BE1-51/27R - General Information
1-5
Characteristic curves: - continued
Nine I
2
T with extended timing range
Five British Standard 142 (E curves)
Seven integrating inverse time
Nine integrating I
2
T
Seven integrating inverse time with extended timing range
Nine integrating I
2
T with extended timing range
Timing option Z1 (16 position switch selects B & C curves (curves B1 - B8 and C1 - C8)):
Seven inverse time
Nine I
2
T
Timing option Z1 with option 2-D or 2-E, (16 position switch selects B & C curves):
Seven inverse time with extended timing range
Nine I
2
T with extended timing range
Timing option Z2 (16 position switch selects B and E (BS142) curves):
Seven inverse time
One I
2
T
Five British Standard 142 (E curves)
Timing option Z2 with option 2-D or 2-E, (16 position switch selects B and E (BS142) curves):
Seven inverse time with extended timing range
One I
2
T with extended timing range
Five British Standard 142 (E curves)
Timing option Z3 (16 position switch selects B and C curves):
Seven integrating inverse time
Nine integrating I
2
T
Timing option Z3 with option 2-D or 2-E, (16 position switch selects integrating extended B & C
curves):
Seven integrating inverse time with extended timing range
Nine integrating I
2
T with extended timing range
Characteristic curves are shown by the graphs in Figures 1-2 through 1-70. Note that each graph (i.e.
function) consists of a set of representative curves. Each curve (as well as any between-curve interpolation)
is selected by the front panel TIME DIAL using a two-digit designation from 00 to 99. Because of space
limitations, each graph shows only 14 of the 100 possible selections.
Non-Integrating Timing
Timing options Z1 and Z2 and the characteristic curves available with those options use non-integrating
timing. Non-integrating timing is accomplished by timing at a gate that is not solely dependent on the
magnitude of the applied multiple of pickup current. The time-out value is calculated based on the type of
time curve characteristic selected, time dial setting, and the magnitude of the applied multiple of pickup
current. The time-out value is continuously updated during the timing cycle. When pickup is exceeded, a
timer is initiated. When the timer elapsed time exceeds the calculated time-out value, a time trip output
signal is generated.
This type of non-integrating time delay characteristic exhibits a dynamic characteristic that is immediately
responsive to changes of the applied multiple of pickup current.