Fully slotless turbogenerators

Abstract

The constraints restricting the choice of rotor length and diameter in a turbogenerator are relaxed, and much higher airgap flux densities are possible if a fully slotless construction is employed. Capacities about three times greater than can be achieved with conventional machines are possible, and there is wide scope for optimising the dimensions and loadings of machines of present -day ratings; e.g. a 660 MW slotless machine could show savings of about 2 MW in losses, 4 m in length and 150 t in mass and would have reactances more suited to stable operation. Gas or liquid cooling of the active parts could be employed without special problems.