Jul 7, 1997 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P7/293
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A motor control system for sewing a machine is disclosed in which motor drive thyristors, a trigger phase control circuit for the thyristors to control motor speed, and a dynamic brake control circuit means are employed. The dynamic brake control circuit means includes a shunt thyristor connected in parallel with the armature winding of the motor, and a brake command circuit which triggers the shunt thyristor so as to stop the motor by dynamic braking force. The brake command circuit is energized and triggers the shunt thyristor when a stop command signal and a deceleration detection signal are supplied. Thus dynamic braking of the motor of a sewing machine can be accomplished at a predetermined lower speed. To use the motor as a dynamo for dynamic braking stop control of the motor, a trigger phase clamp circuit is employed. To stop the motor at predetermined halt positions, a timer circuit, a predetermined constant trigger phase command signal generator circuit, and needle position detectors are employed. The timer circuit is energized by the stop command signal and generates a signal in a predetermined time interval, by which the generator circuit is energized and controls the tr…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.