Machine Shop · Case Study

Southern States EV2 Bearing Refurbishment & Upgrade

Southern States rotating switch bearings tend to seize over time, leaving a switch inoperable, and in extreme cases putting substation technicians at risk when a manual operator is forced against a frozen bearing. After refurbishing these bearings many times, we've traced the failures to two root causes: the dissimilar metals used in the original build, and water intrusion from a poor seal design.

01, The Problem

Why the factory
bearing seizes.

On a typical 230 kV example the housing and shaft are steel while the lock nut is aluminum. Aluminum against steel corrodes and locks the assembly solid. A degraded felt seal then lets water in, accelerating the damage all the way into the bearing itself.

Example 230 kV bearing: steel housing, steel shaft, and an aluminum lock nut. Aluminum against steel corrodes and seizes the assembly in place.
Fig. 01Example 230 kV bearing: steel housing, steel shaft, and an aluminum lock nut. Aluminum against steel corrodes and seizes the assembly in place.
Bottom view with the lock nut removed, rust and pitting across the shaft, with corrosion along the outer edge of the bearing.
Fig. 02Bottom view with the lock nut removed, rust and pitting across the shaft, with corrosion along the outer edge of the bearing.
The original bottom seal: a stainless-steel shim over a felt gasket. The felt had degraded and was holding water against the bearing.
Fig. 03The original bottom seal: a stainless-steel shim over a felt gasket. The felt had degraded and was holding water against the bearing.
The shaft had to be pressed out with a 45-ton press. Its only protection was a zinc coating, note the heavy corrosion and deep pitting.
Fig. 04The shaft had to be pressed out with a 45-ton press. Its only protection was a zinc coating, note the heavy corrosion and deep pitting.
The bearings also required the 45-ton press to remove. Corrosion from the shaft migrated straight into the bearing.
Fig. 05The bearings also required the 45-ton press to remove. Corrosion from the shaft migrated straight into the bearing.
The damage reached the race, ball bearings, and cage, well past the point where the bearing can be reused.
Fig. 06The damage reached the race, ball bearings, and cage, well past the point where the bearing can be reused.

Rebuilt to outlast
the original.

Every bearing comes back as a standard refurbishment. For customers who want maximum service life, the enhanced upgrade adds full stainless internals, a rain shield, and field-serviceable grease.

EV2 switch bearing assembly cross-section showing SSC upgrade components: 316 stainless shaft, sealed bearings, Viton O-ring seals, rain shield, and brass lock nut
Included
Standard Refurbishment
  • →Disassemble and thoroughly clean every reusable part, typically only the cast-steel housing is reused.
  • →Replace the bearings with comparable sealed bearings.
  • →Replace the steel shaft with a new stainless-steel shaft.
  • →Replace the aluminum lock nut with a brass lock nut that will not seize in place.
  • →Replace the felt seals with Viton O-rings, resistant to water and UV, with a better seal for the housing.
Upgrade option
Enhanced Refurbishment
  • →Upgrade the sealed bearings to 100% stainless steel.
  • →Add a machined aluminum rain shield beneath the mounting flange.
  • →Pack the housing with Mobil XHP222 grease.
  • →Add a zerk fitting so the grease can be replenished in the field.

The finished
bearing.

Rebuilt assembly: a stainless-steel shaft with the machined aluminum rain shield press-fit to the base. A Viton O-ring replaces the OEM felt seal.
Fig. 07Rebuilt assembly: a stainless-steel shaft with the machined aluminum rain shield press-fit to the base. A Viton O-ring replaces the OEM felt seal.
Detail of the layered seal, the Viton O-ring with a machined stainless washer set over it to provide a second barrier against water.
Fig. 08Detail of the layered seal, the Viton O-ring with a machined stainless washer set over it to provide a second barrier against water.
Machined brass lock nut and Viton O-ring alongside the rebuilt shaft. Standard steel bearings are replaced with sealed stainless-steel bearings.
Fig. 09Machined brass lock nut and Viton O-ring alongside the rebuilt shaft. Standard steel bearings are replaced with sealed stainless-steel bearings.
Mounting orientation. The machined aluminum rain shield directs water away from the shaft. Optional per customer spec: housing painted red for easy field identification.
Fig. 10Mounting orientation. The machined aluminum rain shield directs water away from the shaft. Optional per customer spec: housing painted red for easy field identification.
Bottom view, brass lock nut with locking cotter pin, stainless washer, and the added zerk fitting. Bearings and housing are packed with Mobil XHP222 grease.
Fig. 11Bottom view, brass lock nut with locking cotter pin, stainless washer, and the added zerk fitting. Bearings and housing are packed with Mobil XHP222 grease.
Have seized Southern States bearings?

Send us your bearings, we'll refurbish or upgrade them and return them ready to outlast the originals.

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