Electric Discharge


Electric discharge wear on gear teeth. Photo courtesy GEARTECH © 2014.

Definition: Electric discharge is a form of damage caused by electric arc discharge across the oil film between active gear or bearing contact surfaces.

Identification: Electric discharge results in the formation of pits on the damaged surface. SEM shows small hemispherical craters and melted steel spheres.

Discussion: Electric discharge can cause severe damage to gear and bearing contact surfaces.

Prevention: Use good insulation and grounding practices. Avoid welding near gearboxes.

More Information: For more information on electric discharge damage, please submit a question to our “Ask an Expert” link. For assistance with a gearbox failure analysis, please visit our “Consulting” page.