Transformer Field Services

Transformer Field Services

Transformer Field Services

Transformer Field Services


Transformer Field Services. We have experienced Field Service teams that work nationally. PSIs (Pre Site Inspections) done for each Transformer before drawing oil samples. We have the ability to purify oil on site with our mobile oil plants and also have the ability to work underground.

Our dedicated team manage each account with precision and commitment. We make use of an independent laboratory. This means ISO 17025 accreditation, including 9001 and 14001. All analysis of oil samples performed to INTERNATIONAL STANDARDS AND PROCEDURES.

Transformer product range

Distribution and power transformers

These Transformers are in popular use. They range from small pole mounted transformers to large transformers. Like those seen out in distribution yards and substations. Typically robust oil-natural, air natural (ONAN) cooling methods used. This is due to the remoteness of the installation site. And added complexity of other cooling options..

Tax tip!
Transformers are an investment item. They are only written off for tax purposes over some years. Whereas a predictive maintenance cost is an expense item and is written off in the year incurred.

Mini Subs

Our Miniature Substations are of modular design for custom contract requirements. Our designs offer options for SF6 and oil filled high voltages. Swich gear with custom build low voltage and auxiliary feeder circuits.

Standard ratings range from 100kVA to 1600kVA with voltages up to 33kV.

Miniature substations with primary voltage rating of 33kV supplied without high voltage switch gear.

NEC / NER / AUX Transformers

Voltages up to 33kV

Special Transformers

Converter transformers

These Transformers are ideal to supply variable speed drives (VSD) for motor control. A VSD typically injects a whole spectrum of harmonics into the supply lines. The transformer’s design needs to accommodate these harmonics. A converter transformer is usually rated at 100% capacity when a Distribution transformer is at 80%.

Furnace Transformers

The smelting industry uses AC & DC processes depending on the Arc Furnace application.

DC Electric Arc Furnace (EAF) Transformers are similar in design to rectifier transformers. But have many more taps and on-load tap-changers.

AC (EAF) transformers are subjected to repeat short circuit conditions. This requires a more conservative design. They too have many taps and on-load tap changers. The AC (EAF) Transformers are generally manufactured as single phase units. Allowing for optimal the furnace processes.

Rectifier Transformers

These transformers cover a large range of configurations. The IEC60076 standards lists 19 configurations. The two most commonly used rectifiers are:

  • The three phase bridge rectifier (uses a normal 3 phase design)
  • And the 6 phase double star with inter-phase transformer (IPT). The IPT requires a dual secondary winding transformer design

We offer extended delta, phase shifted transformers. Suitable where impedance and voltage matching is critical in a twelve pulse plant.

A dual voltage Mobile Substation (specially manufactured for Eskom). Used in open cast mines where the primary of the transformer can be temporarily connected to an overhead line

Special Application transformers

Transformers supplying dedicated or non-distribution type loads designed to customer specific requirements.
Some of the more frequent applications are:

  • Transformers supplying 6 pulse and 12 pulse rectifier circuits
  • Earthing transformers with auxiliary voltage supply
  • Isolation transformers
  • Auto – wound transformers with either primary or secondary voltage variation
  • Neutral Earthing resistors and many more


  1. Transformer Oil Sampling/Analysis
  2. Purification/Filtration of transformer oil
    For optimized life span | On site purification
  3. Supply of transformer oil
    Virgin and Regenerated oil needed for annual maintenance
  4. Supply of transformer components
    Silica gel | Breathers | HT & LT bushings | Bucholz | Oil temperature gauges | Winding temperature gauges | Sight glass / Oil level indicator
  5. Repair or replacement
    Leaking gaskets | Cone rubbers | Transformer bushings | Drain valves | Bucholz |Transformer covers & cable boxes
  6. Spray painting of transformers and construction of transformer substations
    according to specification

Complete refurbishment of transformers in compliance with SABS standards and client’s specifications.

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