Silver Arc Sphere
This is a silver arc sphere from a sample of transformer oil. This may have been from a silver plated contact in a circuit breaker or load tap changer whose oil became mixed with the oil in the transformer.
Transmitted Off Crossed Circular Polarized Light and Reflected Darkfield Illumination
Definition/Function:
Silver arcing spheres are generated when an arc is discharged in the transformer under the cover of oil. It is the result of molten silver being formed by the arc and ejected into the oil by the rapid thermal expansion of the metal under the molten metal. The size of the arc particle is an indication of the strength of the arc.
Significance in the Environment:
There is some arcing to a silver surface going on in this transformer or there has been some mixing of oil from a circuit breaker or load tap changer compartment.
