Speed control for 3 phase motor - introduces power supply rotation w.r.t. windings by stationary segmental collector bridged by rotatable phase segments

摘要

Appts. gives sub and super synchronous speed control to a three phase machine. The machine windings are connected to a stationary segmental collector which is bridged by rotatable phase segments. These in turn are supplied with power through slip-rings. With no phase segment rotation the machine runs at synchronous speed relative to the supply. Turning the segments against machine rotation reduces speed whilst movement with rotation increases speed with respect to the stationary synchronous value. Provided the relative motion is maintained the phase segments may be stationary and the windings rotating.