Could someone explain X/R in relation to interruption
Could someone explain X/R in relation to interruption
(OP)
We typically have to interupt breakers with a X/R between 6.6 and 8 with X and R in series but our lab gives us around 11.25. Which one is more severe on the breaker interruption a higher X/R or a lower one?






RE: Could someone explain X/R in relation to interruption
A higher X/R usually indicates a higher level of fault current at the interrupting time, which is typically 3-8 cycles after the momentary fault value.
RE: Could someone explain X/R in relation to interruption
RE: Could someone explain X/R in relation to interruption
Regards
Marmite
RE: Could someone explain X/R in relation to interruption
Whilst what I said is true in respect of the voltage, DPC has the right explanation in terms of the effect of X/R on breaking fault current.The breaker has to interrupt the symmetrical current (Normal AC fault current)with the asymmetrical current caused by the release of stored energy in the inductance superimposed on top. The mechanical analogy would be a spring (Inductance) attached to a damper (resistor). If you increase the proportion of resistance in respect of inductance (reactance) you apply more damping and the stored energy dissipates more quickly.
Regards
Marmite
RE: Could someone explain X/R in relation to interruption
thanks much
RE: Could someone explain X/R in relation to interruption
the angle is arctan(X/R)
arctan(6.6) = 81 deg
RE: Could someone explain X/R in relation to interruption
θ=arctan(X/R)
RE: Could someone explain X/R in relation to interruption