Utility Relay Company AC-PRO-II, Instruction Manual

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AC-PRO-II
®
Instruction Manual www.utilityrelay.com
Page 43
Pick-Up
20%
40% 60%
100%
200%
20%
40% 60% 100%
200%
OFF & 10A steps
20% to 200% of CT Rating
200% QT GF
S
E
C
O
NDS
.01
.1
1
10
100
1000
Quick-Trip Ground Fault Time Current Curve
(QT GF Pick-Up)
Current in Percent of CT Rating
20% QT GF
Pick-Up
Quick-Trip Ground Fault Pick-Up
QT I Pick-Up
(QT I) Pick-Up
LT Pick-Up
100A steps
Current in Multiples of Long Time Pick-Up
20X 2X
.01
150%
1X
QT I Pick-Up
6X 4X
1200%
10X
.1
.5
1
5
Quick-Trip Instantaneous Time Current Curve
Quick-Trip Instantaneous
150% to 1200% of
S
E
C
O
NDS
(1A steps for CTs < 225A)
(10A steps for CTs < 225A)
4X 1X 2X 10X 6X 20X
R
R
R R
AC-PRO-II Q.T. Rev 1.02 01/15/2015
CT Secondary Rating 0.5A and above
1200A max
50% to 200% of CT Rating
CT Secondary Rating below 0.5A
CT ratios above 24000
1200A only
(requires VDM or 24VDC)
QT-GF ends at
12 x CT Rating
Figure 18.4: QUICK-TRIP Ground Fault and QUICK-TRIP Instantaneous TCCs