Epoxy cast resin Power Transformers

RITZ produces transformers in Glass Fibre reinforced Vacuum Technology (GVT) for ratings up to 25 MVA and 40,5 kV voltage class for various applications as follows.

  • Power Distribution
  • Rectifier Drives
  • Generator Excitation
  • Transmitter Systems
  • Earthing Systems
  • Traction Supply Systems
  • Oil Platforms/Vessels
  • Injection Systems
  • Laboratory Systems

All transformers can be supplied inside enclosures up to protection class IP54.

RITZ offers a customized service by providing:

  • Transformer installation
  • Disposal of existing oil and PCB transformers
  • Start-up

Glass Fibre reinforced Vacuum Technology (GVT) is used for High Voltage coils and optionally for Low Voltage coils in order to guarantee the highest possible quality and reliability to avoid cracks or voids during manufacturing and service.

The main design features are:

  • Protection against electricity surges
  • Free of partial discharge
  • Protection against short circuiting
  • High mechanical strength
  • Cooling channels in HV and LV coils
  • Pre-galvanised steel frame

RITZ transformers are designed according to the required international standards such as DIN/VDE or IEC. Furthermore, they fulfil all climatic, environmental and fire protection requirements

  • Environmental class E2
  • Climate class C2
  • Fire protection class F1
  • Basic surge level, list 2

The environmental protection requirements are taken into account in the design of RITZ Cast Resin Transformers.

High Voltage Coil

The copper winding of the High Voltage (HV) coil is insulated using glass fibre epoxy resin laminate. The HV coil is cast into moulds in a vacuum process with pure epoxy resin. The manufacturing process ensures a cavity free insulating system of the highest quality. The HV coil is free of partial discharge and protected against surges.
Tapping links are brought onto the outside of each coil and are readily adjustable when switched off. The HV coils are flame-resistant and self extinguishing. The HV coil can be designed with air ducts to cool the windings efficiently at a technically suitable coil length. Tapping links are brought out onto the outside face of each coil and are readily adjustable in deenergized state. The HV coils are hardly inflammable and self extinguishing. In case of fire no toxic fumes are produced.

Low Voltage Coil

The Low Voltage Coil (LV) consists of copper conductors formed in a vacuum process with epoxy resin impregnation to temperature class F. As an option, LV coils can be supplied as HV (GVT) design. This is usually undertaken for voltage ratings above 1kV.


The core lamination is made of low loss, cold rolled grain oriented silicon steel. The cross section of the iron has a circular shape. The core is cut stacked using a “Step Lap” formation to keep the idle periods and magnetizing currents as low as possible. The core is completely coated with epoxy resin to protect it against corrosion and is earthed in accordance with the required standards.


The coils are mounted on pre-adjusted fibreglass reinforced supports wit excellent thermal expansion and noise-absorbing properties. The complete assembly is mounted on bi-directional rollers which allow movement in both directions. HV terminals and LV bus bars are normally on the opposite sides of the transformer and are mounted at easily accessible positions.


Thermistors (PTC) are embedded in each LV coil and connected to terminals mounted on the upper clamp. As an alternative, PT 100 can be provided for the LV coils. An electronic relay with alarm and trip contacts (voltage free) is provided.


RITZ is certified according to DIN EN ISO 9001:2000 and undertakes testing to all applicable international standards. The complete transformer is subject to all routine testing including partial discharge test (pre-test and complete). Type testing and special tests can be performed on request.

Dry Type Transformers

Production facilities allow manufacturing of custom made dry type transformers and reactors. Flexible winding and core design is available to meet a wide range of transformers for special applications and requirements. Different manufacturing technologies such as Glass fibre reinforced Vacuum Technology (GVT), vacuum impregnation or encapsulation with mineral filled epoxy resin can be used. Application of heat shrinking tapes and protective resin provides the highest mechanical strength and good moisture protection.

Dry type transformers are available for the following applications:

  • Injection transformers for ripple control applications
  • Reactors for ripple control applications
  • High current transformers
  • Earthing transformers
  • Mittelfrequenztransformatoren
  • Medium frequency transformers
  • Filter and blocking reactors
  • Smoothing reactors

Pole Mounted Transformers

RITZ offers a wide range of pole mounted transformers with outdoor weatherproof enclosures especially designed for pole mounting. RITZ pole mounted cast resin transformers are the preferred substitute for the liquid filled transformers particularly in environmentally sensitive areas. The transformers are designed and tested as a complete assembly unit ensuring safe use and protection against electric shock. The transformers have undergone testing in both wet and dry conditions.