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What Is Bearing Electrical Corrosion? Why Is It Common in Electric Vehicles? How to Prevent It?
In recent years, a common term has appeared in the repair industry: bearing electrical corrosion.
Especially in new energy and hybrid vehicles, bearings show dense pits, burn marks, and noise even with low mileage – and standard bearings fail again soon after replacement. This article explains electrical corrosion thoroughly.
Simply put, electrical corrosion occurs when current generated by the motor shaft passes through the bearing and discharges between the raceway and rolling elements, burning tiny erosion pits.
Early symptoms: humming noise.

Later stages: increased wear, seizure, or even locking.


Why is it especially common in electric vehicles?

  1. High-voltage platforms: 400V and 800V systems produce stronger shaft current.
  2. High-speed motors: higher RPM intensifies electromagnetic field changes and induced current.
  3. High switching frequency of electronic controls: stray current from inverters easily passes through bearings.


Typical features of electrical corrosion

  • Noise becomes sharper as speed increases
  • Uniform tiny pits on raceway surfaces
  • Lubricating grease blackens, carbonizes, or shows discharge marks


Three effective solutions (key points for purchasing)

  1. Electrically insulated bearings: insulation coating on the outer ring to block current
  2. Hybrid ceramic bearings: ceramic balls provide complete insulation against electrical corrosion
  3. Grounding conductive structures: release current through conductive slip rings or grounding brushes


Warning:
Bearings for NEV drive motors and air conditioning compressors must use anti-corrosion special types.
Replacing them with standard bearings is a waste of time and money.

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