Ungrounded voltage transformers NOL.11-6.O5 (НОЛ.11-6.O5)

Ungrounded voltage transformers NOL.11-6.O5 (НОЛ.11-6.O5)

Ungrounded voltage transformer NOL.11-6.O5Description

The transformers are intended for embedding into factory-assembled switchgears with the circuit breaker VS-6400 and are used for powering control circuit and gears of the high voltage explosion-proof circuit breakers of the factory-assembled switchgears, as well as for controlling voltage in mining high voltage circuit of alternating current of 50 Hz or 60 Hz frequency.
The transformers are manufactured in compliance with the standard requirements of GOST 15150 in climatic version "O" (generally used) location category 5. The transformers are intended for usage under the following operating conditions:

  • altitude above sea level is not higher than 1000 m;
  • air temperature within operation period considering inside overheating of complete apparatus is from minus 10 °C to plus 45 °C;
  • ambient air humidity is 100 % at 35 °C and at the lower temperatures with moisture condensation;
  • environment should be non-explosive, without reactive steams in concentrations that are likely to destroy metal or insulation;
  • no direct influence of solar radiation;
  • mounting in any position.

The transformer is patented
Patent Certificates №6266 and 6267 

Table 1. Technical data


Normal value

Voltage class, kV


Maximum operating voltage, kV


Rated voltage of primary winding , V


Rated voltage of secondary winding , V:






Rated burden for the tapping x-a1 in accuracy class: 3, VA

250 **


Rated burden for the tapping x-a2 in accuracy class: 3, VA



Maximum power, V·A


Voltage drop at the three times overcharge in comparison with the maximum burden for tapping x-a2, %, no more than 



Allowed deviation of transformation ratio from the normal for the tapping x-a2, %, no more than


Rated frequency, Hz

50 or 60

* It is allowed to use both tappings simultaneously

** It is possible to manufacture transformers with rated burden of 50 VA for the tapping x-a1 in accuracy class 0,5. Should be specified in the order. 

General view of transformer (drawing)