Toshiba GR200 Series Instruction Manual page 292

Pick-up characteristic
The IDMT characteristic is applied when the operation of the UVS1 element is required
inversely in accordance with the level of input voltage. The IDMT characteristic curve is
illustrated in Figure 2.16-2 using a value of time multiplier is set for [UV1-TMS]. It is followed
to Equation (2.16-1) in conformed in IEC 60255-127
where,
t = operating time (seconds),
V = energizing voltage (voltage),
Vs = pickup voltage setting (voltage),
TMS = time multiplier setting.
Except for pre-programmed characteristics, the user can have a user-programmable
(original) characteristic curve. The user-programmable (original) curve is obtained when the
constants of k, a, c, as shown in Table 2.16-2, are set, and when Original is set for scheme
switch [UVS1-Timer]. The constants are set with settings [UVS1-k], [UVS1-a], and [UVS1-C].
1000.000
100.000
10.000
1.000
Figure 2.16-2 IDMT characteristics curves depending on TMS
t ( G ) = TMS × {[
1 − ( �� ��
Undervoltage Inverse Time Curves
TMS=10
TMS=5
TMS=2
TMS=1
0 0.2 0.4
Applied Voltage (x Vs)
- 271 -
��
] + ��}
��
⁄ )
��
0.6 0.8 1
6F2S1915 (0.46)
(2.16-1)
GRZ200 (Soft 031 & 032)