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Photographic gallery.  Thousands of particles under the microscope.
Particles from many different sources are found in transformer oil. These are just a few examples. The file that follows contains images of specific types of particles with reference to their source.

Particles From Transformer Oil Particles From Transformer Oil Particles From Transformer Oil Particles From Transformer Oil Welding

Magnetite Sphere Magnetite Sphere Weld Slag, Magnetite Blister Weld Slag, Magnetite Blister Weld Slag Magnetite Sphere

Grinding

Magnetic Manufacturing Residues Silicon Carbide Abrasive

Heat-Treat Scale



Iron Wear

Magnetic Manufacturing Residues Magnetic Manufacturing Residues Magnetic Manufacturing Residues

Bronze Wear

Bronze, Paint etc Bronze Gear Wear and Paint Bronze Gear Wear Bronze Wear

Copper Wear

Copper Wear Copper Wear

Paint

Paint Spheres Paint Spheres Red Paint Flake Layered Paint Flake Paint Spheres Paint Spheres Paint Flake

Gasket



Wood



Other

Iron Drill Turning Iron Drill Turning Glass Fiber Solder on Paint

New Paper Fiber

Paper Fiber Paper Fiber

Aged Paper Fiber

Degraded Paper Degraded Paper Degraded Paper Degraded Paper Lab Degraded Paper

Aged Paper

Degraded Paper Degraded Paper and Limonite Degraded Paper and Limonite

Charred Paper

Charred Paper Charred Paper Charred Paper and Gear Wear Charred Paper Charred Paper Charred Paper Charred Paper

Charred Wood

Charred Wood Charred Wood Charred Wood

Other Aged Cellulose

Degraded Wood Degraded Rayon Degraded Rayon Transformer Sludge Resin Sphere Resin Sphere Spherulites Spherulites Spherulites Copper Arc Sphere Etched Copper Arc Sphere Copper Arc Sphere Silver Arc Sphere Soot from Arced Oil Limonite Quartz Filler and Limonite Rust Degraded Paper and Limonite Limonite Gear Wear + Gear Wear Natural Minerals

Quartz Sand Grain Quartz Sand Grain Sand Grains Quartz and Hemetite

Pollens

Pollen Grains Pollen Grain Pollen Grain

Tire Wear

Tire Wear

Fungal Debris

Alternaria Spore Alternaria Spore Magnetite Sphere

Other

Sodium Chloride, Salt Charred Wood Spore, Starch, Tire Wear Alternaria Spore and Demisted Larva Hair Spores, Pollen, Natural Minerals, etc. Spores, Pollen, Natural Minerals, etc. Cenosphere

All of the particles that follow are from one 50 milliliter oil sample collected from a 8400 kVA Transformer. The transformer reportedly had a gas blanket and was sealed. The particles indicate otherwise. The large number of degraded paper fibers in this sample indicate severe degradation of the paper insulation and there is evidence of charring of the paper at some locations.

Diatomaceous Earth Diatomaceous Earth Degraded Paper Degraded Paper Degraded Paper Natural Minerals Natural Minerals Feldspar Copper Abrasive Wear Contact Wear Contact Wear Charred Paper Charred Paper Coke Mixed Particles Polymer Flake Paint Flake Silver Scuffing Wear Silicon Carbide Corn Starch