Linear motor for typewriter carriage drive - has control time constants reduced using compensation coil to counteract effects of control loop measuring coil

摘要

The linear motor has its control time constants reduced by incorporating a compensation coil (8) in the same magnetic circuit as the measuring and drive coils (4, 5). The typewriter carriage is driven along two ferromagnetic plates by the drive coil which is mechanically coupled to the measuring coil. The measuring coil has a current induced in it that describes the carriage motion and is used for regulating the current in the drive coil. The compensation coil is coupled in series with either the drive or the measuring coils and has the opposite winding sense. The compensation coil counteracts the measuring coil effect on the carriage motion.