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Buchholz Relay BS25,BS50,BS80

Buchholz Relay BS25,BS50,BS80

Type testing

  • Measurement of the volume of gas necessary to trip the alarm
  • 500 hour salt fog
  • Electromagnetic Field test (EN 50216-2)
  • Stationary sinusoidal mechanical vibrations (EN60721-3-4)
  • A seismic test was performed (EN 50216-1)
  • Pressure withstand test 2.5 bar two minutes with oil at 100 deg C.
  • Vacuum withstand test of 2500 Pa for 24 Hrs
  • Rate of flow test to operate trip contacts
  • Test to show the relay is insensitive to oil flow from conservator to transformer
  • Electrical test

Routine tests applied to all Relays

  • Hydraulic seal test in mineral oil at
    • 90 °C. and
    • 100 kPa pressure for
    • 30 minutes
  • Contact operation
    • Mechanical push rod
  • Contact operation
    • Lowering the oil
  • Rate of oil flow to trip the contacts
  • Electrical withstand test between contacts
  • Electrical withstand test between contacts and earth

An individual routine test report is shipped with each relay

Buchholz Relay BS25,BS50,BS80


South African specification range
Code Description
BHR25MA BS 25mm
BHR50MA BS 50mm
BHR80MA BS 80mm
BHR25MABV BS 25mm with Valve
BHR50MABV BS 50mm with Valve
BHR80MABV  BS 80mm with Valve

Code Description
BHR25MEA BS 25mm
BHR50MEA BS 50mm
BHR25MEABV BS 25mm with Valve
BHR50MEABV BS 50mm with Valve

Gas Sampling Device
Code Description
On Request Gas sampling device