AC servomotor for e.g. electronic typewriter - has permanent magnet strips on cup rotor with stator assembled by laminations, brushes and commutators

摘要

An a.c. servomotor for drives of printers, magnetic memories and automation accessories consists of an annular stator (1), enclosed in end caps (2, 6) with bearings, and a rotor (3) in a shaft (4). The lower end cap (6) is connected to a ferro-magnetic core (5). The stator is assembled from a stack of laminations (7) with a multistrand exciter winding (8). The cup-shaped rotor (3) is attached with its bottom (10) to the drive shaft and is revolved in the air gap (9). It consists of thin steel sheet and carries many permanent magnet strips (11) with a high BH product, such as samarium-cobalt. This requires neither rotor windings nor commutators and brushes and is well suited for positioning drives.