Services & Maintenance
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Transformer Maintenance

Our qualified technicians have all the necessary skills and hands on experience to carry out


 repairs and maintenance on all makes and types of transformers and tap changers


 according to manufacturers’ standards.

All sizes of transformers from 25kVA up to 80MVA

  • Bushing replacement
  • Maintenance of tap changers
  • Transformer oil sampling and analysis – Performed by accredited laboratories
  • Transformer oil purification and regeneration
  •  “On line” purification of oil
  • Repairs of oil leaks and re-gasket of transformers include mini-substations









DZL-A series of double stage high efficient vacuum oil purifier is mainly used in the

purification of insulation oil in electrical transformer under 500KV. It can remove free and

dissolved water, dirt, air and gases from dielectric oil to maintain its purity and improve its

installation property so as to ensure the safe operation of the electrical transformer.


It is widely used for purification, degassing and dehydration process for insulating oils in

electrical transformers under 500KV. It is widely used in electrical transformers, inducation

equipment, capacitors, high- voltage switches etc. It can be used on site and online while

the transformer is in use and avoid service interruption. It can also be used for injection of

oil into the transformer under vacuum conditions or drying out the transformer with hot oil





When the insulation oil comes into the vacuum vessel for treatment, the pressure within the

vessel  is usually 1% of the normal atmosphere pressure. The ebullient point of free and

dissolved water in oil decreases in such a vacuum condition. So water in the oil decreases

in such a vacuum condition.  So water in the oil starts boiling and vapouring ever at low

temperature of 40-60, while a high temperature (above 100) will be hazardouse to affect the

oil quality. Wimann Electrical assuring customers of our best service at all times and

looking forward  in rendering you our service in the purification of transformer oils

Looking forward in quoting you for this services



Switchgear – Maintenance & Supply


Skilled technicians and Specialists are trained to carry out installation, commissioning and

testing of circuit breakers and transformers.  Our experience includes turnkey projects as

well as ad-hoc supply, install and commissioning. On-site maintenance on all makes and

types of metal clad switchgear from 2.2 kV up to and including 132kV. Supply of a limited

range of breaker contacts for various makes of switchgear.

(Moving & fixed)

On-site maintenance would include the following testing:
  • Timing tests (Speed tests)
  • Ductor tests (Resistance tests)
  • Insulation test (Megger test)
  • Minimum voltage test (Trip and close coils)
  • High Pot testing (vacuum bottles)
  • Issuing test certificates



Isolator Maintenance


  • Isolator maintenance all makes and types.
  • Stripping down of isolators for maintenance & repairs.
  • Installation and commissioning of new isolators.


On-site maintenance would include the following testing:

  • Ductor tests (Resistance tests)
  • Insulation test (Megger test)
  • Issuing test certificates



Maintenance, repairs and refurbishment of mini-substations, ring main units

and testing on GEC and Hawker and Siddeley mini-substation types for Eskom.



Fixed & permanent earthing & related work

  • Brazed connections
  • Soil resistivity testing
  • Exothermic welding
  • Line performance of transmission towers and similar structures
  • Installing damaged and stolen earth mats in substations with Exoweld SABS
  • Rrods for Eskom, Spoornet and Tshwane Municipality.



We are equipped to carry out line construction and maintenance on all types of overhead lines up to 132kV:


  • 3.3 kV DC line repairs and construction
  • Repairs and construction on AC supply lines.
  • Construction of new 11 kV lines.
  • Replacing of stolen conductor on all types of overhead lines and DC rail for supply to track.
  • Stringing of HV and LV ABC type conductor.
  • LV house connections