Oil-filled transformers

BEZ oil-filled transformers are a proven and reliable product ensuring a long lifecycle and continuous energy supply in the power grid. Our state-of-the-art oil-filled transformers are being produced hermetically sealed or equipped with an oil conservator. It has become a standard, however, to use the advanced features of the hermetically sealed transformers. The oil is fully separated from the surrounding air making periodic oil analysis obsolete.

The selected cooling medium is based on the technological and environmental requirements and includes the options for mineral oil, silicone oil, or the ecological dielectric medium for installations in areas sensitive to environmental limitations such as water reservoirs.

We comply with the Ecodesign EU directive 548/2014.

Basic technical specifications

Power (hermeticaly sealed)25 kVA - 5 MVA
Power (breathing type)2500 kVA - 16 MVA
Rated voltageup to 35 kV
Frequency50 Hz, 60 Hz
Voltage regulationoff-circuit, or on-load tap changer (OLTC)
Optionalindoor / out door / pole mounted / very low losses

For more detailed information go to the downloads section or contact us at bez.or@bez.sk

Cast-resin transformers

BEZ cast-resin transformers are environmentally friendly, thus are the preferred option in locations where safety is a must.  These locations include nature protected environments, urban areas, high-rise buildings, hospitals, wind turbines, or nuclear power plants. Cast resin transformers are safe, secure, maintenance free with almost unlimited possibilities of installation.

Basic technical specifications

Power (up to 22 kV)25 kVA - 6300 kVA
Power (up to 35 kV)100 kVA - 4000 kVA
Power (outdoor use, up to 22 kV)5 kVA - 630 kVA
Frequency50 Hz, 60 Hz
CoolingAN, AF
  • Temperature sensors in the LV windings - 2 PTC thermistors or PT 100/phase
  • Temperature monitoring device with alarm and tripping contacts and cooling fans control
  • Dial thermometer
  • Antivibrations pads
  • Placement of LV/HV terminals

Safety and reliability

BEZ cast-resin transformers are designed and tested to ensure safe operation even in tough environments. Our transformers meet the strictest norms and are guaranteed to meet the following:

  • Fire resistance class: F1
  • Climatic resistance class: C2
  • Ambient resitstance class: E2
  • Temperature resistance: -60 °C

For more detailed information go to the dowloads section or contact us at bez.or@bez.sk

Special transformers

BEZ special purpose transformers are equipped for less common applications such as in heavy duty industrial processes like smelting operations, or in utilities such as railways. In situations which require extreme efficiency and low losses are a must. All BEZ transformers are highly customizable to meet the specific usage requirements.

Single-phase transformers

A single-phase transformer is frequently used for power distribution and voltage reduction for residential and lighter commercial applications. Single phase transformers are most commonly used in non-urban areas, where it is not economical to have a trhee-phase transformer.


Rectifier transformers

Rectifier transformers are used for industrial processes which require a significant direct current (dc) supply.


Excitation transformers

Excitation transformers are used in the excitation systems to magnetize generators and synchronous motors. The excitation transformer is an essential part of a generator. Our experience ensures the reliability of your system.


Grounding transformers

A grounding (also known as earthing) transformers is a three-phase transformer connected to the power system to provide a missing neutral connection for earthing. Grounding transformer provides a relatively low-impedance path to ground, thereby maintaining the system neutral at or near ground potential.


Amorphous transformers

An amorphous metal transformer (AMT) is a type of extremely efficient transformer featuring extremely low losses found on electric grids. The magnetic core of this transformer is made with a ferromagnetic amorphous metal. More efficient transformers lead to a reduction of generation requirement and, when using electric power generated from fossil fuels, less CO2 emissions.


For more detailed information contact us at bez.or@bez.sk


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