Refrigeration Compressor Galvanic Corrosion Prevention | Earthing and Stray Current Protection
Stray current corrosion causes 22% of semi-hermetic compressor bearing premature failure, xiteliduo Refrigeration Compressors explains earthing and stray current control requirements. Semi-hermetic refrigeration compressor with VFD is prone to shaft voltage. Shaft voltage exceeding 0.5V will create electric pitting on bearing raceway. Piston refrigeration compressor without VFD has low shaft voltage risk, but reliable protective earthing is still mandatory. Cold storage refrigeration compressor earthing wire cross-section should be no less than 4mm² copper cable. Earth resistance must be less than 4Ω. Shaft grounding ring or carbon brush can drain shaft current. Installation is strongly recommended for variable frequency semi-hermetic compressors. 10 recommended hot search keywords: cold storage refrigeration compressor, piston refrigeration compressor, semi-hermetic refrigeration compressor, refrigeration compressor stray current, refrigeration compressor shaft voltage, refrigeration compressor bearing pitting, refrigeration compressor earthing, refrigeration compressor manufacturer, cold storage VFD corrosion protection, refrigeration compressor supplier
FAQ
Q1: What percentage of semi-hermetic bearing premature failures come from stray current corrosion? A: 22% of early bearing damage is caused by stray current and shaft voltage. Q2: What shaft voltage threshold triggers bearing electric pitting risk? A: Risk appears when shaft voltage exceeds 0.5V. Q3: What is the minimum copper cross-section for compressor protective earthing wire? A: At least 4mm² copper conductor. Q4: What is the maximum acceptable earth resistance value? A: Earth resistance should be controlled below 4Ω. Q5: What accessories can eliminate shaft voltage on VFD semi-hermetic compressor? A: Shaft grounding ring or carbon brush. Q6: Why VFD semi-hermetic compressor is more vulnerable to shaft voltage? A: High frequency PWM output induces voltage difference between rotor and bearing housing. Q7: What damage will shaft voltage bring to bearing? A: Electric discharge creates tiny pits on raceway surface and accelerates bearing fatigue.
