Generator Stator Rewedging

Generator Stator winding

Stator wedges

Stator core

Thin Layer Electrical Metal Steel

General info on stator core

The stator core has an internal diameter of 4630 mm and a length of 2250 mm. It is
built up from segmental laminations punched from high grade, cold reduced, electrical
sheet steel, which are held in the frame by dovetailed keybars. The laminations are
divided into 59 layers (packets) formed by narrow steel spacers which provide
ventilating ducts leading from the stator bore to the periphery of the core.

Stator winding

The stator winding is of the double layer lap type, each layer comprising 64
conductors (32 deep by 2 wide) and each conductor being 2.24 mm x 5.8 mm glass
laminate covered copper strip. The conductors are transposed within the slot length
to inhibit circulating currents between

Stator wedge plate layers.


The two layers (bars) are wound and packed into the open core slots. The top and
bottom bars are spaced apart by a separator and retained in the slots by wedges

Dry ice blasting on the stator

Dry ice blasting on the stator

Dry ice blasting is a form of abrasive blasting, where dry ice, the solid form of carbon dioxide, is accelerated in a pressurized air stream and directed at a surface in order to clean it. Dry ice blasting leaves no chemical residue as dry ice sublimates at room temperature.

Objective: To remove dirt and unwanted contaminants on the stator core. This process also removes the varnish stain on the stator core.

Working principles:

Dry ice blasting machine

Dry ice blasting is a form of abrasive blasting, where dry ice, the solid form of carbon dioxide, is accelerated in a pressurized air stream and directed at a surface in order to clean it. Dry ice blasting leaves no chemical residue as dry ice sublimates at room temperature.

Dry ice blasting involves propelling pellets at extremely high speeds. The actual dry ice pellets are quite soft, and very less dense. Upon impact, the pellet sublimates almost immediately, transferring minimal kinetic energy to the surface on impact and producing minimal abrasion.

Dry ice blasting - air compressor

The sublimation process absorbs a large volume of heat from the surface, producing shear stresses due to thermal shock. This is assumed to improve cleaning as the top layer of dirt or contaminant is expected to transfer more heat than the underlying substrate and flake off more easily. The efficiency and effectiveness of this process depends on the thermal conductivity of the substrate and contaminant.