Two inverse time overcurrent elements on log log axes, from the GE Multilin 850's own published curve equation. Every trip time here is checked against the 210 published in its manual.
The manual states one of its own cells in prose on p.4-124: an Extremely Inverse curve at TDM = 2, with fault current 5× pickup, "will not occur before 2.59 s". Three independent representations inside that one document agree, and this page computes the third of them live:
| Representation | Manual p.4-115 / 4-124 | This page |
|---|---|---|
| Prose worked example | 2.59 s | |
| Table 4-35 cell | 2.593 s | |
| Equation + Table 4-34 | 2.5934 s |
All 210 cells of Table 4-35 are recomputed in verify/verify.js, which is the gate
this project shipped behind. 210 of 210 agree; the worst disagreement is 0.135%, which is the
table's own rounding to three decimals.
Curve family: GE Multilin 850, Table 4-34. This tool reproduces one named manufacturer's published curves and claims no standards conformance. GE and SEL both cite IEEE C37.112-1996 over different constants, about 5× apart, and C37.112 itself is gated and unread here.
There is no pass and no fail here, deliberately. The customary interval is a rule of thumb its
own source words as "usually", and an if statement would turn that into a
limit the source declined to state. The band is drawn so you can judge against it. The judgment
stays with you.