This article concerns the Schneider NSX 100 circuit breaker used in Sirius.

In Sirius we have only connected the SD contact which indicates ANY kind of trip – even one coming from the undervoltage coil. This is why we always have the fault MCB.

MCB origin

Cause

State card DIM

Fault Label

SKMCB pin15 to SD contact (Trip indication – page 47 of user manual)

  • Magnetic trip
  • Thermal trip
  • Phase unbalance/loss
  • Trip by Undervoltage coil (MN)
  • MCB locked out with padlock

Digital bank0 -> Bit 0

MCB FAULT

SDE contact exists but we have not connected it unfortunately. This should give us the info about whether it was a thermal trip.

  • Magnetic trip
  • Thermal trip

Not used

Not connected. The fault is generated by the state card.

Mbc contact state does not match command status:

  • Broken MCB motor
  • Command not arriving at MCB
  • Undervoltage coil current interrupted

Digital bank1 -> Bit 2

MCB WRONG STATUS

MCB Fault

Only in 18kV systems

Digital bank 1 -> Bit 5

From Page 47 of the Schneider NSX 100 user manual