Dry Type Transformers for Power and Distribution

Dry Type Transformers

TMC has a long and successful history of production of dry type power and distribution transformers (also known as “open winding dry type transformers”).

TMC produces dry type transformers with capacities up to 10MVA and voltages up to 36kV. Dry-type transformers use air as their main cooling medium and have neither the liquid leakage hazard nor the associated maintenance and potential flammability problems inherent in liquid filled units.

TMC dry type power transformers are designed, manufactured and tested in accordance with the latest issue of IEC and Australian standards according to customer specifications. Modern non-hygroscopic insulation materials permit the use of ventilated dry type transformers in most environments found in commercial, industrial and mining applications. The low voltage windings are wound from full-width foil to provide the highest short circuit strength and have excellent cooling performance. The medium voltage winding are wound from rectangular cross-section wire supported by combs. The combs are precision manufactured to provide uniform mechanical and electrical spacing. All windings are mouldless vacuum cast to provide protection against high humidity, mechanical and chemical effects


The transformers can be supplied in enclosures to various degrees of protection, or open (un-enclosed) if preferred. Enclosure ratings of IP21 to IP33 are common and protection up to IP66 is also available for extreme conditions and flameproof applications. Enclosures are fitted with sealed marshalling boxes for temperature and performance monitoring equipment. Enclosures can be fitted with interlocked doors and limit switches to provide additional safety

Fan Cooling

TMC dry type transformers can be supplied with fans to increase the rated capacity (kVA). Forced directed air circulation permits a continuous power increase of up to 35% above the rated capacity. Fans can be used to economically provide extra capacity for overload conditions such as cyclic load peaks and traction loads.

Information Required with Enquiry:

  • Rated power
  • Voltages (at no-load)
  • Voltage tapping range.
  • Impedance
  • Overload conditions
  • Natural or fan cooling
  • Number of phases
  • Operating frequency
  • Connection symbol (Vector group)
  • Ambient conditions
  • Design standard
  • Enclosure protection rating
  • Temperature sensing equipment
  • Current sensing equipment (CT’s).