Linear motor writing unit for recording potentiometer - has magnetic circuit with air gap in which carriage coil can slide

摘要

A carriage sliding on rails carries a driving coil surrounding a bar-shaped rectangular soft iron core. One of coil sides slides in an air-gap between the soft iron core and a permanent magnet. The carriage sliding transversally to the chart movement carries a pen and the recorder compensation circuit position signalling element. The air gap (1c) between bar-shaped soft iron core (1a) and also bar-shaped permanent magnet (1b) corresponds in shape and size to the iron core (1a) which, together with a bar-shaped yoke (1d) and two yoke limbs (1e, 1f), forms a magnetic circuit surroundings the permanent magnet (1a). Its total height is smaller than the width of the air-gap (1c), which in turn is smaller than its length. The carriage (2) bridges the magnetic circuit.