IEEE 1095-2012 pdf download IEEE Guide for the Installation of Vertical Generators and Generator/Motors for Hydroelectric Applications
5.2 Stator construction
The stator frame is typically fabricated from steel plate. Small-diameter stators can be shipped in one piecewith the core stacked and the winding installed at the factory. Larger-diameler stators are sectionalized forshipping purposes, the number of sections depending upon shipping limitations, and the sections bolted orwelded together at the site.
The sections may be stacked and wound at the factory or at the site, depending on preference or siterequirements. If wound at the factory. the coils or bars adjacent to the splits may be shipped separately andthe winding completed at site.
Soleplates, which may have provision for leveling and centering, are grouted into the foundation. On largerdiameters. provision is made to perit movement between the frame and the soleplates to accommodatethermal effects (typical in radial direction). Flexible stator pillars that handle the thermally induced forcesmay also be a design option.
The stator core is composed of electrical grade steel laminations treated with insulating enamel and stackedon keybars or core studs attached to the frame. The laminations are clamped in place by means of fingerand flange assemblies, with the required clamping pressure applied and maintained with core studs.
The stator winding may consist of single- or multi-turn coils or half-turn bars. Double-layer windingshaving two coil sides per slot, are most commonly used. The coils or bars are secured in the stator slots bywedges driven in grooves located at the top of the slots and by side-packing provided separately orintegrally with the coil or bar, End windings are braced to restrain movement due to short circuits and toprevent possible downward movement of the stator coils or bars. Temperature detectors are generallyinstalled between coils in a selected number of slots to indicate the temperature of the winding duringoperation.
5.3 Rotor construction
The rotor consists of a rim, to which the field poles are connected, and a structural support assembly,termed the rotor “spider,” used to connect the rim to the shaft.
The rotor rim is almost always a laminated-type, built up of segmental steel laminations bolted together toform one or several homogeneous rings. For some very small (5 MVA-10 MVA), high-speed (1000 rpmand above) generators, the rim may be a solid steel ring. This rim is free to expand without constraint fromthe spider, but it is keyed to the spider periphery for torque transmission and centering. Often the rim isshrunk onto the spider to minimize the differential radial movement between the two structures. The rimcan float at some level above rated speed, but it may float below rated speed (floating rim). The field polesare attached to the rim by bolts studs dovetails or T-tails.