AC-PRO
®
& AC-PRO-II
®
B-292 Secondary Injection Test Set Instruction Manual Rev 1.1
www.utilityrelay.com
Page 21
5.3
Calculate Quick-Trip Ground Fault
(QT-GF) Pick-Up Secondary Current
Calculate the QT-GF secondary pick-up current
(QT-GF
SPU
) as follows:
For 1-Amp AC-PRO or AC-PRO-II:
QT-GF
SPU
= QT-GF Pick-Up
CT Primary Rating
Example: If the CT Primary rating is 1600 and
the QT-GF pick-up is 1200 amps, then:
QT-GF
SPU
= 1200 = 0.75 amp
1600
For 0.5-Amp AC-PRO or AC-PRO-II:
QT-GF
SPU
= QT-GF Pick-Up X 0.5
CT Primary Rating
Example: If the CT Primary rating is 1600 and
the QT-GF pick-up is 1200 amps, then:
GF
SPU
= 1200 X 0.5 = 0.38 amp
1600
Note: If CT Secondary Rating is different than 1.0 or 0.5,
use the 0.5 example above and replace 0.5 with the
specific CT Secondary Rating.
5.4
Quick-Trip Ground Fault (QT-GF)
Pick-Up Test
Verify that the Ground Fault Type (10) selector
switch is in the correct position for the
AC-PRO or AC-PRO-II being tested.
To test the QT-GF pick-up:
1)
AC-PRO: Connect the Quick-Trip
Display (P) and the Quick-Trip
ON/OFF Selector switch (Q) as
shown in Figure 7.
AC-PRO-II: Connect the AC-PRO-II
Quick-Trip switch (U) as shown in
Figure 8.
2)
Set the Quick-Trip ON/OFF Selector
switch (Q) or (U) to ON.
3)
Set the Phase Selector (11) switch to
GF.
4)
Hold down the Current Preset (13)
while adjusting the Amp Coarse (14)
and Fine (15) pots to 90% of the
calculated QT-GF
SPU.
5)
Push the Start (5) button but leave the
test current on only long enough to see
if a QT-GF trip occurs.
A QT-GF trip should NOT occur.
6)
Hold down the Current Preset (13)
while adjusting the Amp Coarse (14)
and Fine (15) pots to 110% of the
calculated QT-GF
SPU.
7)
Push the Clear (8) button to reset the
Timer (6) to zero.
8)
Push the Start (5) button.
A QT-GF trip should occur. The test set
current will stop and the Timer (6) will
freeze displaying the trip time.
9)
Set the Quick-Trip ON/OFF Selector
switch (Q) or (U) to OFF.
10)
Push the Start (5) button but leave the
test current on only long enough to see
if a QT-GF trip occurs.
A QT-GF trip should NOT occur.
11)
Verify that the trip unit saved the proper
last trip data.
