Toshiba GR200 Series - Page 290

6F2S1914 (0.49)
GRL200 (Soft 033 & 037)
- 267 -
defines the reset time for the inverse-time-reset characteristic (ref. IEC 60255-151):

󰇛

󰇜
 

  󰇡




󰇢


(2.17-2)
where:
t = time required for the element to reset fully after complete operation (seconds),
I = energizing current (amperes),
Is = threshold setting (amperes),
kr = time required to reset fully after complete operation when the energizing current is
zero
RTMS = time multiplier setting for resetting.
β = constants defining curve.
For setting RTMS for the IEEE standard, the user can use setting [OCN1-RTMS-IEEE]
(incidentally, the default value is 1.000). Similarly, settings [OCN1-RTMS-US] and [OCN1-
RTMS-ORG] are provided for the US standard and the original, respectively (For more
information w.r.t the values for kr and β, see Table 2.17-3; Figure 2.17-4 shows the
characteristic curves).
Table 2.17-3 Constants for inverse-time-reset characteristics
Curve Type
IEC 60255-151
Curve Description
kr
(sec)
β
A
IEC Normal Inverse (IEC-NI‡)
N/A
N/A
B
IEC Very Inverse (IEC-VI‡)
N/A
N/A
C
IEC Extremely Inverse (IEC-EI‡)
N/A
N/A
-
UK Long Time Inverse (UK-LTI‡)
N/A
N/A
D
IEEE Moderately Inverse (IEEE-MI)
4.85
2
E
IEEE Very Inverse (IEEE-VI)
21.6
2
F
IEEE Extremely Inverse (IEEE-EI)
29.1
2
-
US CO8 inverse (US-CO8)
5.95
2
-
US CO2 short time inverse (US-CO2)
2.261
2
†Note: To select the inverse-time-reset characteristic, set [OCN1-Rtimer]=DEP.
Conversely set [OCN1-Rtimer]=DEF to select definite-time-reset characteristic,.
Note: For the setting [OCN1-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 [OCN1]. The reducing degree will be
determined with the reset curve characteristics defined in the standards.
Note: For the setting [OCN1-Rtimer]=DEF (definite-time-reset), the integrated value
shall be zero when an energized current is smaller than the setting [OCN1], when
the small energized current is continued for timer setting [TOCN1R]. The
integrated value will not be zero when the energized current does not flow small
for the setting [TOCN1R]. DEF is allowed to set in the IEEE, US, and ORG. DEF is
set unconditionally in the IEC and UK (see Table 2.17-4).