Table 575: RI and RD type inverse time characteristics
Function Range or value Accuracy
RI type inverse characteristic
EQUATION1656 V1 EN
I = I
measured
/I
set
td = (0.05-999) in steps of 0.01
RD type logarithmic inverse characteristic
= - ×
æ ö
ç ÷
è ø
5.8 1.35t
I
In
td
EQUATION1657 V1 EN
I = I
measured
/I
set
td = (0.05-999) in steps of 0.01
Table 576: Inverse time characteristics for overvoltage protection
Function Range or value Accuracy
Type A curve:
=
-
æ ö
ç ÷
è ø
t
td
V VPickup
VPickup
EQUATION1661 V1 EN
V = V
measured
td = (0.05-1.10) in steps of
0.01
±5% +60 ms
Type B curve:
=
×
-
× - -
æ ö
ç ÷
è ø
2.0
480
32 0.5 0.035
t
td
V VPickup
VPickup
EQUATION1662 V1 EN
td = (0.05-1.10) in steps of
0.01
Type C curve:
=
×
-
× - -
æ ö
ç ÷
è ø
3.0
480
32 0.5 0.035
t
td
V VPickup
VPickup
EQUATION1663 V1 EN
td = (0.05-1.10) in steps of
0.01
1MRK 511 287-UUS A Section 19
Time inverse characteristics
663
Technical manual