Cast resin Transformer
LS CAST RESIN Transformers take pride in the ability to offer a wide variety of designs and configurations necessary to satisfy customer needs. Computer and CAD/CAM systems are used for quick and accurate design and manufacture to meet specific customer requirements.


The LS CAST RESIN Transformer has succeeded in combining the advantage of oil-filled and conventional dry type transformers, which are fabricated with an epoxy resin. The windings are completely embeded under vacuum conditions. This casting method makes it possible to assure void-free epoxy penetration of both the inner layer and turn to turn insulation.


Winding types and methods that offer the least loss were selected using magnetic field analysis, and also used in the LS Industrial System’s Power Transformer to ensure high levels of efficiency. Moreover, by selecting the optimal insulating structure through the electric field analysis of insulation between turns, sections, windings and phases, the Power Transformer’s electrical stability is achieved. LSfluent analysis technology has enabled the realization of an optimal cooling system, and 3D structure strength analysis has enabled a structural design that can withstand internal mechanical power short-circuits caused by system faults, seismic conditions according to external impacts, and the impact of transportation.

LS Industrial Systems’ Power Transformer factory is equipped with the latest core processor machines,
the latest winding machines, high-capacity vacuum heat drying equipment, state-of-the-art cleaning facilities, and has the best test room.

Environmentally safe

LS CAST RESIN Transformers will not emit oil or toxic gases into the atmosphere. Therefore, they do not pollute the environment and are strongly recommended as areplacement for askarel(PCB)-filled transformers.

Moisture proof

The complete casting of coils under vacuum prevents the penetration of moisture into the winding. Therefore, it is suitable for both storage and operation in harsh environment and is capable of being switched on immediately after such storage without pre-drying.

No partial discharge

There is no possibility of partial discharge in LS CAST RESIN Transformers. Whole core & coil is tested to guarantee the life expectancy of the insulation system. LS CAST RESIN Transformers are free of partial discharge at least up to 1.3 times of the rated voltage.

Low noise

The coating of the core with an epoxy resin have lead to an appreciable noise reduction. Noise is also reduced due to the sound suppresing effect of the step lap cutting.

Environmentally safe

Based on the high thermal time constant factor of the windings, LS CAST RESIN Transformers can be overloaded for a short duration considerably higher than oil-immersed transformers. It has a greater capability to withstand sudden high overloads such as might be encountered in heavy traction applications.

High impulse strength

LS CAST RESIN Transformers are very resistant to impulse voltage. Impulse withstand levels to 200kV are available because of careful design and special structure.

Maintenance free

Maintenance is almost completely eleminated. No checking of liquid level and no dielectric test for moisture absorption is required. Due to the smooth coil surface, heavy dirt and dust build up is eleminated even under the worst circumstances. The recommended routine maintenance is an occasional visual inspection.

Fire resistant

LS CAST RESIN Transformers have a very excellent characteristic of self fire-extinguishing and fire resistance. So there would be no fear of spread of fire even if fire took place around the electricity room.


Rated voltage

  • HV COIL : up to 36kV
  • LV COIL : up to 600V
    * Dual High voltage coils can also be supplied.

Standard Tapping range : ±2.5%, ±5%

  • Other ratings are available by request

Power capacity

  • Single phase : 20 ~ 2,000kVA
  • Three phase : 50 ~ 20,000kVA

Frequency : 50Hz, 60Hz

  • Other frequency is available by request

% Impedance voltage

  • ANSI STD. : 5.75%
  • IEC STD. : 4 ~ 6.00%
    * Other % impedance voltages are available.


  • HV COIL : Delta
  • LV COIL : Star with neutral point
    * Other connections are available to meet requirement.

Temperature class(According to IEC 726)

  • HV COIL and LV COIL : F CLASS* H class coils are available by request.


  • Copper (standard)
  • Aluminum (optional)

Noise Level(according to NEMA Std.)

  • 500kVA – 60dB
  • 750kVA – 64dB
  • 1000kVA – 64dB
  • 1500kVA – 65dB
  • 2000kVA – 66dB
  • 2500kVA – 68dB
    *Noise reduction TRs are available by request.