Table 65. Inverse time characteristics for undervoltage protection
Function
Range or value
Accuracy
Type A curve:
=
< -
<
æ
ö
ç
÷
è
ø
k
t
U
U
U
EQUATION1431-SMALL V1 EN
U< = U
set
U = UV
measured
k = (0.05-1.10) in steps of
0.01 unless otherwise stated
Class 5 +40 ms
Type B curve:
2.0
480
0.055
32
0.5
×
=
+
< -
×
-
<
æ
ö
ç
÷
è
ø
k
t
U
U
U
EQUATION1432-SMALL V1 EN
U< = U
set
U = U
measured
k = (0.05-1.10) in steps of
0.01 unless otherwise stated
Transformer protection RET650
1MRK 504 127-BEN -
Product version: 1.1
Issued: February 2011
72
ABB