Toshiba GR200 Series Instruction Manual page 151

where,
t = time required for the element to reset fully after complete operation (seconds),
I = energizing current (amperes),
I s = threshold setting (amperes),
RTMS = time multiplier setting for resetting,
kr = time required to reset fully after complete operation when the energizing current is
zero (seconds),
β = constants defining curve.
For the IEEE standard, the user should use the setting [OC1-RTMS-IEEE] (incidentally,
the default value is 1.000). For the US standard and the original, settings [OC1-RTMS-US] and
[OC1-RTMS-ORG] are provided, respectively (For more information w.r.t the value for kr and
β, see Table 2.6-3; Figure 2.6-3 shows the characteristic curves).
†Note: To select the inverse-time-reset characteristic, set [OC1-Rtimer]=DEP.
Conversely set [OC1-Rtimer]=DEF to select definite-time-reset characteristic,.
Note: For the setting [OC1-Rtimer]=DEP (inverse-time-reset), the integrated value will
be reduced in accordance to the magnitude of an energized current, when the
energized current is smaller than the setting [OC1]. The reducing degree will be
determined with the reset curve characteristics defined in the standards.
Note: For the setting [OC1-Rtimer]=DEF (definite-time-reset), the integrated value shall
be zero when an energized current is smaller than the setting [OC1], when the
small energized current is continued for timer setting [TOC1R]. The integrated
value will not be zero when the energized current does not flow small for the
setting [TOC1R]. DEF is allowed to set in the IEEE, US, and ORG. DEF is set
unconditionally in the IEC and UK (see Table 2.6-5).
Table 2.6-3 Constants for inverse-time-reset characteristics
Curve Type
IEC 60255-151
A IEC Normal Inverse (IEC-NI)
B IEC Very Inverse (IEC-VI)
C IEC Extremely Inverse (IEC-EI)
- UK Long Time Inverse (UK-LTI)
D IEEE Moderately Inverse (IEEE-MI)
E IEEE Very Inverse (IEEE-VI)
F IEEE Extremely Inverse (IEEE-EI)
- US CO8 inverse (US-CO8)
- US CO2 short time inverse (US-CO2)
Curve Description
- 137 -
6F2S1931 (0.20)
kr
Β
sec
N/A N/A
N/A N/A
N/A N/A
N/A N/A
4.85 2
21.6 2
29.1 2
5.95 2
2.261 2
Centralized GRB200
(Soft: 030, 031, 032, 033, 034)