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Medium voltage vacuum switches VB-17


VB-17 medium voltage breaker switches are intended for use in power systems. The electric arc is extinguished with the vacuum technique. Disconnection in vacuum occurs with the minimum arc breaking current. This ensures high electric durability of the disconnecting switch and limits mechanical, electric and thermal exposures of the installed elements.
Breaker switches are used to isolate electricity and protect cables, overhead lines, transformers and substations, motors, generators or capacitor batteries.


  • The switch may be operated manually or electrically
  • On request of the recipient, the breaker switch may be fitted with the following electric control elements:
  • – The motor with the gear for putting closing springs under tension automatically
    – The closing release
    – The opening release

  • manual tensioning of springs is always possible
  • breaker switches may be installed directly on the support structures owned by the recipient or special trucks (available on request)
  • withdrawable breaker switches are designed for use in metal-enclosed two-stage switchgears
  • when the breaker switch is in the “test” position, it may be inserted in the switchgear, because it is then earthed through the rollers of the drawer

Operational conditions

  • Installation altitude up to 1,000 m ASL
  • No need to compensate for vibration from external factors or earthquake
  • No significant pollution with salt, steam, dust, smoke, flammable or corrosive gases
  • No icing, frosting and dew
  • Relative air humidity:
  • – the highest average within the day: 95%
    – the highest average within the month: 90%
    – the highest average steam pressure within the day: 2.2 kPa
    – the highest average steam pressure within the month: 1.8 kPa

  • Ambient temperature:
  • – the highest short-term temperature: +40°C
    – the highest average within the day: +35°C
    – the highest annual average: +20°C
    – the lowest long-term temperature: +25°C

Standard equipment of circuit breakers

  • the manual drive mechanism
  • the mechanical indicator of spring tension (on/off)
  • the mechanical indicator of the disconnecting switch status (open/closed)
  • the closing button
  • the opening button
  • the operations counter
  • a set of 10 auxiliary contacts: 5 normally open and 5 normally closed. Some accessories of the disconnecting switch take auxiliary contacts and reduce their number to be used by the client
  • the manual drive activation lever
  • tulip contacts
  • the cable with the connector (only plugs) for auxiliary circuits with the stop that prevents inserting the plug in the socket if nominal current of the disconnecting switch differs from the rated current of the panel
  • the withdrawing lever (state the number for the ordered instruments)
  • the electromagnet blocking in the travelling unit; it prevents entering the disconnecting switch into the switchgear bay with auxiliary circuits; unconnected (the plug not connected to the socket)


  • Nominal voltage 12; 17,5 kV
  • Nominal current 630; 1250; 1600; 2000; 2500; 3150 A
  • Nominal disconnecting capacity 20; 31,5 kA
  • Rated short-time withstand current 20; 31,5 kA/3s
  • Rated peak withstand current 50; 80 kA
  • Highest voltage / Rated short-time withstand voltage of grid frequency / Rated lightning impulse withstand voltage:
    12 kV12/28/75
    17,5 kV17,5/38/95
  • Nominal voltage of auxiliary circuits: Direct current / Alternate current110, 220 / 110, 220 V
  • Closing time 0,07 s
  • Total opening time 0,045 s
  • Arc time 0,015 s
  • Operating sequenceO -0,3 s – CO – 180 s – CO
  • Pole pitch 150; 210; 275 mm
  • Dimensions W/D/H450; 570; 620; 750 / 412; 448 / 482; 637
  • Weight kg70÷260