Field Services

Repairs, Fluid Purification, and Installations Repairs

Repairs extend the life and improve the reliability of transformers, circuit breakers, switches, and other high-voltage equipment. TSI has broad field and shop repair capability. Services provided include: Transformers, Voltage Class Thru 765KV

  • Cleaning or replacing bushings and insulators
  • Replacing pumps, coolers, fans, and radiator assemblies
  • Re-gasketing
  • Replacing gauges
  • Internal inspection and repairs
  • Load Tap Changer servicing
  • Testing: Power Factor, Dielectric absorption, Transformer Turns Ratio, Insulation, and Winding Resistance
  • Painting on-site
  • Transformer reconditioning
  • Adding AGE inhibitor to perchloroethylene (“perc”) based fluids (Wecosol, System 50, Transclene)
Transformer Service Inc.

Circuit Breakers, Low Voltage 600 Volt Class

  • Circuit breaker disassembly, cleaning, lubrication, exercising, and re-setting
  • Upgrades to electronic trip units
  • Circuit breaker primary and secondary injection test; Ductor test

Fluid Purification

TSI has been an industry leader in transformer oil treatment since 1952. TSI has three truck-mounted oil purification systems that provide the following treatment of 10c mineral oil, cable oil, Rtemp, and bio-fluids:

  • Re-refining to remove acids and particulate material
  • Dehydrating to remove free and dissolved water, including insulation dry-out of the windings
  • Degassing to remove other dissolved combustible gases such as Acetylene, Ethylene, Ethane, Methane, Hydrogen, Carbon Monoxide, and Carbon Dioxide
  • Adding of BHT oxidation inhibitor to oil-filled transformers

Most transformers can be processed while energized provided there is adequate clearance from bushings and safe access to fill and drain valves.

TSI’s process uses inline moisture monitoring, on-site dielectric tests, and fluid quality tests for process control.

TSI also has portable equipment to degas and dehydrate silicone-filled transformers.

Transformer Service Inc.
Transformer Service Inc.


Vacuum Fills and On-Site Dry-Out

TSI’s vacuum fill process ensures that a new transformer is thoroughly dehydrated prior to being put into service. The steps in the vacuum fill process are:

  • A pressure test to ensure the vacuum integrity of the transformer
  • A 24-hour (or other time as directed by the customer) vacuum hold at less than 1 mm to draw moisture from the core and coil
  • If desired, the transformer may be filled with dry Nitrogen and held under pressure for 12 to 24 hours to allow a dew point test to be performed to verify that the desired moisture level has been achieved.
  • If desired, the oil can be dehydrated while in tank trailers prior to filling.
  • The oil is passed through TSI’s dehydration system where it is further heated and vacuum dehydrated.
  • The transformer is kept under a vacuum while it is being filled slowly with hot oil. This evaporates additional residual moisture.
  • If desired, the vacuum may be held for several hours after the oil fill is completed.
  • On-site dry-out is accomplished by circulating hot oil while the transformer is under vacuum. A cold trap is used to measure the amount of moisture removed from the transformer.
Transformer Service Inc.

Installation and Acceptance Testing

TSI’s experienced crews and licensed high voltage electricians are capable of installing, dressing, and acceptance testing of transformers and switchgear, large or small. TSI has a crane truck for equipment up to 9000 lbs and rents a crane for larger installations. We also have tankers and transformer oil treatment equipment for any size job.